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Document and Entity Information - USD ($)	3 Months Ended
Document and Entity Information - USD ($)	Mar. 31, 2011	Apr. 22, 2011	Jun. 30, 2010
Document and Entity Information [Abstract]
Entity Registrant Name	M&T BANK CORP
Entity Central Index Key	0000036270
Document Type	10-Q
Document Period End Date	Mar. 31, 2011
Amendment Flag	false
Document Fiscal Year Focus	2010
Document Fiscal Period Focus	Q1
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Public Float			$ 6,778,614,643
Entity Common Stock, Shares Outstanding		120,789,167

Consolidated Balance Sheet (Unaudited) - USD ($) $ in Thousands	Mar. 31, 2011	Dec. 31, 2010
Assets
Cash and due from banks	$ 972,005	$ 908,755
Interest-bearing deposits at banks	100,101	101,222
Federal funds sold	10,300	25,000
Trading account	413,737	523,834
Investment securities (includes pledged securities that can be sold or repledged of $1,901,174 at March 31, 2011; $1,937,817 at December 31, 2010)
Available for sale (cost: $4,932,460 at March 31, 2011; $5,494,377 at December 31, 2010)	4,854,984	5,413,492
Held to maturity (fair value: $1,173,836 at March 31, 2011; $1,225,253 at December 31, 2010)	1,262,089	1,324,339
Other (fair value: $390,092 at March 31, 2011; $412,709 at December 31, 2010)	390,092	412,709
Total investment securities	6,507,165	7,150,540
Loans and leases	52,435,574	52,315,942
Unearned discount	(316,893)	(325,560)
Loans and leases, net of unearned discount	52,118,681	51,990,382
Allowance for credit losses	(903,703)	(902,941)
Loans and leases, net	51,214,978	51,087,441
Premises and equipment	431,292	435,837
Goodwill	3,524,625	3,524,625
Core deposit and other intangible assets	113,603	125,917
Accrued interest and other assets	4,593,402	4,138,092
Total assets	67,881,208	68,021,263
Liabilities
Noninterest-bearing deposits	15,219,562	14,557,568
NOW accounts	1,424,848	1,393,349
Savings deposits	27,331,587	26,431,281
Time deposits	5,508,432	5,817,170
Deposits at Cayman Islands office	1,063,670	1,605,916
Total deposits	50,548,099	49,805,284
Federal funds purchased and agreements to repurchase securities	441,196	866,555
Other short-term borrowings	63,480	80,877
Accrued interest and other liabilities	1,015,495	1,070,701
Long-term borrowings	7,305,420	7,840,151
Total liabilities	59,373,690	59,663,568
Shareholders' equity
Preferred stock, $1.00 par, 1,000,000 shares authorized, 778,000 shares issued and outstanding (liquidation preference $1,000 per share)	743,385	740,657
Common stock, $.50 par, 250,000,000 shares authorized, 120,396,611 shares issued	60,198	60,198
Common stock issuable, 66,015 shares at March 31, 2011; 71,345 shares at December 31, 2010	3,889	4,189
Additional paid-in capital	2,367,556	2,398,615
Retained earnings	5,534,909	5,426,701
Accumulated other comprehensive income (loss), net	(197,521)	(205,220)
Treasury stock - common, at cost - 52,284 shares at March 31, 2011; 693,974 shares at December 31, 2010	(4,898)	(67,445)
Total shareholders' equity	8,507,518	8,357,695
Total liabilities and shareholders' equity	$ 67,881,208	$ 68,021,263

Consolidated Balance Sheet (Unaudited) (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2011	Dec. 31, 2010
Assets
Pledged securities that can be sold or repledged	$ 1,901,174	$ 1,937,817
Investment securities, available for sale, amortized cost	4,932,460	5,494,377
Investment securities, held to maturity, fair value	1,173,836	1,225,253
Other debt securities fair value	$ 390,092	$ 412,709
Shareholders' equity
Preferred stock, par value	$ 1.00	$ 1.00
Preferred stock, shares authorized	1,000,000	1,000,000
Preferred stock, shares issued	778,000	778,000
Preferred stock, shares outstanding	778,000	778,000
Preferred stock, liquidation preference per share	$ 1,000	$ 1,000
Common stock, par value	$ 0.50	$ 0.50
Common stock, shares authorized	250,000,000	250,000,000
Common stock, shares issued	120,396,611	120,396,611
Common stock issuable, shares	66,015	71,345
Treasury stock - common, shares	52,284	693,974

Consolidated Statement of Income (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2011	Mar. 31, 2010
Interest income
Loans and leases, including fees	$ 594,032	$ 588,127
Deposits at banks	36	6
Federal funds sold	18	11
Agreements to resell securities	1	2
Trading account	388	83
Investment securities
Fully taxable	70,662	85,647
Exempt from federal taxes	2,346	2,510
Total interest income	667,483	676,386
Interest expense
NOW accounts	202	200
Savings deposits	19,239	20,449
Time deposits	19,071	29,446
Deposits at Cayman Islands office	394	325
Short-term borrowings	492	887
Long-term borrowings	59,281	68,745
Total interest expense	98,679	120,052
Net interest income	568,804	556,334
Provision for credit losses	75,000	105,000
Net interest income after provision for credit losses	493,804	451,334
Other income
Mortgage banking revenues	45,156	41,476
Service charges on deposit accounts	109,731	120,295
Trust income	29,321	30,928
Brokerage services income	14,296	13,106
Trading account and foreign exchange gains	8,279	4,699
Gain on bank investment securities	39,353	459
Total other-than-temporary impairment ("OTTI") losses	(9,514)	(29,487)
Portion of OTTI losses recognized in other comprehensive income (before taxes)	(6,527)	2,685
Net OTTI losses recognized in earnings	(16,041)	(26,802)
Equity in earnings of Bayview Lending Group LLC	(6,678)	(5,714)
Other revenues from operations	91,003	79,259
Total other income	314,420	257,706
Other expense
Salaries and employee benefits	266,090	264,046
Equipment and net occupancy	56,663	55,401
Printing, postage and supplies	9,202	9,043
Amortization of core deposit and other intangible assets	12,314	16,475
FDIC assessments	19,094	21,348
Other costs of operations	136,208	123,049
Total other expense	499,571	489,362
Income before taxes	308,653	219,678
Income taxes	102,380	68,723
Net income	206,273	150,955
Net income available to common shareholders
Basic	190,113	136,428
Diluted	$ 190,121	$ 136,431
Net income per common share
Basic	$ 1.59	$ 1.16
Diluted	1.59	1.15
Cash dividends per common share	$ 0.70	$ 0.70
Average common shares outstanding
Basic	119,201	117,765
Diluted	119,852	118,256

Consolidated Statement of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2011	Mar. 31, 2010
Cash flows from operating activities
Net income	$ 206,273	$ 150,955
Adjustments to reconcile net income to net cash provided by operating activities
Provision for credit losses	75,000	105,000
Depreciation and amortization of premises and equipment	17,978	17,207
Amortization of capitalized servicing rights	13,478	14,645
Amortization of core deposit and other intangible assets	12,314	16,475
Provision for deferred income taxes	11,438	(10,163)
Asset write-downs	17,720	27,821
Net (gain) loss on sales of assets	(44,504)	1,461
Net change in accrued interest receivable, payable	5,068	98
Net change in other accrued income and expense	2,063	80,537
Net change in loans originated for sale	373,020	252,227
Net change in trading account assets and liabilities	80,805	(2,664)
Net cash provided by operating activities	770,653	653,599
Cash flows from investing activities
Proceeds from sales of available for sale investment securities	13,380	14,759
Proceeds from sales of other investment securities	22,969	11,478
Proceeds from maturities of available for sale investment securities	408,574	369,136
Proceeds from maturities of held to maturity investment securities	66,465	29,828
Purchases of available for sale investment securities	(353,508)	(34,084)
Purchases of held to maturity investment securities	(7,796)	(969,953)
Purchases of other investment securities	(352)	(428)
Net (increase) decrease in loans and leases	(579,845)	546,709
Net decrease in interest - bearing deposits at banks	1,121	12,030
Other investments, net	(8,769)	(6,198)
Additions to capitalized servicing rights	(1,195)	(57)
Capital expenditures, net	(8,854)	(10,570)
Other, net	35,231	(10,305)
Net cash used by investing activities	(412,579)	(47,655)
Cash flows from financing activities
Net increase in deposits	745,021	93,998
Net decrease in short-term borrowings	(442,751)	(571,827)
Payments on long-term borrowings	(528,511)	(252,880)
Dividends paid - common	(84,718)	(83,303)
Dividends paid - preferred	(10,056)	(10,056)
Other, net	11,491	15,451
Net cash used by financing activities	(309,524)	(808,617)
Net increase (decrease) in cash and cash equivalents	48,550	(202,673)
Cash and cash equivalents at beginning of period	933,755	1,246,342
Cash and cash equivalents at end of period	982,305	1,043,669
Supplemental disclosure of cash flow information
Interest received during the period	665,490	684,212
Interest paid during the period	88,658	121,445
Income taxes paid during the period	77,169	14,250
Supplemental schedule of noncash investing and financing activities
Real estate acquired in settlement of loans	$ 18,168	20,749
Increase (decrease) from consolidation of securitization trusts:
Loans		423,865
Investment securities-available for sale		(360,471)
Long-term borrowings		65,419
Accrued interest and other		$ 2,025

Consolidated Statement of Changes in Shareholders' Equity (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2011	Mar. 31, 2010
Statement [Line Items]
Beginning Balance	$ 8,357,695	$ 7,752,907
Comprehensive income:
Net income	206,273	150,955
Other comprehensive income, net of tax and reclassification adjustments:
Unrealized gains on investment securities	5,658	79,856
Defined benefit plans liability adjustment	2,111	1,030
Unrealized gains on terminated cash flow hedge	(70)	(70)
Other comprehensive income	213,972	231,771
Preferred stock cash dividends	(10,498)	(10,056)
Repayment of management stock ownership program receivable		155
Stock-based compensation plans:
Compensation expense, net	10,868	16,129
Exercises of stock options, net	19,548	7,698
Directors' stock plan	272	263
Deferred compensation plans, net, including dividend equivalents	(60)	(50)
Other	513	471
Common stock cash dividends - $0.70 per share	(84,792)	(83,601)
Ending Balance	8,507,518	7,915,687
Preferred stock
Statement [Line Items]
Beginning Balance	740,657	730,235
Other comprehensive income, net of tax and reclassification adjustments:
Amortization of preferred stock discount	2,728	2,534
Stock-based compensation plans:
Ending Balance	743,385	732,769
Common stock
Statement [Line Items]
Beginning Balance	60,198	60,198
Stock-based compensation plans:
Ending Balance	60,198	60,198
Common stock issuable
Statement [Line Items]
Beginning Balance	4,189	4,342
Stock-based compensation plans:
Deferred compensation plans, net, including dividend equivalents	(300)	(269)
Ending Balance	3,889	4,073
Additional paid-in capital
Statement [Line Items]
Beginning Balance	2,398,615	2,442,947
Other comprehensive income, net of tax and reclassification adjustments:
Repayment of management stock ownership program receivable		155
Stock-based compensation plans:
Compensation expense, net	(20,796)	(23,297)
Exercises of stock options, net	(10,524)	(8,471)
Directors' stock plan	(32)	(145)
Deferred compensation plans, net, including dividend equivalents	(220)	(258)
Other	513	471
Ending Balance	2,367,556	2,411,402
Retained earnings
Statement [Line Items]
Beginning Balance	5,426,701	5,076,884
Comprehensive income:
Net income	206,273	150,955
Other comprehensive income, net of tax and reclassification adjustments:
Preferred stock cash dividends	(10,498)	(10,056)
Amortization of preferred stock discount	(2,728)	(2,534)
Stock-based compensation plans:
Deferred compensation plans, net, including dividend equivalents	(47)	(48)
Common stock cash dividends - $0.70 per share	(84,792)	(83,601)
Ending Balance	5,534,909	5,131,600
Accumulated other comprehensive income (loss), net
Statement [Line Items]
Beginning Balance	(205,220)	(335,997)
Other comprehensive income, net of tax and reclassification adjustments:
Unrealized gains on investment securities	5,658	79,856
Defined benefit plans liability adjustment	2,111	1,030
Unrealized gains on terminated cash flow hedge	(70)	(70)
Stock-based compensation plans:
Ending Balance	(197,521)	(255,181)
Treasury stock
Statement [Line Items]
Beginning Balance	(67,445)	(225,702)
Stock-based compensation plans:
Compensation expense, net	31,664	39,426
Exercises of stock options, net	30,072	16,169
Directors' stock plan	304	408
Deferred compensation plans, net, including dividend equivalents	507	525
Other	0	0
Ending Balance	$ (4,898)	$ (169,174)

Consolidated Statement of Changes in Shareholders' Equity (Unaudited) (Parenthetical) - $ / shares	3 Months Ended
	Mar. 31, 2011	Mar. 31, 2010
Retained earnings
Statement [Line Items]
Common stock per share dividend amount	$ 0.70	$ 0.70

Significant accounting policies	3 Months Ended
Significant accounting policies	Mar. 31, 2011
Significant accounting policies [Abstract]
Significant accounting policies	1. Significant accounting policies The consolidated financial statements of M&T Bank Corporation (“M&T”) and subsidiaries (“the Company”) were compiled in accordance with generally accepted accounting principles (“GAAP”) using the accounting policies set forth in note 1 of Notes to Financial Statements included in the 2010 Annual Report. In the opinion of management, all adjustments necessary for a fair presentation have been made and were all of a normal recurring nature.

Acquisitions

3 Months Ended

Mar. 31, 2011

Acquisitions [Abstract]

Acquisitions

2. Acquisitions

On November 5, 2010, M&T Bank, M&T’s principal banking subsidiary, entered into a purchase and assumption agreement with the Federal Deposit Insurance Corporation (“FDIC”) to assume all of the deposits, except certain brokered deposits, and acquire certain assets of K Bank, based in Randallstown, Maryland. As part of the transaction, M&T Bank entered into a loss-share arrangement with the FDIC whereby M&T Bank will be reimbursed by the FDIC for most losses it incurs on the acquired loan portfolio. The transaction was accounted for using the acquisition method of accounting and, accordingly, assets acquired and liabilities assumed were recorded at estimated fair value on the acquisition date. Assets acquired in the transaction totaled approximately $556 million, including $154 million of loans and $186 million in cash, and liabilities assumed aggregated $528 million, including $491 million of deposits. In accordance with GAAP, M&T Bank recorded an after-tax gain on the transaction of $17 million ($28 million before taxes). The gain reflects the amount of financial support and indemnification against loan losses that M&T Bank obtained from the FDIC. There was no goodwill or other intangible assets recorded in connection with this transaction. The operations obtained in the K Bank acquisition transaction did not have a material impact on the Company’s consolidated financial position or results of operations.

On November 1, 2010, M&T announced that it had entered into a definitive agreement with Wilmington Trust Corporation (“Wilmington Trust”), headquartered in Wilmington, Delaware, under which Wilmington Trust will be acquired by M&T. Pursuant to the terms of the agreement, Wilmington Trust common shareholders will receive .051372 shares of M&T common stock in exchange for each share of Wilmington Trust common stock in a stock-for-stock transaction valued at $351 million (with the price based on M&T’s closing price of $74.75 per share as of October 29, 2010), plus the assumption of $330 million in preferred stock issued by Wilmington Trust as part of the Troubled Asset Relief Program — Capital Purchase Program of the U.S. Department of Treasury (“U.S. Treasury”).

At December 31, 2010, Wilmington Trust had approximately $10.9 billion of assets, including $7.5 billion of loans, $10.1 billion of liabilities, including $9.0 billion of deposits, and $60.1 billion of combined assets under management, including $43.6 billion managed by Wilmington Trust and $16.5 billion managed by affiliates. At a special shareholder meeting held on March 22, 2011, Wilmington Trust’s common shareholders approved the merger transaction. M&T announced on April 26, 2011 that it had received the approval of the Board of Governors of the Federal Reserve System to acquire Wilmington Trust. Additional regulatory approvals, including those from the New York State Banking Superintendent and the Delaware Banking Commissioner, are still pending. Subject to the terms and conditions of the merger agreement, M&T expects to close the merger with Wilmington Trust promptly after receiving the remaining regulatory approvals and after the 15-day waiting period associated with the Federal Reserve Board’s approval order has expired.

In connection with the K Bank acquisition transaction and the pending Wilmington Trust acquisition, the Company incurred merger-related expenses related to systems conversions and other costs of integrating and conforming acquired operations with and into the Company. Those expenses consisted largely of professional services and other temporary help fees associated with the conversion of systems and/or integration of operations; costs related to branch and office consolidations; initial marketing and promotion expenses designed to introduce M&T Bank to its new customers; travel costs; and printing, postage, supplies and other costs of completing the transactions and commencing operations in new markets and offices. There were no merger-related expenses during the three months ended March 31, 2010. A summary of merger-related expenses associated with the acquisition transactions included in the consolidated statement of income for the three months ended March 31, 2011 follows:


	(in thousands)
Salaries and employee benefits	$	7
Equipment and net occupancy		79
Printing, postage and supplies		147
Other costs of operations		4,062

	$	4,295

Investment securities

3 Months Ended

Mar. 31, 2011

Investment securities [Abstract]

Investment securities

3. Investment securities

The amortized cost and estimated fair value of investment securities were as follows:


					Gross
	Amortized		Gross		unrealized		Estimated
	cost		unrealized gains		losses		fair value
	(in thousands)
March 31, 2011
Investment securities available for sale:
U.S. Treasury and federal agencies	$	38,531		758		150	$	39,139
Obligations of states and political subdivisions		59,010		442		62		59,390
Mortgage-backed securities:
Government issued or guaranteed		2,732,299		108,911		1,349		2,839,861
Privately issued residential		1,600,110		14,006		222,238		1,391,878
Privately issued commercial		23,232		—		2,765		20,467
Collateralized debt obligations		94,290		27,734		7,759		114,265
Other debt securities		306,870		29,980		30,301		306,549
Equity securities		78,118		7,121		1,804		83,435

		4,932,460		188,952		266,428		4,854,984


Investment securities held to maturity:
Obligations of states and political subdivisions		191,251		1,916		1,166		192,001
Mortgage-backed securities:
Government issued or guaranteed		758,611		11,743		—		770,354
Privately issued		299,780		—		100,746		199,034
Other debt securities		12,447		—		—		12,447

		1,262,089		13,659		101,912		1,173,836

Other securities		390,092		—		—		390,092

Total	$	6,584,641		202,611		368,340	$	6,418,912


			Gross		Gross
	Amortized		unrealized		unrealized		Estimated
	cost		gains		losses		fair value
	(in thousands)
December 31, 2010
Investment securities available for sale:
U.S. Treasury and federal agencies	$	61,772		1,680		18	$	63,434
Obligations of states and political subdivisions		59,921		561		57		60,425
Mortgage-backed securities:
Government issued or guaranteed		3,146,054		161,298		1,111		3,306,241
Privately issued residential		1,677,064		10,578		252,081		1,435,561
Privately issued commercial		25,357		—		2,950		22,407
Collateralized debt obligations		95,080		24,754		9,078		110,756
Other debt securities		310,017		26,883		38,000		298,900
Equity securities		119,112		5,098		8,442		115,768

		5,494,377		230,852		311,737		5,413,492


Investment securities held to maturity:
Obligations of states and political subdivisions		191,119		1,944		694		192,369
Mortgage-backed securities:
Government issued or guaranteed		808,108		14,061		—		822,169
Privately issued		312,537		—		114,397		198,140
Other debt securities		12,575		—		—		12,575

		1,324,339		16,005		115,091		1,225,253

Other securities		412,709		—		—		412,709

Total	$	7,231,425		246,857		426,828	$	7,051,454

Gross realized gains on investment securities were $39.4 million and $1.2 million for the quarters ended March 31, 2011 and 2010, respectively. Gross realized losses on investment securities were $36 thousand and $777 thousand for the quarters ended March 31, 2011 and 2010, respectively. During the three-month period ended March 31, 2011, the Company sold residential mortgage-backed securities guaranteed by the Federal National Mortgage Association (“Fannie Mae”) and the Federal Home Loan Mortgage Corporation (“Freddie Mac”) having an aggregate amortized cost of approximately $484 million which resulted in a gain of $39 million (pre-tax). The Company recognized $16 million (pre-tax) and $27 million (pre-tax) of other-than-temporary impairment losses during the quarters ended March 31, 2011 and 2010, respectively, related to privately issued mortgage-backed securities. The impairment charges were recognized in light of deterioration of real estate values and continued high levels of delinquencies and charge-offs of underlying mortgage loans collateralizing those securities. The other-than-temporary losses represent management’s estimate of credit losses inherent in the securities considering projected cash flows using assumptions for delinquency rates, loss severities, and other estimates of future collateral performance. The following table displays changes in credit losses for debt securities recognized in earnings for the three months ended March 31, 2011 and March 31, 2010.


	Three months ended
	March 31
	2011			2010
	(in thousands)
Beginning balance	$	327,912			284,513
Additions for credit losses not previously recognized		16,041			26,802
Reductions for increases in cash flows		(139	)		(169	)
Reductions for realized losses		(21,095	)		(3,129	)

Ending balance	$	322,719			308,017

At March 31, 2011, the amortized cost and estimated fair value of debt securities by contractual maturity were as follows:


	Amortized		Estimated
	cost		fair value
	(in thousands)
Debt securities available for sale:
Due in one year or less	$	7,437		7,532
Due after one year through five years		64,615		65,828
Due after five years through ten years		19,518		21,162
Due after ten years		407,131		424,821

		498,701		519,343
Mortgage-backed securities available for sale		4,355,641		4,252,206

	$	4,854,342		4,771,549


Debt securities held to maturity:
Due in one year or less	$	28,334		28,496
Due after one year through five years		14,306		14,719
Due after five years through ten years		140,556		140,782
Due after ten years		20,502		20,451

		203,698		204,448
Mortgage-backed securities held to maturity		1,058,391		969,388

	$	1,262,089		1,173,836

A summary of investment securities that as of March 31, 2011 and December 31, 2010 had been in a continuous unrealized loss position for less than twelve months and those that had been in a continuous unrealized loss position for twelve months or longer follows:


	Less than 12 months					12 months or more
	Fair		Unrealized			Fair		Unrealized
	value		losses			value		losses
			(in thousands)
March 31, 2011
Investment securities available for sale:
U.S. Treasury and federal agencies	$	23,884		(150	)		—		—
Obligations of states and political subdivisions		3,488		(26	)		2,062		(36	)
Mortgage-backed securities:
Government issued or guaranteed		69,731		(1,311	)		3,212		(38	)
Privately issued residential		7,675		(523	)		1,014,944		(221,715	)
Privately issued commercial		—		—			20,467		(2,765	)
Collateralized debt obligations		15,011		(5,567	)		8,156		(2,192	)
Other debt securities		3,767		(68	)		96,364		(30,233	)
Equity securities		2,652		(510	)		1,254		(1,294	)

		126,208		(8,155	)		1,146,459		(258,273	)


Investment securities held to maturity:
Obligations of states and political subdivisions		86,929		(1,128	)		470		(38	)
Privately issued mortgage-backed securities		—		—			193,752		(100,746	)

		86,929		(1,128	)		194,222		(100,784	)

Total	$	213,137		(9,283	)		1,340,681		(359,057	)


December 31, 2010
Investment securities available for sale:
U.S. Treasury and federal agencies	$	27,289		(18	)		—		—
Obligations of states and political subdivisions		3,712		(18	)		2,062		(39	)

Mortgage-backed securities:
Government issued or guaranteed		68,507		(1,079	)		2,965		(32	)
Privately issued residential		61,192		(1,054	)		1,057,315		(251,027	)
Privately issued commercial		—		—			22,407		(2,950	)
Collateralized debt obligations		12,462		(6,959	)		6,004		(2,119	)
Other debt securities		2,134		(10	)		88,969		(37,990	)
Equity securities		5,326		(3,721	)		673		(4,721	)

		180,622		(12,859	)		1,180,395		(298,878	)


Investment securities held to maturity:
Obligations of states and political subdivisions		76,318		(638	)		467		(56	)
Privately issued mortgage-backed securities		—		—			198,140		(114,397	)

		76,318		(638	)		198,607		(114,453	)

Total	$	256,940		(13,497	)		1,379,002		(413,331	)

The Company owned 562 individual investment securities with aggregate gross unrealized losses of $368 million at March 31, 2011. Approximately $323 million of the unrealized losses pertain to privately issued mortgage-backed securities with a cost basis of $1.5 billion. The Company also had $38 million of unrealized losses on trust preferred securities issued by financial institutions, securities backed by trust preferred securities issued by financial institutions and other entities, and other debt securities having a cost basis of $161 million. Based on a review of each of the remaining securities in the investment securities portfolio at March 31, 2011, with the exception of the aforementioned securities for which other-than-temporary impairment losses were recognized, the Company concluded that it expected to recover the amortized cost basis of its investment. As of March 31, 2011, the Company does not intend to sell nor is it anticipated that it would be required to sell any of its impaired investment securities. At March 31, 2011, the Company has not identified events or changes in circumstances which may have a significant adverse effect on the fair value of the $390 million of cost method investment securities.

Loans and Leases and the Allowance for Credit Losses

3 Months Ended

Mar. 31, 2011

Loans and Leases and the Allowance for Credit Losses [Abstract]

Loans and leases and the allowance for credit losses

4. Loans and leases and the allowance for credit losses

Interest income on acquired loans that were recorded at fair value at the acquisition date for the three months ended March 31, 2011 and 2010 was $41 million and $43 million, respectively. The outstanding principal balance and the carrying amount of such loans that is included in the consolidated balance sheet at March 31, 2011 is as follows:


	(in thousands)
Outstanding principal balance		$3,509,711
Carrying amount		3,184,469

Receivables obtained in acquisitions for which there was specific evidence of credit deterioration at the acquisition date and for which it was deemed probable that the Company would be unable to collect all contractually required principal and interest payments were not material.

A summary of current, past due and nonaccrual loans as of March 31, 2011 and December 31, 2010 were as follows:


			30-89
			Days		90 Days		Purchased
	Current		past due		past due		impaired		Nonaccrual		Total
					(in thousands)
March 31, 2011
Commercial, financial, leasing, etc.	$	13,605,508		24,626		21,055		1,922		173,188		13,826,299
Real estate:
Commercial		16,606,831		75,829		22,765		7,115		229,630		16,942,170
Residential builder and developer		886,832		21,859		4,493		68,442		320,295		1,301,921
Other commercial construction		2,421,823		97,824		17,327		2,013		108,537		2,647,524
Residential		4,983,032		194,594		195,241		6,897		178,109		5,557,873
Residential Alt-A		450,829		35,469		—		—		110,789		597,087
Consumer:
Home equity lines and loans		6,340,612		34,338		—		2,200		44,350		6,421,500
Automobile		2,545,546		33,784		—		—		29,839		2,609,169
Other		2,167,697		27,468		3,599		—		16,374		2,215,138

Total	$	50,008,710		545,791		264,480		88,589		1,211,111		52,118,681


			30-89
			Days		90 Days		Purchased
	Current		past due		past due		impaired		Nonaccrual		Total
	(in thousands)
December 31, 2010
Commercial, financial, leasing, etc.	$	13,088,887		96,087		16,647		2,250		186,739		13,390,610
Real estate:
Commercial		16,589,240		89,906		35,338		8,275		209,031		16,931,790
Residential builder and developer		891,764		30,805		9,763		72,710		346,448		1,351,490
Other commercial construction		2,723,399		36,420		11,323		2,098		126,641		2,899,881
Residential		4,699,711		229,641		192,276		9,320		172,729		5,303,677
Residential Alt-A		475,236		42,674		—		—		106,469		624,379
Consumer:
Home equity lines and loans		6,472,563		38,367		—		2,366		43,055		6,556,351
Automobile		2,608,230		44,604		—		—		31,892		2,684,726
Other		2,190,353		36,689		4,246		—		16,190		2,247,478

Total	$	49,739,383		645,193		269,593		97,019		1,239,194		51,990,382

Changes in the allowance for credit losses for the three months ended March 31, 2011 were as follows:


	Commercial,
	Financial,					Real Estate
	Leasing, etc.			Commercial			Residential			Consumer			Unallocated		Total
	(in thousands)
Beginning balance	$	212,579			400,562			86,351			133,067			70,382		902,941
Provision for credit losses		14,942			14,775			15,841			27,764			1,678		75,000
Net charge-offs
Charge-offs		(14,027	)		(24,579	)		(16,167	)		(28,321	)		—		(83,094	)
Recoveries		2,165			349			1,501			4,841			—		8,856

Net charge-offs		(11,862	)		(24,230	)		(14,666	)		(23,480	)		—		(74,238	)

Ending balance	$	215,659			391,107			87,526			137,351			72,060		903,703

Despite the above allocation, the allowance for credit losses is general in nature and is available to absorb losses from any portfolio segment. Changes in the allowance for credit losses for the three months ended March 31, 2010 were as follows:


	(in thousands)
Beginning balance	$	878,022
Provision for credit losses		105,000
Consolidation of loan securitization trusts		2,752
Net charge-offs
Charge-offs		(106,039	)
Recoveries		11,530

Net charge-offs		(94,509	)

Ending balance	$	891,265

In ascertaining the adequacy of the allowance for credit losses, the Company estimates losses attributable to specific troubled credits identified through both normal and detailed or intensified credit review processes and also estimates losses inherent in other loans and leases on a collective basis. For purposes of determining the level of the allowance for credit losses, the Company evaluates its loan and lease portfolio by loan type. The amounts of loss components in the Company’s loan and lease portfolios are determined through a loan by loan analysis of larger balance commercial and commercial real estate loans that are in nonaccrual status and by applying loss factors to groups of loan balances based on loan type and management’s classification of such loans under the Company’s loan grading system. Measurement of the specific loss components is typically based on expected future cash flows, collateral values and other factors that may impact the borrower’s ability to pay. In determining the allowance for credit losses, the Company utilizes an extensive loan grading system which is applied to all commercial and commercial real estate credits. Loan officers are responsible for continually assigning grades to these loans based on standards outlined in the Company’s Credit Policy. Internal loan grades are also extensively monitored by the Company’s loan review department to ensure consistency and strict adherence to the prescribed standards. Loan grades are assigned loss component factors that reflect the Company’s loss estimate for each group of loans and leases. Factors considered in assigning loan grades and loss component factors include borrower-specific information related to expected future cash flows and operating results, collateral values, financial condition, payment status, and other information; levels of and trends in portfolio charge-offs and recoveries; levels of and trends in portfolio delinquencies and impaired loans; changes in the risk profile of specific portfolios; trends in volume and terms of loans; effects of changes in credit concentrations; and observed trends and practices in the banking industry. Modified loans, including smaller balance homogenous loans, that are considered to be troubled debt restructurings are evaluated for impairment giving consideration to the impact of the modified loan terms on the present value of the loan’s expected cash flows. The following tables provide information with respect to impaired loans and leases as of March 31, 2011 and December 31, 2010 and for the three months ended March 31, 2011 and March 31, 2010.


	March 31, 2011						December 31, 2010
			Unpaid						Unpaid
	Recorded		principal		Related		Recorded		principal		Related
	investment		balance		allowance		investment		balance		allowance
	(in thousands)
With an allowance recorded:
Commercial, financial, leasing, etc.	$	102,977		153,773		33,363		121,744		170,888		40,909
Real estate:
Commercial		131,923		162,211		26,629		110,975		140,015		17,393
Residential builder and developer		250,433		304,636		65,578		263,545		295,031		78,597
Other commercial construction		84,617		110,488		12,839		80,934		85,432		22,067
Residential		83,405		101,223		3,945		73,006		85,279		3,375
Residential Alt-A		173,091		184,022		35,000		180,665		191,445		36,000
Consumer:
Home equity lines and loans		11,895		13,544		2,423		11,799		13,378		2,227
Automobile		59,465		59,465		12,774		58,858		58,858		12,597
Other		3,170		3,170		786		2,978		2,978		768

		900,976		1,092,532		193,337		904,504		1,043,304		213,933


With no related allowance recorded:
Commercial, financial, leasing, etc.		70,829		92,904		—		65,827		86,332		—
Real estate:
Commercial		101,076		120,472		—		101,939		116,316		—
Residential builder and developer		108,764		150,480		—		100,799		124,383		—
Other commercial construction		25,893		31,865		—		46,656		50,496		—
Residential		4,276		6,443		—		5,035		7,723		—
Residential Alt-A		29,285		50,272		—		28,967		47,879		—

		340,123		452,436		—		349,223		433,129		—


Total:
Commercial, financial, leasing, etc.		173,806		246,677		33,363		187,571		257,220		40,909
Real estate:
Commercial		232,999		282,683		26,629		212,914		256,331		17,393
Residential builder and developer		359,197		455,116		65,578		364,344		419,414		78,597
Other commercial construction		110,510		142,353		12,839		127,590		135,928		22,067
Residential		87,681		107,666		3,945		78,041		93,002		3,375
Residential Alt-A		202,376		234,294		35,000		209,632		239,324		36,000
Consumer:
Home equity lines and loans		11,895		13,544		2,423		11,799		13,378		2,227
Automobile		59,465		59,465		12,774		58,858		58,858		12,597
Other		3,170		3,170		786		2,978		2,978		768

Total	$	1,241,099		1,544,968		193,337		1,253,727		1,476,433		213,933


	Three months ended						Three months ended
	March 31, 2011						March 31, 2010
			Interest income						Interest income
			recognized						recognized
	Average						Average
	recorded				Cash		recorded				Cash
	investment		Total		basis		investment		Total		basis
	(in thousands)
Commercial, financial, leasing, etc.	$	184,546		1,007		1,001		331,564		455		455
Real estate:
Commercial		221,601		384		342		289,470		371		371
Residential builder and developer		362,129		527		130		321,822		44		44
Other commercial construction		126,054		510		321		55,297		384		384
Residential		83,527		1,034		596		45,822		532		349
Residential Alt-A		205,632		1,995		551		226,878		2,183		438
Consumer:
Home equity lines and loans		12,076		161		26		12,491		192		38
Automobile		58,863		984		296		50,253		861		348
Other		3,031		57		6		3,236		66		16

Total	$	1,257,459		6,659		3,269		1,336,833		5,088		2,443

The following table summarizes the loan grades applied to the various classes of the Company’s commercial and commercial real estate loans as of March 31, 2011 and December 31, 2010.


			Real Estate
	Commercial,				Residential		Other
	Financial,				Builder and		Commercial
	Leasing, etc.		Commercial		Developer		Construction
			(in thousands)
March 31, 2011
Pass	$	12,909,951		15,752,006		676,164		2,090,831
Criticized accrual		743,160		960,534		305,462		448,156
Criticized nonaccrual		173,188		229,630		320,295		108,537

Total	$	13,826,299		16,942,170		1,301,921		2,647,524


December 31, 2010
Pass	$	12,371,138		15,831,104		693,110		2,253,589
Criticized accrual		832,733		891,655		311,932		519,651
Criticized nonaccrual		186,739		209,031		346,448		126,641

Total	$	13,390,610		16,931,790		1,351,490		2,899,881

In assessing the adequacy of the allowance for credit losses, residential real estate loans and consumer loans are generally evaluated collectively after considering such factors as payment performance, collateral values and trends related thereto. However, residential real estate loans and outstanding balances of home equity loans and lines of credit that are more than 150 days past due are generally evaluated for collectibility on a loan-by-loan basis giving consideration to estimated collateral values.

The Company also measures additional losses for purchased impaired loans when it is probable that the Company will be unable to collect all cash flows expected at acquisition plus additional cash flows expected to be collected arising from changes in estimates after acquisition. In addition, the Company also provides an inherent unallocated portion of the allowance that is intended to recognize probable losses that are not otherwise identifiable and includes management’s subjective determination of amounts necessary to provide for the possible use of imprecise estimates in determining the allocated portion of the allowance.

At March 31, 2011 and December 31, 2010, the allocation of the allowance for credit losses summarized on the basis of the Company’s impairment methodology was as follows:


	Commercial,
	Financial,		Real Estate
	Leasing, etc.		Commercial		Residential		Consumer		Total
	(in thousands)
March 31, 2011
Individually evaluated for impairment	$	33,211		101,993		38,000		15,686	$	188,890
Collectively evaluated for impairment		182,296		286,061		48,581		121,368		638,306
Purchased impaired		152		3,053		945		297		4,447

Allocated	$	215,659		391,107		87,526		137,351		831,643

Unallocated										72,060


Total									$	903,703


December 31, 2010
Individually evaluated for impairment	$	40,459		114,082		39,000		15,492	$	209,033
Collectively evaluated for impairment		171,670		282,505		46,976		117,475		618,626
Purchased impaired		450		3,975		375		100		4,900

Allocated	$	212,579		400,562		86,351		133,067		832,559

Unallocated										70,382


Total									$	902,941

The recorded investment in loans and leases summarized on the basis of the Company’s impairment methodology as of March 31, 2011 and December 31, 2010 was as follows:


	Commercial,
	Financial,		Real Estate
	Leasing, etc.		Commercial		Residential		Consumer		Total
	(in thousands)
March 31, 2011
Individually evaluated for impairment	$	173,188		658,462		285,106		72,330	$	1,189,086
Collectively evaluated for impairment		13,651,189		20,155,583		5,862,957		11,171,277		50,841,006
Purchased impaired		1,922		77,570		6,897		2,200		88,589


Total	$	13,826,299		20,891,615		6,154,960		11,245,807	$	52,118,681


December 31, 2010
Individually evaluated for impairment	$	186,739		682,120		286,612		72,082	$	1,227,553
Collectively evaluated for impairment		13,201,621		20,417,958		5,632,124		11,414,107		50,665,810
Purchased impaired		2,250		83,083		9,320		2,366		97,019


Total	$	13,390,610		21,183,161		5,928,056		11,488,555	$	51,990,382

Borrowings	3 Months Ended
Borrowings	Mar. 31, 2011
Borrowings [Abstract]
Borrowings	5. Borrowings The Company had $1.2 billion of fixed and floating rate junior subordinated deferrable interest debentures (“Junior Subordinated Debentures”) outstanding at March 31, 2011 that are held by various trusts and were issued in connection with the issuance by those trusts of preferred capital securities (“Capital Securities”) and common securities (“Common Securities”). The proceeds from the issuances of the Capital Securities and the Common Securities were used by the trusts to purchase the Junior Subordinated Debentures. The Common Securities of each of those trusts are wholly owned by M&T and are the only class of each trust’s securities possessing general voting powers. The Capital Securities represent preferred undivided interests in the assets of the corresponding trust. Under the Federal Reserve Board’s current risk-based capital guidelines, the Capital Securities are includable in M&T’s Tier 1 capital. However, the Dodd-Frank Wall Street Reform and Consumer Protection Act of 2010 that was signed into law on July 21, 2010 provides for a three-year phase-in related to the exclusion of trust preferred capital securities from Tier 1 capital for large financial institutions, including M&T. That phase-in period begins on January 1, 2013. Holders of the Capital Securities receive preferential cumulative cash distributions unless M&T exercises its right to extend the payment of interest on the Junior Subordinated Debentures as allowed by the terms of each such debenture, in which case payment of distributions on the respective Capital Securities will be deferred for comparable periods. During an extended interest period, M&T may not pay dividends or distributions on, or repurchase, redeem or acquire any shares of its capital stock. In the event of an extended interest period exceeding twenty quarterly periods for $350 million of Junior Subordinated Debentures due January 31, 2068, M&T must fund the payment of accrued and unpaid interest through an alternative payment mechanism, which requires M&T to issue common stock, non-cumulative perpetual preferred stock or warrants to purchase common stock until M&T has raised an amount of eligible proceeds at least equal to the aggregate amount of accrued and unpaid deferred interest on the Junior Subordinated Debentures due January 31, 2068. In general, the agreements governing the Capital Securities, in the aggregate, provide a full, irrevocable and unconditional guarantee by M&T of the payment of distributions on, the redemption of, and any liquidation distribution with respect to the Capital Securities. The obligations under such guarantee and the Capital Securities are subordinate and junior in right of payment to all senior indebtedness of M&T. The Capital Securities will remain outstanding until the Junior Subordinated Debentures are repaid at maturity, are redeemed prior to maturity or are distributed in liquidation to the Trusts. The Capital Securities are mandatorily redeemable in whole, but not in part, upon repayment at the stated maturity dates (ranging from 2027 to 2068) of the Junior Subordinated Debentures or the earlier redemption of the Junior Subordinated Debentures in whole upon the occurrence of one or more events set forth in the indentures relating to the Capital Securities, and in whole or in part at any time after an optional redemption prior to contractual maturity contemporaneously with the optional redemption of the related Junior Subordinated Debentures in whole or in part, subject to possible regulatory approval. In connection with the issuance of 8.50% Enhanced Trust Preferred Securities associated with $350 million of Junior Subordinated Debentures maturing in 2068, M&T entered into a replacement capital covenant that provides that neither M&T nor any of its subsidiaries will repay, redeem or purchase any of the Junior Subordinated Debentures due January 31, 2068 or the 8.50% Enhanced Trust Preferred Securities prior to January 31, 2048, with certain limited exceptions, except to the extent that, during the 180 days prior to the date of that repayment, redemption or purchase, M&T and its subsidiaries have received proceeds from the sale of qualifying securities that (i) have equity-like characteristics that are the same as, or more equity-like than, the applicable characteristics of the 8.50% Enhanced Trust Preferred Securities or the Junior Subordinated Debentures due January 31, 2068, as applicable, at the time of repayment, redemption or purchase, and (ii) M&T has obtained the prior approval of the Federal Reserve Board, if required.

Shareholders' Equity

3 Months Ended

Mar. 31, 2011

Shareholders' equity [Abstract]

Shareholders' equity

6. Shareholders’ equity

M&T is authorized to issue 1,000,000 shares of preferred stock with a $1.00 par value per share. Preferred shares outstanding rank senior to common shares both as to dividends and liquidation preference, but have no general voting rights.

Issued and outstanding preferred stock of M&T is presented below:

Carrying

issued and

value

outstanding

March 31, 2011

December 31, 2010

(dollars in thousands)

Series A (a)

Fixed Rate Cumulative Perpetual

600,000

580,203

578,630

Preferred Stock, Series A, $1,000 liquidation preference per share, 600,000 shares authorized

Series B (b)

Series B Mandatory Convertible

26,500

Non-cumulative Preferred Stock, $1,000 liquidation preference per share, 26,500 shares authorized

Series C (a)(c)

Fixed Rate Cumulative Perpetual

151,500

136,682

135,527

Preferred Stock, Series C, $1,000 liquidation preference per share, 151,500 shares authorized


(a)		Shares were issued as part of the Troubled Asset Relief Program — Capital Purchase Program of the U.S. Department of Treasury (“U.S. Treasury”). Cash proceeds were allocated between the preferred stock and a ten-year warrant to purchase M&T common stock (Series A — 1,218,522 common shares at $73.86 per share, Series C — 407,542 common shares at $55.76 per share). Dividends, if declared, will accrue and be paid quarterly at a rate of 5% per year for the first five years following the original 2008 issuance dates and thereafter at a rate of 9% per year. The agreement with the U.S. Treasury contains limitations on certain actions of M&T, including the payment of quarterly cash dividends on M&T’s common stock in excess of $.70 per share, the repurchase of its common stock during the first three years of the agreement, and the amount and nature of compensation arrangements for certain of the Company’s officers.

(b)		Shares were assumed in an acquisition and a new Series B Preferred Stock was designated. Pursuant to their terms, the shares of Series B Preferred Stock were converted into 433,144 shares of M&T common stock on April 1, 2011. The preferred stock had a stated dividend rate of 10% per year.

(c)		Shares were assumed in an acquisition and a new Series C Preferred Stock was designated.

As noted by M&T at the time the merger with Wilmington Trust was announced on November 1, 2010, following completion of the merger, M&T expects its capital ratios at the end of the second quarter of 2011 to be comparable to what they were as of September 30, 2010. Pursuant to its capital plan, M&T intends to undertake a series of actions during the second quarter of 2011:

	•		Simultaneous with the closing of the merger, M&T intends to redeem the $330 million of preferred stock that was issued to the U.S. Treasury by Wilmington Trust pursuant to the Troubled Asset Relief Program — Capital Purchase Program;

	•		By the end of the second quarter of 2011, M&T intends to repay an additional $370 million of the preferred stock issued to the U.S. Treasury pursuant to the Troubled Asset Relief Program — Capital Purchase Program by Provident Bankshares Corporation and by M&T; and

	•		To supplement its Tier 1 capital, M&T will issue $500 million of new perpetual preferred stock prior to the end of the second quarter of 2011.

Pension plans and other postretirement benefits

3 Months Ended

Mar. 31, 2011

Pension plans and other postretirement benefits [Abstract]

Pension plans and other postretirement benefits

7. Pension plans and other postretirement benefits

The Company provides defined benefit pension and other postretirement benefits (including health care and life insurance benefits) to qualified retired employees. Net periodic benefit cost for defined benefit plans consisted of the following:


							Other
	Pension						postretirement
	benefits						benefits
	Three months ended March 31
	2011			2010			2011		2010
	(in thousands)
Service cost	$	5,300			4,875			125		100
Interest cost on projected benefit obligation		12,150			12,029			775		780
Expected return on plan assets		(12,700	)		(12,788	)		—		—
Amortization of prior service cost		(1,650	)		(1,650	)		25		25
Amortization of net actuarial loss		5,100			3,321			—		—


Net periodic benefit cost	$	8,200			5,787			925		905

Expense incurred in connection with the Company’s defined contribution pension and retirement savings plans totaled $10,176,000 and $11,690,000 for the three months ended March 31, 2011 and 2010, respectively.

Earnings per common share

3 Months Ended

Mar. 31, 2011

Earnings per common share [Abstract]

Earnings per common share

8. Earnings per common share

The computations of basic earnings per common share follow:


	Three months ended
	March 31
	2011			2010
	(in thousands,
	except per share)
Income available to common shareholders:

Net income	$	206,273			150,955
Less: Preferred stock dividends (a)		(10,498	)		(10,056	)
Amortization of preferred stock discount (a)		(2,753	)		(2,558	)

Net income available to common equity		193,022			138,341
Less: Income attributable to unvested stock-based compensation awards		(2,909	)		(1,913	)


Net income available to common shareholders	$	190,113			136,428

Weighted-average shares outstanding:

Common shares outstanding (including common stock issuable) and unvested stock-based compensation awards		120,992			119,324
Less: Unvested stock-based compensation awards		(1,791	)		(1,559	)


Weighted-average shares outstanding		119,201			117,765

Basic earnings per common share	$	1.59			1.16


(a)		Including impact of not as yet declared cumulative dividends.

The computations of diluted earnings per common share follow:


	Three months ended
	March 31
	2011			2010
	(in thousands,
	except per share)

Net income available to common equity	$	193,022			138,341
Less: Income attributable to unvested stock-based compensation awards		(2,901	)		(1,910	)


Net income available to common shareholders		190,121			136,431

Adjusted weighted-average shares outstanding:

Common and unvested stock-based compensation awards		120,992			119,324
Less: Unvested stock-based compensation awards		(1,791	)		(1,559	)
Plus: Incremental shares from assumed conversion of stock-based compensation awards and convertible preferred stock		651			491


Adjusted weighted-average shares outstanding		119,852			118,256

Diluted earnings per common share	$	1.59			1.15

GAAP defines unvested share-based awards that contain nonforfeitable rights to dividends or dividend equivalents (whether paid or unpaid) as participating securities that shall be included in the computation of earnings per common share pursuant to the two-class method. During the first quarters of 2011 and 2010, the Company issued stock-based compensation awards in the form of restricted stock and restricted stock units, which, in accordance with GAAP, are considered participating securities.

Stock-based compensation awards, warrants to purchase common stock of M&T and preferred stock convertible into shares of M&T common stock representing approximately 10.5 million and 11.9 million common shares during the three-month periods ended March 31, 2011 and 2010, respectively, were not included in the computations of diluted earnings per common share because the effect on those periods would have been antidilutive.

Comprehensive income

3 Months Ended

Mar. 31, 2011

Comprehensive income [Abstract]

Comprehensive income

9. Comprehensive income

The following table displays the components of other comprehensive income:


	Three months ended March 31, 2011
	Before-tax			Income
	amount			taxes			Net
	(in thousands)
Unrealized gains (losses) on investment securities:

Available-for-sale (“AFS”) investment securities with other-than-temporary impairment (“OTTI”):

Unrealized holding gains, net	$	7,930			(3,108	)		4,822
Less: OTTI charges recognized in net income		(7,541	)		2,949			(4,592	)

Net change for AFS investment securities with OTTI		15,471			(6,057	)		9,414


AFS investment securities — all other:

Unrealized holding gains, net		31,577			(12,372	)		19,205
Less: reclassification adjustment for gains realized in net income		39,353			(15,413	)		23,940

Net change for AFS investment securities — all other		(7,776	)		3,041			(4,735	)


Held-to-maturity (“HTM”) investment securities with OTTI:

Unrealized holding losses, net		(8,355	)		3,279			(5,076	)
Less: reclassification to income of unrealized holding losses		230			(90	)		140
Less: OTTI charges recognized in net income		(8,500	)		3,336			(5,164	)

Net change for HTM investment securities with OTTI		(85	)		33			(52	)


Reclassification to income of unrealized holding losses on investment securities previously transferred from AFS to HTM		1,698			(667	)		1,031


Net unrealized gains on investment securities		9,308			(3,650	)		5,658

Reclassification to income for amortization of gains on terminated cash flow hedges		(112	)		42			(70	)

Defined benefit plans liability adjustment		3,475			(1,364	)		2,111

	$	12,671			(4,972	)		7,699


	Three months ended March 31, 2010
	Before-tax			Income
	amount			taxes			Net
	(in thousands)
Unrealized gains (losses) on investment securities:

AFS investment securities with OTTI:

Unrealized holding losses, net	$	(29,487	)		11,574			(17,913	)
Less: OTTI charges recognized in net income		(26,802	)		10,483			(16,319	)

Net change for AFS investment securities with OTTI		(2,685	)		1,091			(1,594	)


AFS investment securities — all other:

Unrealized holding gains, net		131,379			(51,456	)		79,923
Less: reclassification adjustment for losses realized in net income		(145	)		44			(101	)

Net change for AFS investment securities — all other		131,524			(51,500	)		80,024


Reclassification to income of unrealized holding losses on investment securities previously transferred from AFS to HTM		2,347			(921	)		1,426


Net unrealized gains on investment securities		131,186			(51,330	)		79,856

Reclassification to income for amortization of gains on terminated cash flow hedges		(112	)		42			(70	)

Defined benefit plans liability adjustment		1,696			(666	)		1,030

	$	132,770			(51,954	)		80,816

Accumulated other comprehensive income (loss), net consisted of unrealized gains (losses) as follows:


							Cash			Defined
	Investment securities						flow			benefit
	With OTTI			All other			hedges			plans			Total
	(in thousands)
Balance — January 1, 2011	$	(87,053	)		2,332			393			(120,892	)		(205,220	)

Net gain (loss) during period		9,362			(3,704	)		(70	)		2,111			7,699


Balance — March 31, 2011	$	(77,691	)		(1,372	)		323			(118,781	)		(197,521	)


Balance — January 1, 2010	$	(76,772	)		(142,853	)		674			(117,046	)		(335,997	)

Net gain (loss) during period		(1,594	)		81,450			(70	)		1,030			80,816


Balance — March 31, 2010	$	(78,366	)		(61,403	)		604			(116,016	)		(255,181	)

Derivative financial instruments

3 Months Ended

Mar. 31, 2011

Derivative financial instruments [Abstract]

Derivative financial instruments

10. Derivative financial instruments

As part of managing interest rate risk, the Company enters into interest rate swap agreements to modify the repricing characteristics of certain portions of the Company’s portfolios of earning assets and interest-bearing liabilities. The Company designates interest rate swap agreements utilized in the management of interest rate risk as either fair value hedges or cash flow hedges. Interest rate swap agreements are generally entered into with counterparties that meet established credit standards and most contain master netting and collateral provisions protecting the at-risk party. Based on adherence to the Company’s credit standards and the presence of the netting and collateral provisions, the Company believes that the credit risk inherent in these contracts is not significant as of March 31, 2011.

The net effect of interest rate swap agreements was to increase net interest income by $10 million and $11 million for the three months ended March 31, 2011 and 2010, respectively. Information about interest rate swap agreements entered into for interest rate risk management purposes summarized by type of financial instrument the swap agreements were intended to hedge follows:


					Weighted-
	Notional		Average		average rate
	amount		maturity		Fixed			Variable
	(in thousands)		(in years)
March 31, 2011
Fair value hedges:
Fixed rate long-term borrowings (a)	$	900,000		6.1		6.07	%		1.85	%


December 31, 2010
Fair value hedges:
Fixed rate long-term borrowings (a)	$	900,000		6.4		6.07	%		1.84	%


(a)		Under the terms of these agreements, the Company receives settlement amounts at a fixed rate and pays at a variable rate.

The Company utilizes commitments to sell residential and commercial real estate loans to hedge the exposure to changes in the fair value of real estate loans held for sale. Such commitments have generally been designated as fair value hedges. The Company also utilizes commitments to sell real estate loans to offset the exposure to changes in fair value of certain commitments to originate real estate loans for sale.

Derivative financial instruments used for trading purposes included interest rate contracts, foreign exchange and other option contracts, foreign exchange forward and spot contracts, and financial futures. Interest rate contracts entered into for trading purposes had notional values of $12.3 billion and $12.8 billion at March 31, 2011 and December 31, 2010, respectively. The notional amounts of foreign currency and other option and futures contracts entered into for trading purposes aggregated $982 million and $769 million at March 31, 2011 and December 31, 2010, respectively.

Information about the fair values of derivative instruments in the Company’s consolidated balance sheet and consolidated statement of income follows:


	Asset derivatives				Liability derivatives
	Fair value				Fair value
	March 31,		December 31,		March 31,		December 31,
	2011		2010		2011		2010
	(in thousands)
Derivatives designated and qualifying as hedging instruments
Fair value hedges:
Interest rate swap agreements (a)	$	84,232		96,637	$	—		—
Commitments to sell real estate loans (a)		213		4,880		858		1,062

		84,445		101,517		858		1,062

Derivatives not designated and qualifying as hedging instruments
Mortgage-related commitments to originate real estate loans for sale (a)		16,267		2,827		120		583
Commitments to sell real estate loans (a)		1,281		10,322		3,135		1,962
Trading:
Interest rate contracts (b)		306,305		345,632		282,387		321,461
Foreign exchange and other option and futures contracts (b)		21,327		11,267		21,543		11,761

		345,180		370,048		307,185		335,767


Total derivatives	$	429,625		471,565	$	308,043		336,829


(a)		Asset derivatives are reported in other assets and liability derivatives are reported in other liabilities.

(b)		Asset derivatives are reported in trading account assets and liability derivatives are reported in other liabilities.


	Amount of unrealized gain (loss) recognized
	Three months ended					Three months ended
	March 31, 2011					March 31, 2010
	Derivative			Hedged item		Derivative			Hedged item
	(in thousands)
Derivatives in fair value hedging relationships

Interest rate swap agreements:
Fixed rate time deposits (a)	$	—			—	$	(199	)		199
Fixed rate long-term borrowings (a)		(12,405	)		12,048		12,470			(11,981	)


Total	$	(12,405	)		12,048	$	12,271			(11,782	)


Derivatives not designated as hedging instruments

Trading:
Interest rate contracts (b)	$	475				$	(614	)
Foreign exchange and other option and futures contracts (b)		(548	)				342


Total	$	(73	)			$	(272	)


(a)		Reported as other revenues from operations.

(b)		Reported as trading account and foreign exchange gains.

In addition, the Company also has commitments to sell and commitments to originate residential and commercial real estate loans that are considered derivatives. The Company designates certain of the commitments to sell real estate loans as fair value hedges of real estate loans held for sale. The Company also utilizes commitments to sell real estate loans to offset the exposure to changes in the fair value of certain commitments to originate real estate loans for sale. As a result of these activities, net unrealized pre-tax gains related to hedged loans held for sale, commitments to originate loans for sale and commitments to sell loans were approximately $19 million and $17 million at March 31, 2011 and December 31, 2010, respectively. Changes in unrealized gains and losses are included in mortgage banking revenues and, in general, are realized in subsequent periods as the related loans are sold and commitments satisfied.

The aggregate fair value of derivative financial instruments in a net liability position at March 31, 2011 for which the Company was required to post collateral was $174 million. The fair value of collateral posted for such instruments was $159 million.

The Company’s credit exposure with respect to the estimated fair value as of March 31, 2011 of interest rate swap agreements used for managing interest rate risk has been substantially mitigated through master netting agreements with trading account interest rate contracts with the same counterparties as well as counterparty postings of $60 million of collateral with the Company. Trading account interest rate swap agreements entered into with customers are subject to the Company’s credit standards and often contain collateral provisions.

Variable interest entities and asset securitizations	3 Months Ended
Variable interest entities and asset securitizations	Mar. 31, 2011
Variable interest entities and asset securitizations [Abstract]
Variable interest entities and asset securitizations	11. Variable interest entities and asset securitizations In accordance with GAAP, the Company determined that it was the primary beneficiary of a residential mortgage loan securitization trust considering its role as servicer and its retained subordinated interests in the trust. As a result, the Company has included the one-to-four family residential mortgage loans that were included in the trust in its consolidated financial statements. At March 31, 2011 and December 31, 2010, the carrying values of the loans in the securitization trust were $236 million and $265 million, respectively. The outstanding principal amount of mortgage-backed securities issued by the qualified special purpose trust that was held by parties unrelated to M&T at March 31, 2011 and December 31, 2010 was $37 million and $40 million, respectively. Because the transaction was non-recourse, the Company’s maximum exposure to loss as a result of its association with the trust at March 31, 2011 is limited to realizing the carrying value of the loans less the amount of the mortgage-backed securities held by third parties. As described in note 5, M&T has issued junior subordinated debentures payable to various trusts that have issued Capital Securities. M&T owns the common securities of those trust entities. The Company is not considered to be the primary beneficiary of those entities and, accordingly, the trusts are not included in the Company’s consolidated financial statements. At March 31, 2011 and December 31, 2010, the Company included the junior subordinated debentures as “long-term borrowings” in its consolidated balance sheet. The Company has recognized $34 million in other assets for its “investment” in the common securities of the trusts that will be concomitantly repaid to M&T by the respective trust from the proceeds of M&T’s repayment of the junior subordinated debentures associated with preferred capital securities described in note 5. The Company has invested as a limited partner in various real estate partnerships that collectively had total assets of approximately $1.2 billion and $1.1 billion at March 31, 2011 and December 31, 2010, respectively. Those partnerships generally construct or acquire properties for which the investing partners are eligible to receive certain federal income tax credits in accordance with government guidelines. Such investments may also provide tax deductible losses to the partners. The partnership investments also assist the Company in achieving its community reinvestment initiatives. As a limited partner, there is no recourse to the Company by creditors of the partnerships. However, the tax credits that result from the Company’s investments in such partnerships are generally subject to recapture should a partnership fail to comply with the respective government regulations. The Company’s maximum exposure to loss of its investments in such partnerships was $249 million, including $71 million of unfunded commitments, at March 31, 2011 and $258 million, including $81 million of unfunded commitments, at December 31, 2010. The Company has not provided financial or other support to the partnerships that was not contractually required. Management currently estimates that no material losses are probable as a result of the Company’s involvement with such entities. In accordance with the accounting provisions for variable interest entities, the Company, in its position as limited partner, does not direct the activities that most significantly impact the economic performance of the partnerships and, therefore, the partnership entities are not included in the Company’s consolidated financial statements.

Fair value measurements

3 Months Ended

Mar. 31, 2011

Fair value measurements [Abstract]

Fair value measurements

12. Fair value measurements

GAAP permits an entity to choose to measure eligible financial instruments and other items at fair value. The Company has not made any fair value elections at March 31, 2011.

Pursuant to GAAP, fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. A three-level hierarchy exists in GAAP for fair value measurements based upon the inputs to the valuation of an asset or liability.

	•		Level 1 — Valuation is based on quoted prices in active markets for identical assets and liabilities.

	•		Level 2 — Valuation is determined from quoted prices for similar assets or liabilities in active markets, quoted prices for identical or similar instruments in markets that are not active or by model-based techniques in which all significant inputs are observable in the market.

	•		Level 3 — Valuation is derived from model-based and other techniques in which at least one significant input is unobservable and which may be based on the Company’s own estimates about the assumptions that market participants would use to value the asset or liability.

When available, the Company attempts to use quoted market prices in active markets to determine fair value and classifies such items as Level 1 or Level 2. If quoted market prices in active markets are not available, fair value is often determined using model-based techniques incorporating various assumptions including interest rates, prepayment speeds and credit losses. Assets and liabilities valued using model-based techniques are classified as either Level 2 or Level 3, depending on the lowest level classification of an input that is considered significant to the overall valuation. The following is a description of the valuation methodologies used for the Company’s assets and liabilities that are measured on a recurring basis at estimated fair value.

Trading account assets and liabilities

Trading account assets and liabilities consist primarily of interest rate swap agreements and foreign exchange contracts with customers who require such services with offsetting positions with third parties to minimize the Company’s risk with respect to such transactions. The Company generally determines the fair value of its derivative trading account assets and liabilities using externally developed pricing models based on market observable inputs and therefore classifies such valuations as Level 2. Mutual funds held in connection with deferred compensation arrangements have been classified as Level 1 valuations. Valuations of investments in municipal and other bonds can generally be obtained through reference to quoted prices in less active markets for the same or similar securities or through model-based techniques in which all significant inputs are observable and, therefore, such valuations have been classified as Level 2.

Investment securities available for sale

The majority of the Company’s available-for-sale investment securities have been valued by reference to prices for similar securities or through model-based techniques in which all significant inputs are observable and, therefore, such valuations have been classified as Level 2. Certain investments in mutual funds and equity securities are actively traded and therefore have been classified as Level 1 valuations.

Trading activity in privately issued mortgage-backed securities has been limited. The markets for such securities were generally characterized by a sharp reduction of non-agency mortgage-backed securities issuances, a significant reduction in trading volumes and wide bid-ask spreads, all driven by the lack of market participants. Although estimated prices were generally obtained for such securities, the Company was significantly restricted in the level of market observable assumptions used in the valuation of its privately issued mortgage-backed securities portfolio. Specifically, market assumptions regarding credit adjusted cash flows and liquidity influences on discount rates were difficult to observe at the individual bond level. Because of the inactivity in the markets and the lack of observable valuation inputs, the Company has classified the valuation of privately issued mortgage-backed securities as Level 3.

GAAP provides guidance for estimating fair value when the volume and level of trading activity for an asset or liability have significantly decreased. The Company has concluded that there has been a significant decline in the volume and level of activity in the market for privately issued mortgage-backed securities. Therefore, the Company supplemented its determination of fair value for many of its privately issued mortgage-backed securities by obtaining pricing indications from two independent sources at March 31, 2011 and December 31, 2010. However, the Company could not readily ascertain that the basis of such valuations could be ascribed to orderly and observable trades in the market for privately issued residential mortgage-backed securities. As a result, the Company also performed internal modeling to estimate the cash flows and fair value of privately issued residential mortgage-backed securities with an amortized cost basis of $1.4 billion at March 31, 2011 and $1.5 billion at December 31, 2010. The Company’s internal modeling techniques included discounting estimated bond-specific cash flows using assumptions about cash flows associated with loans underlying each of the bonds, including estimates about the timing and amount of credit losses and prepayments. In estimating those cash flows, the Company used assumptions as to future delinquency, defaults and loss rates; including assumptions for further home price depreciation. Differences between internal model valuations and external pricing indications were generally considered to be reflective of the lack of liquidity in the market for privately issued mortgage-backed securities given the nature of the cash flow modeling performed in the Company’s assessment of value. To determine the point within the range of potential values that was most representative of fair value under current market conditions for each of the bonds, the Company computed values based on judgmentally applied weightings of the internal model valuations and the indications obtained from the average of the two independent pricing sources. Weightings applied to internal model valuations generally ranged from zero to 40% depending on bond structure and collateral type, with prices for bonds in non-senior tranches generally receiving lower weightings on the internal model results and senior bonds receiving a higher model weighting. At March 31, 2011, weighted-average reliance on internal model pricing for the bonds modeled was 34% with a 66% average weighting placed on the values provided by the independent sources. The Company concluded its estimate of fair value for the $1.4 billion of privately issued residential mortgage-backed securities to approximate $1.3 billion, which implies a weighted-average market yield based on reasonably likely cash flows of 8.3%. Other valuations of privately issued residential mortgage-backed securities were determined by reference to independent pricing sources without adjustment.

Included in collateralized debt obligations are securities backed by trust preferred securities issued by financial institutions and other entities. Given the severe disruption in the credit markets and lack of observable trade information, the Company could not obtain pricing indications for many of these securities from its two primary independent pricing sources. The Company, therefore, performed internal modeling to estimate the cash flows and fair value of its portfolio of securities backed by trust preferred securities at March 31, 2011 and December 31, 2010. The modeling techniques included discounting estimated cash flows using bond-specific assumptions about defaults, deferrals and prepayments of the trust preferred securities underlying each bond. The estimation of cash flows included assumptions as to future collateral defaults and related loss severities. The resulting cash flows were then discounted by reference to market yields observed in the single-name trust preferred securities market. At March 31, 2011, the total amortized cost and fair value of securities backed by trust preferred securities issued by financial institutions and other entities was $94 million and $114 million, respectively, and at December 31, 2010 were $95 million and $111 million, respectively. Privately issued mortgage-backed securities and securities backed by trust preferred securities issued by financial institutions and other entities constituted all of the available-for-sale investment securities classified as Level 3 valuations as of March 31, 2011 and December 31, 2010.

Real estate loans held for sale

The Company utilizes commitments to sell real estate loans to hedge the exposure to changes in fair value of real estate loans held for sale. The carrying value of hedged real estate loans held for sale includes changes in estimated fair value during the hedge period. Typically, the Company attempts to hedge real estate loans held for sale from the date of close through the sale date. The fair value of hedged real estate loans held for sale is generally calculated by reference to quoted prices in secondary markets for commitments to sell real estate loans with similar characteristics and, accordingly, such loans have been classified as a Level 2 valuation.

Commitments to originate real estate loans for sale and commitments to sell real estate loans

The Company enters into various commitments to originate real estate loans for sale and commitments to sell real estate loans. Such commitments are considered to be derivative financial instruments and, therefore, are carried at estimated fair value on the consolidated balance sheet. The estimated fair values of such commitments were generally calculated by reference to quoted prices in secondary markets for commitments to sell real estate loans to certain government-sponsored entities and other parties. The fair valuations of commitments to sell real estate loans generally result in a Level 2 classification. The estimated fair value of commitments to originate real estate loans for sale are adjusted to reflect the Company’s anticipated commitment expirations. Estimated commitment expirations are considered a significant unobservable input, which results in a Level 3 classification. The Company includes the expected net future cash flows related to the associated servicing of the loan in the fair value measurement of a derivative loan commitment. The estimated value ascribed to the expected net future servicing cash flows is also considered a significant unobservable input contributing to the Level 3 classification of commitments to originate real estate loans for sale.

Interest rate swap agreements used for interest rate risk management

The Company utilizes interest rate swap agreements as part of the management of interest rate risk to modify the repricing characteristics of certain portions of its portfolios of earning assets and interest-bearing liabilities. The Company generally determines the fair value of its interest rate swap agreements using externally developed pricing models based on market observable inputs and therefore classifies such valuations as Level 2. The Company has considered counterparty credit risk in the valuation of its interest rate swap assets and has considered its own credit risk in the valuation of its interest rate swap liabilities.

The following tables present assets and liabilities at March 31, 2011 and December 31, 2010 measured at estimated fair value on a recurring basis:


	Fair value
	measurements at
	March 31,
	2011		Level 1 (a)		Level 2 (a)		Level 3
	(in thousands)
Trading account assets	$	413,737		54,843		358,894		—
Investment securities available for sale:
U.S. Treasury and federal agencies		39,139		—		39,139		—
Obligations of states and political subdivisions		59,390		—		59,390		—
Mortgage-backed securities:
Government issued or guaranteed		2,839,861		—		2,839,861		—
Privately issued residential		1,391,878		—		—		1,391,878
Privately issued commercial		20,467		—		—		20,467
Collateralized debt obligations		114,265		—		—		114,265
Other debt securities		306,549		—		306,549		—
Equity securities		83,435		71,324		12,111		—

		4,854,984		71,324		3,257,050		1,526,610


Real estate loans held for sale		188,573		—		188,573		—
Other assets (b)		101,993		—		85,726		16,267

Total assets	$	5,559,287		126,167		3,890,243		1,542,877


Trading account liabilities	$	303,930		—		303,930		—
Other liabilities (b)		4,113		—		3,993		120

Total liabilities	$	308,043		—		307,923		120


	Fair value
	measurements at
	December 31,
	2010		Level 1 (a)		Level 2 (a)		Level 3
	(in thousands)
Trading account assets	$	523,834		53,032		470,802		—
Investment securities available for sale:
U.S. Treasury and federal agencies		63,434		—		63,434		—
Obligations of states and political subdivisions		60,425		—		60,425		—
Mortgage-backed securities:
Government issued or guaranteed		3,306,241		—		3,306,241		—
Privately issued residential		1,435,561		—		—		1,435,561
Privately issued commercial		22,407		—		—		22,407
Collateralized debt obligations		110,756		—		—		110,756
Other debt securities		298,900		—		298,900		—
Equity securities		115,768		106,872		8,896		—

		5,413,492		106,872		3,737,896		1,568,724


Real estate loans held for sale		544,567		—		544,567		—
Other assets (b)		114,666		—		111,839		2,827

Total assets	$	6,596,559		159,904		4,865,104		1,571,551


Trading account liabilities	$	333,222		—		333,222		—
Other liabilities (b)		3,607		—		3,024		583

Total liabilities	$	336,829		—		336,246		583


(a)		There were no significant transfers between Level 1 and Level 2 of the fair value hierarchy during the three months ended March 31, 2011 and 2010.

(b)		Comprised predominantly of interest rate swap agreements used for interest rate risk management (Level 2), commitments to sell real estate loans (Level 2) and commitments to originate real estate loans to be held for sale (Level 3).

The changes in Level 3 assets and liabilities measured at estimated fair value on a recurring basis during the three months ended March 31, 2011 were as follows:


																	Changes in
																	unrealized
			Total gains (losses)														gains (losses)
			realized/unrealized														included in
																	earnings
						Included in											related to
	Balance-					other						Transfer in			Balance-		assets still
	January 1,		Included			comprehensive						and/or out of			March 31,		held at
	2011		in earnings			income			Settlements			Level 3 (c)			2011		March 31, 2011
(in thousands)
Investment securities available for sale:
Privately issued residential mortgage-backed securities	$	1,435,561		(7,541	)(a)		61,085			(97,227	)		—			1,391,878		(7,541	)(a)
Privately issued commercial mortgage-backed securities		22,407		—			(82	)		(1,858	)		—			20,467		—
Collateralized debt obligations		110,756		—			3,834			(325	)		—			114,265		—

		1,568,724		(7,541	)		64,837			(99,410	)		—			1,526,610		(7,541	)
Other assets and other liabilities		2,244		20,444	(b)		—			—			(6,541	)		16,147		16,036	(b)

The changes in Level 3 assets and liabilities measured at estimated fair value on a recurring basis during the three months ended March 31, 2010 were as follows:


																	Changes in
																	unrealized
				Total gains (losses)													gains (losses)
				realized/unrealized													included in
																	earnings
							Included in										related to
	Balance-						other					Transfer in			Balance-		assets still
	January 1,			Included			comprehensive					and/or out of			March 31,		held at
	2010			in earnings			income		Settlements			Level 3 (c)			2010		March 31, 2010
(in thousands)
Investment securities available for sale:
Privately issued residential mortgage-backed securities	$	2,064,904			(26,447	)(a)		74,454		(93,322	)		(355,248	)(d)		1,664,341		(26,447	)(a)
Privately issued commercial mortgage-backed securities		25,166			—			2,073		(2,114	)		—			25,125		—
Collateralized debt obligations		115,346			(355	)(a)		10,895		(131	)		—			125,755		(355	)(a)
Other debt securities		420			—			35		—			—			455		—

		2,205,836			(26,802	)		87,457		(95,567	)		(355,248	)		1,815,676		(26,802	)

Other assets and other liabilities		(80	)		18,022	(b)		—		—			(9,771	)		8,171		7,630	(b)


(a)		Reported as an other-than-temporary impairment loss in the consolidated statement of income or as gain (loss) on bank investment securities.

(b)		Reported as mortgage banking revenues in the consolidated statement of income and includes the fair value of commitment issuances and expirations.

(c)		The Company’s policy for transfers between fair value levels is to recognize the transfer as of the actual date of the event or change in circumstances that caused the transfer.

(d)		As a result of the Company’s adoption of new accounting rules governing the consolidation of variable interest entities, effective January 1, 2010 the Company derecognized $355 million of available-for-sale investment securities previously classified as Level 3 measurements.

The Company is required, on a nonrecurring basis, to adjust the carrying value of certain assets or provide valuation allowances related to certain assets using fair value measurements. The more significant of those assets follow.

Loans

Loans are generally not recorded at fair value on a recurring basis. Periodically, the Company records nonrecurring adjustments to the carrying value of loans based on fair value measurements for partial charge-offs of the uncollectible portions of those loans. Nonrecurring adjustments also include certain impairment amounts for collateral-dependent loans when establishing the allowance for credit losses. Such amounts are generally based on the fair value of the underlying collateral supporting the loan and, as a result, the carrying value of the loan less the calculated valuation amount does not necessarily represent the fair value of the loan. Real estate collateral is typically valued using appraisals or other indications of value based on recent comparable sales of similar properties or assumptions generally observable in the marketplace and the related nonrecurring fair value measurement adjustments have generally been classified as Level 2, unless significant adjustments have been made to the valuation that are not readily observable by market participants. Estimates of fair value used for other collateral supporting commercial loans generally are based on assumptions not observable in the marketplace and therefore such valuations have been classified as Level 3. Loans subject to nonrecurring fair value measurement were $550 million at March 31, 2011 ($267 million and $283 million of which were classified as Level 2 and Level 3, respectively) and $793 million at March 31, 2010 ($471 million and $322 million of which were classified as Level 2 and Level 3, respectively). Changes in fair value recognized for partial charge-offs of loans and loan impairment reserves on loans held by the Company on March 31, 2011 and 2010 were decreases of $48 million and $58 million for the three-month periods ended March 31, 2011 and 2010, respectively.

Assets taken in foreclosure of defaulted loans

Assets taken in foreclosure of defaulted loans are primarily comprised of commercial and residential real property and are generally measured at the lower of cost or fair value less costs to sell. The fair value of the real property is generally determined using appraisals or other indications of value based on recent comparable sales of similar properties or assumptions generally observable in the marketplace, and the related nonrecurring fair value measurement adjustments have generally been classified as Level 2. Assets taken in foreclosure of defaulted loans subject to nonrecurring fair value measurement were $34 million and $17 million at March 31, 2011 and March 31, 2010, respectively. Changes in fair value recognized for those foreclosed assets held by the Company at March 31, 2011 were $9 million for the three months ended March 31, 2011. Changes in fair value recognized for those foreclosed assets held by the Company at March 31, 2010 were $10 million for the three months ended March 31, 2010.

Disclosures of fair value of financial instruments

With the exception of marketable securities, certain off-balance sheet financial instruments and one-to-four family residential mortgage loans originated for sale, the Company’s financial instruments are not readily marketable and market prices do not exist. The Company, in attempting to comply with the provisions of GAAP that require disclosures of fair value of financial instruments, has not attempted to market its financial instruments to potential buyers, if any exist. Since negotiated prices in illiquid markets depend greatly upon the then present motivations of the buyer and seller, it is reasonable to assume that actual sales prices could vary widely from any estimate of fair value made without the benefit of negotiations. Additionally, changes in market interest rates can dramatically impact the value of financial instruments in a short period of time. Additional information about the assumptions and calculations utilized follows.

The carrying amounts and estimated fair value for financial instrument assets (liabilities) are presented in the following table:


	March 31, 2011						December 31, 2010
	Carrying			Calculated			Carrying			Calculated
	amount			estimate			amount			estimate
	(in thousands)
Financial assets:
Cash and cash equivalents	$	982,305		$	982,305		$	933,755		$	933,755
Interest-bearing deposits at banks		100,101			100,101			101,222			101,222
Trading account assets		413,737			413,737			523,834			523,834
Investment securities		6,507,165			6,418,912			7,150,540			7,051,454
Loans and leases:
Commercial loans and leases		13,826,299			13,566,686			13,390,610			13,135,569
Commercial real estate loans		20,891,615			20,563,422			21,183,161			20,840,346
Residential real estate loans		6,154,960			5,876,173			5,928,056			5,699,028
Consumer loans		11,245,807			10,949,858			11,488,555			11,178,583
Allowance for credit losses		(903,703	)		—			(902,941	)		—

Loans and leases, net		51,214,978			50,956,139			51,087,441			50,853,526
Accrued interest receivable		220,922			220,922			202,182			202,182

Financial liabilities:
Noninterest-bearing deposits	$	(15,219,562	)	$	(15,219,562	)	$	(14,557,568	)	$	(14,557,568	)
Savings deposits and NOW accounts		(28,756,435	)		(28,756,435	)		(27,824,630	)		(27,824,630	)
Time deposits		(5,508,432	)		(5,548,229	)		(5,817,170	)		(5,865,779	)
Deposits at Cayman Islands office		(1,063,670	)		(1,063,670	)		(1,605,916	)		(1,605,916	)
Short-term borrowings		(504,676	)		(504,676	)		(947,432	)		(947,432	)
Long-term borrowings		(7,305,420	)		(7,442,997	)		(7,840,151	)		(7,937,397	)
Accrued interest payable		(95,762	)		(95,762	)		(71,954	)		(71,954	)
Trading account liabilities		(303,930	)		(303,930	)		(333,222	)		(333,222	)

Other financial instruments:
Commitments to originate real estate loans for sale	$	16,147		$	16,147		$	2,244		$	2,244
Commitments to sell real estate loans		(2,499	)		(2,499	)		12,178			12,178
Other credit-related commitments		(68,108	)		(68,108	)		(74,426	)		(74,426	)
Interest rate swap agreements used for interest rate risk management		84,232			84,232			96,637			96,637

The following assumptions, methods and calculations were used in determining the estimated fair value of financial instruments not measured at fair value in the consolidated balance sheet.

Cash and cash equivalents, interest-bearing deposits at banks, short-term borrowings, accrued interest receivable and accrued interest payable

Due to the nature of cash and cash equivalents and the near maturity of interest-bearing deposits at banks, short-term borrowings, accrued interest receivable and accrued interest payable, the Company estimated that the carrying amount of such instruments approximated estimated fair value.

Investment securities

Estimated fair values of investments in readily marketable securities were generally based on quoted market prices. Investment securities that were not readily marketable were assigned amounts based on estimates provided by outside parties or modeling techniques that relied upon discounted calculations of projected cash flows or, in the case of other investment securities, which include capital stock of the Federal Reserve Bank of New York and the Federal Home Loan Bank of New York, at an amount equal to the carrying amount.

Loans and leases

In general, discount rates used to calculate values for loan products were based on the Company’s pricing at the respective period end. A higher discount rate was assumed with respect to estimated cash flows associated with nonaccrual loans. Projected loan cash flows were adjusted for estimated credit losses. However, such estimates made by the Company may not be indicative of assumptions and adjustments that a purchaser of the Company’s loans and leases would seek.

Deposits

Pursuant to GAAP, the estimated fair value ascribed to noninterest-bearing deposits, savings deposits and NOW accounts must be established at carrying value because of the customers’ ability to withdraw funds immediately. Time deposit accounts are required to be revalued based upon prevailing market interest rates for similar maturity instruments. As a result, amounts assigned to time deposits were based on discounted cash flow calculations using prevailing market interest rates based on the Company’s pricing at the respective date for deposits with comparable remaining terms to maturity.

The Company believes that deposit accounts have a value greater than that prescribed by GAAP. The Company feels, however, that the value associated with these deposits is greatly influenced by characteristics of the buyer, such as the ability to reduce the costs of servicing the deposits and deposit attrition which often occurs following an acquisition.

Long-term borrowings

The amounts assigned to long-term borrowings were based on quoted market prices, when available, or were based on discounted cash flow calculations using prevailing market interest rates for borrowings of similar terms and credit risk.

Commitments to originate real estate loans for sale and commitments to sell real estate loans

Interest rate swap agreements used for interest rate risk management

The estimated fair value of interest rate swap agreements used for interest rate risk management represents the amount the Company would have expected to receive or pay to terminate such agreements.

Other commitments and contingencies

As described in note 13, in the normal course of business, various commitments and contingent liabilities are outstanding, such as loan commitments, credit guarantees and letters of credit. The Company’s pricing of such financial instruments is based largely on credit quality and relationship, probability of funding and other requirements. Loan commitments often have fixed expiration dates and contain termination and other clauses which provide for relief from funding in the event of significant deterioration in the credit quality of the customer. The rates and terms of the Company’s loan commitments, credit guarantees and letters of credit are competitive with other financial institutions operating in markets served by the Company. The Company believes that the carrying amounts, which are included in other liabilities, are reasonable estimates of the fair value of these financial instruments.

The Company does not believe that the estimated information presented herein is representative of the earnings power or value of the Company. The preceding analysis, which is inherently limited in depicting fair value, also does not consider any value associated with existing customer relationships nor the ability of the Company to create value through loan origination, deposit gathering or fee generating activities.

Many of the estimates presented herein are based upon the use of highly subjective information and assumptions and, accordingly, the results may not be precise. Management believes that fair value estimates may not be comparable between financial institutions due to the wide range of permitted valuation techniques and numerous estimates which must be made. Furthermore, because the disclosed fair value amounts were estimated as of the balance sheet date, the amounts actually realized or paid upon maturity or settlement of the various financial instruments could be significantly different.

Commitments and contingencies

3 Months Ended

Mar. 31, 2011

Commitments and contingencies [Abstract]

Commitments and contingencies

13. Commitments and contingencies

In the normal course of business, various commitments and contingent liabilities are outstanding. The following table presents the Company’s significant commitments. Certain of these commitments are not included in the Company’s consolidated balance sheet.


	March 31,		December 31,
	2011		2010
	(in thousands)
Commitments to extend credit Home equity lines of credit	$	6,274,649		6,281,366
Commercial real estate loans to be sold		422,511		72,930
Other commercial real estate and construction		1,779,514		1,672,006
Residential real estate loans to be sold		438,283		161,583
Other residential real estate		112,328		151,111
Commercial and other		8,816,887		8,332,199

Standby letters of credit		3,852,506		3,917,318

Commercial letters of credit		58,805		76,962

Financial guarantees and indemnification contracts		1,707,670		1,609,944

Commitments to sell real estate loans		889,631		734,696

Commitments to extend credit are agreements to lend to customers, generally having fixed expiration dates or other termination clauses that may require payment of a fee. Standby and commercial letters of credit are conditional commitments issued to guarantee the performance of a customer to a third party. Standby letters of credit generally are contingent upon the failure of the customer to perform according to the terms of the underlying contract with the third party, whereas commercial letters of credit are issued to facilitate commerce and typically result in the commitment being funded when the underlying transaction is consummated between the customer and a third party. The credit risk associated with commitments to extend credit and standby and commercial letters of credit is essentially the same as that involved with extending loans to customers and is subject to normal credit policies. Collateral may be obtained based on management’s assessment of the customer’s creditworthiness.

Financial guarantees and indemnification contracts are oftentimes similar to standby letters of credit and include mandatory purchase agreements issued to ensure that customer obligations are fulfilled, recourse obligations associated with sold loans, and other guarantees of customer performance or compliance with designated rules and regulations. Included in financial guarantees and indemnification contracts are loan principal amounts sold with recourse in conjunction with the Company’s involvement in the Fannie Mae Delegated Underwriting and Servicing program. The Company’s maximum credit risk for recourse associated with loans sold under this program totaled approximately $1.6 billion at each of March 31, 2011 and December 31, 2010.

Since many loan commitments, standby letters of credit, and guarantees and indemnification contracts expire without being funded in whole or in part, the contract amounts are not necessarily indicative of future cash flows.

The Company utilizes commitments to sell real estate loans to hedge exposure to changes in the fair value of real estate loans held for sale. Such commitments are considered derivatives and along with commitments to originate real estate loans to be held for sale are generally recorded in the consolidated balance sheet at estimated fair market value.

The Company has an agreement with the Baltimore Ravens of the National Football League whereby the Company obtained the naming rights to a football stadium in Baltimore, Maryland. Under the agreement, the Company is obligated to pay $5 million per year through 2013 and $6 million per year from 2014 through 2017.

The Company also has commitments under long-term operating leases.

The Company reinsures credit life and accident and health insurance purchased by consumer loan customers. The Company also enters into reinsurance contracts with third party insurance companies who insure against the risk of a mortgage borrower’s payment default in connection with certain mortgage loans originated by the Company. When providing reinsurance coverage, the Company receives a premium in exchange for accepting a portion of the insurer’s risk of loss. The outstanding loan principal balances reinsured by the Company were approximately $82 million at March 31, 2011. Assets of subsidiaries providing reinsurance that are available to satisfy claims totaled approximately $53 million at March 31, 2011. The amounts noted above are not necessarily indicative of losses which may ultimately be incurred. Such losses are expected to be substantially less because most loans are repaid by borrowers in accordance with the original loan terms. Management believes any reinsurance losses that may be payable by the Company will not be material to the Company’s consolidated financial position.

The Company is contractually obligated to repurchase previously sold residential real estate loans that do not ultimately meet investor sale criteria related to underwriting procedures or loan documentation. When required to do so, the Company may reimburse loan purchasers for losses incurred or may repurchase certain loans. The Company reduces residential mortgage banking revenues by an estimate for losses related to its obligations to loan purchasers. The amount of those charges is based on the volume of loans sold, the level of reimbursement requests received from loan purchasers and estimates of losses that may be associated with previously sold loans. At March 31, 2011, management believes that any remaining liability arising out of the Company’s obligation to loan purchasers is not material to the Company’s consolidated financial position.

M&T and its subsidiaries are subject in the normal course of business to various pending and threatened legal proceedings in which claims for monetary damages are asserted. Management, after consultation with legal counsel, does not anticipate that the aggregate ultimate liability arising out of litigation pending against M&T or its subsidiaries will be material to the Company’s consolidated financial position, but at the present time is not in a position to determine whether such litigation will have a material adverse effect on the Company’s consolidated results of operations in any future reporting period.

Segment information

3 Months Ended

Mar. 31, 2011

Segment information [Abstract]

Segment information

14. Segment information

Reportable segments have been determined based upon the Company’s internal profitability reporting system, which is organized by strategic business unit. Certain strategic business units have been combined for segment information reporting purposes where the nature of the products and services, the type of customer and the distribution of those products and services are similar. The reportable segments are Business Banking, Commercial Banking, Commercial Real Estate, Discretionary Portfolio, Residential Mortgage Banking and Retail Banking.

The financial information of the Company’s segments was compiled utilizing the accounting policies described in note 22 to the Company’s consolidated financial statements as of and for the year ended December 31, 2010. The management accounting policies and processes utilized in compiling segment financial information are highly subjective and, unlike financial accounting, are not based on authoritative guidance similar to GAAP. As a result, the financial information of the reported segments is not necessarily comparable with similar information reported by other financial institutions. As also described in note 22 to the Company’s 2010 consolidated financial statements, neither goodwill nor core deposit and other intangible assets (and the amortization charges associated with such assets) resulting from acquisitions of financial institutions have been allocated to the Company’s reportable segments, but are included in the “All Other” category. The Company does, however, assign such intangible assets to business units for purposes of testing for impairment.

Information about the Company’s segments is presented in the following table:


	Three months ended March 31
	2011								2010
			Inter-			Net						Inter-			Net
	Total		segment			income			Total			segment			income
	revenues(a)		revenues			(loss)			revenues(a)			revenues			(loss)
	(in thousands)
Business Banking	$	99,777		962			26,300			101,796			—			25,344
Commercial Banking		213,612		1,166			88,331			192,406			—			76,868
Commercial Real Estate		125,306		356			49,010			110,413			18			43,753
Discretionary Portfolio		42,483		(7,787	)		16,127			(12,233	)		(2,747	)		(16,162	)
Residential Mortgage Banking		57,848		10,307			4,785			63,117			8,197			595
Retail Banking		295,048		2,987			52,726			307,475			2,687			59,037
All Other		49,150		(7,991	)		(31,006	)		51,066			(8,155	)		(38,480	)

Total	$	883,224		—			206,273			814,040			—			150,955


	Average total assets
	Three months ended				Year ended
	March 31				December 31
	2011		2010		2010
	(in millions)
Business Banking	$	4,754		4,959		4,843
Commercial Banking		16,114		15,509		15,461
Commercial Real Estate		13,635		13,368		13,194
Discretionary Portfolio		13,931		14,571		14,690
Residential Mortgage Banking		2,045		2,222		2,217
Retail Banking		11,653		12,272		12,079
All Other		5,913		5,982		5,896

Total	$	68,045		68,883		68,380


(a)		Total revenues are comprised of net interest income and other income. Net interest income is the difference between taxable-equivalent interest earned on assets and interest paid on liabilities owed by a segment and a funding charge (credit) based on the Company’s internal funds transfer pricing and allocation methodology. Segments are charged a cost to fund any assets (e.g. loans) and are paid a funding credit for any funds provided (e.g. deposits). The taxable-equivalent adjustment aggregated $6,327,000 and $5,923,000 for the three-month periods ended March 31, 2011 and 2010, respectively, and is eliminated in “All Other” total revenues. Intersegment revenues are included in total revenues of the reportable segments. The elimination of intersegment revenues is included in the determination of “All Other” total revenues.

Relationship with Bayview Lending Group LLC and Bayview Financial Holdings, L.P.	3 Months Ended
	Mar. 31, 2011
Relationship With Other Entities [Abstract]
Relationship with Bayview Lending Group LLC and Bayview Financial Holdings, L.P.	15. Relationship with Bayview Lending Group LLC and Bayview Financial Holdings, L.P. M&T holds a 20% minority interest in Bayview Lending Group LLC (“BLG”), a privately-held commercial mortgage lender. M&T recognizes income or loss from BLG using the equity method of accounting. The carrying value of that investment was $212 million at March 31, 2011. Bayview Financial Holdings, L.P. (together with its affiliates, “Bayview Financial”), a privately-held specialty mortgage finance company, is BLG’s majority investor. In addition to their common investment in BLG, the Company and Bayview Financial conduct other business activities with each other. The Company has obtained loan servicing rights for small-balance commercial mortgage loans from BLG and Bayview Financial having outstanding principal balances of $5.1 billion and $5.2 billion at March 31, 2011 and December 31, 2010, respectively. Amounts recorded as capitalized servicing assets for such loans totaled $23 million at March 31, 2011 and $26 million at December 31, 2010. In addition, capitalized servicing rights at March 31, 2011 and December 31, 2010 also included $8 million and $9 million, respectively, for servicing rights that were obtained from Bayview Financial related to residential mortgage loans with outstanding principal balances of $3.5 billion at March 31, 2011 and $3.6 billion at December 31, 2010. Revenues from servicing residential and small-balance commercial mortgage loans obtained from BLG and Bayview Financial were $11 million and $12 million during the quarters ended March 31, 2011 and 2010, respectively. In addition, at March 31, 2011 and December 31, 2010, the Company held $20 million and $22 million, respectively, of collateralized mortgage obligations in its available-for-sale investment securities portfolio that were securitized by Bayview Financial. Finally, the Company held $300 million and $313 million of similar investment securities in its held-to-maturity portfolio at March 31, 2011 and December 31, 2010, respectively.

Significant Accounting Policies (Policies)	3 Months Ended
Significant Accounting Policies (Policies)	Mar. 31, 2011
Significant Accounting Policies (Policies) [Abstract]
Consolidation	The consolidated financial statements of M&T Bank Corporation (“M&T”) and subsidiaries (“the Company”) were compiled in accordance with generally accepted accounting principles (“GAAP”) using the accounting policies set forth in note 1 of Notes to Financial Statements included in the 2010 Annual Report. In the opinion of management, all adjustments necessary for a fair presentation have been made and were all of a normal recurring nature.

Acquisitions (Tables)

3 Months Ended

Mar. 31, 2011

Acquisitions (Tables) [Abstract]

Summary of merger-related expenses associated with the Bradford and Provident acquisitions


	(in thousands)
Salaries and employee benefits	$	7
Equipment and net occupancy		79
Printing, postage and supplies		147
Other costs of operations		4,062

	$	4,295

Investment securities (Tables)

3 Months Ended

Mar. 31, 2011

Investment securities (Tables) [Abstract]

Amortized cost and estimated fair value of investment securities


					Gross
	Amortized		Gross		unrealized		Estimated
	cost		unrealized gains		losses		fair value
	(in thousands)
March 31, 2011
Investment securities available for sale:
U.S. Treasury and federal agencies	$	38,531		758		150	$	39,139
Obligations of states and political subdivisions		59,010		442		62		59,390
Mortgage-backed securities:
Government issued or guaranteed		2,732,299		108,911		1,349		2,839,861
Privately issued residential		1,600,110		14,006		222,238		1,391,878
Privately issued commercial		23,232		—		2,765		20,467
Collateralized debt obligations		94,290		27,734		7,759		114,265
Other debt securities		306,870		29,980		30,301		306,549
Equity securities		78,118		7,121		1,804		83,435

		4,932,460		188,952		266,428		4,854,984


Investment securities held to maturity:
Obligations of states and political subdivisions		191,251		1,916		1,166		192,001
Mortgage-backed securities:
Government issued or guaranteed		758,611		11,743		—		770,354
Privately issued		299,780		—		100,746		199,034
Other debt securities		12,447		—		—		12,447

		1,262,089		13,659		101,912		1,173,836

Other securities		390,092		—		—		390,092

Total	$	6,584,641		202,611		368,340	$	6,418,912


			Gross		Gross
	Amortized		unrealized		unrealized		Estimated
	cost		gains		losses		fair value
	(in thousands)
December 31, 2010
Investment securities available for sale:
U.S. Treasury and federal agencies	$	61,772		1,680		18	$	63,434
Obligations of states and political subdivisions		59,921		561		57		60,425
Mortgage-backed securities:
Government issued or guaranteed		3,146,054		161,298		1,111		3,306,241
Privately issued residential		1,677,064		10,578		252,081		1,435,561
Privately issued commercial		25,357		—		2,950		22,407
Collateralized debt obligations		95,080		24,754		9,078		110,756
Other debt securities		310,017		26,883		38,000		298,900
Equity securities		119,112		5,098		8,442		115,768

		5,494,377		230,852		311,737		5,413,492


Investment securities held to maturity:
Obligations of states and political subdivisions		191,119		1,944		694		192,369
Mortgage-backed securities:
Government issued or guaranteed		808,108		14,061		—		822,169
Privately issued		312,537		—		114,397		198,140
Other debt securities		12,575		—		—		12,575

		1,324,339		16,005		115,091		1,225,253

Other securities		412,709		—		—		412,709

Total	$	7,231,425		246,857		426,828	$	7,051,454

Changes in credit losses associated with debt securities for which other-than-temporary impairment losses


	Three months ended
	March 31
	2011			2010
	(in thousands)
Beginning balance	$	327,912			284,513
Additions for credit losses not previously recognized		16,041			26,802
Reductions for increases in cash flows		(139	)		(169	)
Reductions for realized losses		(21,095	)		(3,129	)

Ending balance	$	322,719			308,017

Amortized cost and estimated fair value of debt securities by contractual maturity


	Amortized		Estimated
	cost		fair value
	(in thousands)
Debt securities available for sale:
Due in one year or less	$	7,437		7,532
Due after one year through five years		64,615		65,828
Due after five years through ten years		19,518		21,162
Due after ten years		407,131		424,821

		498,701		519,343
Mortgage-backed securities available for sale		4,355,641		4,252,206

	$	4,854,342		4,771,549


Debt securities held to maturity:
Due in one year or less	$	28,334		28,496
Due after one year through five years		14,306		14,719
Due after five years through ten years		140,556		140,782
Due after ten years		20,502		20,451

		203,698		204,448
Mortgage-backed securities held to maturity		1,058,391		969,388

	$	1,262,089		1,173,836

Investment securities in continuous unrealized loss position


	Less than 12 months					12 months or more
	Fair		Unrealized			Fair		Unrealized
	value		losses			value		losses
			(in thousands)
March 31, 2011
Investment securities available for sale:
U.S. Treasury and federal agencies	$	23,884		(150	)		—		—
Obligations of states and political subdivisions		3,488		(26	)		2,062		(36	)
Mortgage-backed securities:
Government issued or guaranteed		69,731		(1,311	)		3,212		(38	)
Privately issued residential		7,675		(523	)		1,014,944		(221,715	)
Privately issued commercial		—		—			20,467		(2,765	)
Collateralized debt obligations		15,011		(5,567	)		8,156		(2,192	)
Other debt securities		3,767		(68	)		96,364		(30,233	)
Equity securities		2,652		(510	)		1,254		(1,294	)

		126,208		(8,155	)		1,146,459		(258,273	)


Investment securities held to maturity:
Obligations of states and political subdivisions		86,929		(1,128	)		470		(38	)
Privately issued mortgage-backed securities		—		—			193,752		(100,746	)

		86,929		(1,128	)		194,222		(100,784	)

Total	$	213,137		(9,283	)		1,340,681		(359,057	)


December 31, 2010
Investment securities available for sale:
U.S. Treasury and federal agencies	$	27,289		(18	)		—		—
Obligations of states and political subdivisions		3,712		(18	)		2,062		(39	)

Mortgage-backed securities:
Government issued or guaranteed		68,507		(1,079	)		2,965		(32	)
Privately issued residential		61,192		(1,054	)		1,057,315		(251,027	)
Privately issued commercial		—		—			22,407		(2,950	)
Collateralized debt obligations		12,462		(6,959	)		6,004		(2,119	)
Other debt securities		2,134		(10	)		88,969		(37,990	)
Equity securities		5,326		(3,721	)		673		(4,721	)

		180,622		(12,859	)		1,180,395		(298,878	)


Investment securities held to maturity:
Obligations of states and political subdivisions		76,318		(638	)		467		(56	)
Privately issued mortgage-backed securities		—		—			198,140		(114,397	)

		76,318		(638	)		198,607		(114,453	)

Total	$	256,940		(13,497	)		1,379,002		(413,331	)

Loans and leases and the allowance for credit losses (Tables)

3 Months Ended

Mar. 31, 2011

Loans and leases and the allowance for credit losses (Tables) [Abstract]

Outstanding principal balance and the carrying amount of loans that is included in the consolidated balance sheet


	(in thousands)
Outstanding principal balance		$3,509,711
Carrying amount		3,184,469

Summary of current, past due and nonaccrual loans


			30-89
			Days		90 Days		Purchased
	Current		past due		past due		impaired		Nonaccrual		Total
					(in thousands)
March 31, 2011
Commercial, financial, leasing, etc.	$	13,605,508		24,626		21,055		1,922		173,188		13,826,299
Real estate:
Commercial		16,606,831		75,829		22,765		7,115		229,630		16,942,170
Residential builder and developer		886,832		21,859		4,493		68,442		320,295		1,301,921
Other commercial construction		2,421,823		97,824		17,327		2,013		108,537		2,647,524
Residential		4,983,032		194,594		195,241		6,897		178,109		5,557,873
Residential Alt-A		450,829		35,469		—		—		110,789		597,087
Consumer:
Home equity lines and loans		6,340,612		34,338		—		2,200		44,350		6,421,500
Automobile		2,545,546		33,784		—		—		29,839		2,609,169
Other		2,167,697		27,468		3,599		—		16,374		2,215,138

Total	$	50,008,710		545,791		264,480		88,589		1,211,111		52,118,681


			30-89
			Days		90 Days		Purchased
	Current		past due		past due		impaired		Nonaccrual		Total
	(in thousands)
December 31, 2010
Commercial, financial, leasing, etc.	$	13,088,887		96,087		16,647		2,250		186,739		13,390,610
Real estate:
Commercial		16,589,240		89,906		35,338		8,275		209,031		16,931,790
Residential builder and developer		891,764		30,805		9,763		72,710		346,448		1,351,490
Other commercial construction		2,723,399		36,420		11,323		2,098		126,641		2,899,881
Residential		4,699,711		229,641		192,276		9,320		172,729		5,303,677
Residential Alt-A		475,236		42,674		—		—		106,469		624,379
Consumer:
Home equity lines and loans		6,472,563		38,367		—		2,366		43,055		6,556,351
Automobile		2,608,230		44,604		—		—		31,892		2,684,726
Other		2,190,353		36,689		4,246		—		16,190		2,247,478

Total	$	49,739,383		645,193		269,593		97,019		1,239,194		51,990,382

Changes in the allowance for credit losses


	Commercial,
	Financial,					Real Estate
	Leasing, etc.			Commercial			Residential			Consumer			Unallocated		Total
	(in thousands)
Beginning balance	$	212,579			400,562			86,351			133,067			70,382		902,941
Provision for credit losses		14,942			14,775			15,841			27,764			1,678		75,000
Net charge-offs
Charge-offs		(14,027	)		(24,579	)		(16,167	)		(28,321	)		—		(83,094	)
Recoveries		2,165			349			1,501			4,841			—		8,856

Net charge-offs		(11,862	)		(24,230	)		(14,666	)		(23,480	)		—		(74,238	)

Ending balance	$	215,659			391,107			87,526			137,351			72,060		903,703

Allowance for credit Losses


	(in thousands)
Beginning balance	$	878,022
Provision for credit losses		105,000
Consolidation of loan securitization trusts		2,752
Net charge-offs
Charge-offs		(106,039	)
Recoveries		11,530

Net charge-offs		(94,509	)

Ending balance	$	891,265

Impaired loans and leases


	March 31, 2011						December 31, 2010
			Unpaid						Unpaid
	Recorded		principal		Related		Recorded		principal		Related
	investment		balance		allowance		investment		balance		allowance
	(in thousands)
With an allowance recorded:
Commercial, financial, leasing, etc.	$	102,977		153,773		33,363		121,744		170,888		40,909
Real estate:
Commercial		131,923		162,211		26,629		110,975		140,015		17,393
Residential builder and developer		250,433		304,636		65,578		263,545		295,031		78,597
Other commercial construction		84,617		110,488		12,839		80,934		85,432		22,067
Residential		83,405		101,223		3,945		73,006		85,279		3,375
Residential Alt-A		173,091		184,022		35,000		180,665		191,445		36,000
Consumer:
Home equity lines and loans		11,895		13,544		2,423		11,799		13,378		2,227
Automobile		59,465		59,465		12,774		58,858		58,858		12,597
Other		3,170		3,170		786		2,978		2,978		768

		900,976		1,092,532		193,337		904,504		1,043,304		213,933


With no related allowance recorded:
Commercial, financial, leasing, etc.		70,829		92,904		—		65,827		86,332		—
Real estate:
Commercial		101,076		120,472		—		101,939		116,316		—
Residential builder and developer		108,764		150,480		—		100,799		124,383		—
Other commercial construction		25,893		31,865		—		46,656		50,496		—
Residential		4,276		6,443		—		5,035		7,723		—
Residential Alt-A		29,285		50,272		—		28,967		47,879		—

		340,123		452,436		—		349,223		433,129		—


Total:
Commercial, financial, leasing, etc.		173,806		246,677		33,363		187,571		257,220		40,909
Real estate:
Commercial		232,999		282,683		26,629		212,914		256,331		17,393
Residential builder and developer		359,197		455,116		65,578		364,344		419,414		78,597
Other commercial construction		110,510		142,353		12,839		127,590		135,928		22,067
Residential		87,681		107,666		3,945		78,041		93,002		3,375
Residential Alt-A		202,376		234,294		35,000		209,632		239,324		36,000
Consumer:
Home equity lines and loans		11,895		13,544		2,423		11,799		13,378		2,227
Automobile		59,465		59,465		12,774		58,858		58,858		12,597
Other		3,170		3,170		786		2,978		2,978		768

Total	$	1,241,099		1,544,968		193,337		1,253,727		1,476,433		213,933

Interest income recognized on loans


	Three months ended						Three months ended
	March 31, 2011						March 31, 2010
			Interest income						Interest income
			recognized						recognized
	Average						Average
	recorded				Cash		recorded				Cash
	investment		Total		basis		investment		Total		basis
	(in thousands)
Commercial, financial, leasing, etc.	$	184,546		1,007		1,001		331,564		455		455
Real estate:
Commercial		221,601		384		342		289,470		371		371
Residential builder and developer		362,129		527		130		321,822		44		44
Other commercial construction		126,054		510		321		55,297		384		384
Residential		83,527		1,034		596		45,822		532		349
Residential Alt-A		205,632		1,995		551		226,878		2,183		438
Consumer:
Home equity lines and loans		12,076		161		26		12,491		192		38
Automobile		58,863		984		296		50,253		861		348
Other		3,031		57		6		3,236		66		16

Total	$	1,257,459		6,659		3,269		1,336,833		5,088		2,443

Summary of Loan grades


			Real Estate
	Commercial,				Residential		Other
	Financial,				Builder and		Commercial
	Leasing, etc.		Commercial		Developer		Construction
			(in thousands)
March 31, 2011
Pass	$	12,909,951		15,752,006		676,164		2,090,831
Criticized accrual		743,160		960,534		305,462		448,156
Criticized nonaccrual		173,188		229,630		320,295		108,537

Total	$	13,826,299		16,942,170		1,301,921		2,647,524


December 31, 2010
Pass	$	12,371,138		15,831,104		693,110		2,253,589
Criticized accrual		832,733		891,655		311,932		519,651
Criticized nonaccrual		186,739		209,031		346,448		126,641

Total	$	13,390,610		16,931,790		1,351,490		2,899,881

Allocation of allowance for credit losses on the basis of the Company's impairment methodology


	Commercial,
	Financial,		Real Estate
	Leasing, etc.		Commercial		Residential		Consumer		Total
	(in thousands)
March 31, 2011
Individually evaluated for impairment	$	33,211		101,993		38,000		15,686	$	188,890
Collectively evaluated for impairment		182,296		286,061		48,581		121,368		638,306
Purchased impaired		152		3,053		945		297		4,447

Allocated	$	215,659		391,107		87,526		137,351		831,643

Unallocated										72,060


Total									$	903,703


December 31, 2010
Individually evaluated for impairment	$	40,459		114,082		39,000		15,492	$	209,033
Collectively evaluated for impairment		171,670		282,505		46,976		117,475		618,626
Purchased impaired		450		3,975		375		100		4,900

Allocated	$	212,579		400,562		86,351		133,067		832,559

Unallocated										70,382


Total									$	902,941

Recorded investment in loans and leases on the basis of the Company's impairment methodology


	Commercial,
	Financial,		Real Estate
	Leasing, etc.		Commercial		Residential		Consumer		Total
	(in thousands)
March 31, 2011
Individually evaluated for impairment	$	173,188		658,462		285,106		72,330	$	1,189,086
Collectively evaluated for impairment		13,651,189		20,155,583		5,862,957		11,171,277		50,841,006
Purchased impaired		1,922		77,570		6,897		2,200		88,589


Total	$	13,826,299		20,891,615		6,154,960		11,245,807	$	52,118,681


December 31, 2010
Individually evaluated for impairment	$	186,739		682,120		286,612		72,082	$	1,227,553
Collectively evaluated for impairment		13,201,621		20,417,958		5,632,124		11,414,107		50,665,810
Purchased impaired		2,250		83,083		9,320		2,366		97,019


Total	$	13,390,610		21,183,161		5,928,056		11,488,555	$	51,990,382

Shareholders' Equity (Tables)

3 Months Ended

Mar. 31, 2011

Shareholders Equity (Tables) [Abstract]

Issued and outstanding preferred stock

Carrying

issued and

value

outstanding

March 31, 2011

December 31, 2010

(dollars in thousands)

Series A (a)

Fixed Rate Cumulative Perpetual

600,000

580,203

578,630

Preferred Stock, Series A, $1,000 liquidation preference per share, 600,000 shares authorized

Series B (b)

Series B Mandatory Convertible

26,500

Non-cumulative Preferred Stock, $1,000 liquidation preference per share, 26,500 shares authorized

Series C (a)(c)

Fixed Rate Cumulative Perpetual

151,500

136,682

135,527

Preferred Stock, Series C, $1,000 liquidation preference per share, 151,500 shares authorized


(a)		Shares were issued as part of the Troubled Asset Relief Program — Capital Purchase Program of the U.S. Department of Treasury (“U.S. Treasury”). Cash proceeds were allocated between the preferred stock and a ten-year warrant to purchase M&T common stock (Series A — 1,218,522 common shares at $73.86 per share, Series C — 407,542 common shares at $55.76 per share). Dividends, if declared, will accrue and be paid quarterly at a rate of 5% per year for the first five years following the original 2008 issuance dates and thereafter at a rate of 9% per year. The agreement with the U.S. Treasury contains limitations on certain actions of M&T, including the payment of quarterly cash dividends on M&T’s common stock in excess of $.70 per share, the repurchase of its common stock during the first three years of the agreement, and the amount and nature of compensation arrangements for certain of the Company’s officers.

(b)		Shares were assumed in an acquisition and a new Series B Preferred Stock was designated. Pursuant to their terms, the shares of Series B Preferred Stock were converted into 433,144 shares of M&T common stock on April 1, 2011. The preferred stock had a stated dividend rate of 10% per year.

(c)		Shares were assumed in an acquisition and a new Series C Preferred Stock was designated.

Pension plans and other postretirement benefits (Tables)

3 Months Ended

Mar. 31, 2011

Pension plans and other postretirement benefits (Tables) [Abstract]

Net periodic benefit cost for defined benefit plans


							Other
	Pension						postretirement
	benefits						benefits
	Three months ended March 31
	2011			2010			2011		2010
	(in thousands)
Service cost	$	5,300			4,875			125		100
Interest cost on projected benefit obligation		12,150			12,029			775		780
Expected return on plan assets		(12,700	)		(12,788	)		—		—
Amortization of prior service cost		(1,650	)		(1,650	)		25		25
Amortization of net actuarial loss		5,100			3,321			—		—


Net periodic benefit cost	$	8,200			5,787			925		905

Earnings per common share (Tables)

3 Months Ended

Mar. 31, 2011

Earnings per common share (Tables) [Abstract]

Computations of basic earnings per common share


	Three months ended
	March 31
	2011			2010
	(in thousands,
	except per share)
Income available to common shareholders:

Net income	$	206,273			150,955
Less: Preferred stock dividends (a)		(10,498	)		(10,056	)
Amortization of preferred stock discount (a)		(2,753	)		(2,558	)

Net income available to common equity		193,022			138,341
Less: Income attributable to unvested stock-based compensation awards		(2,909	)		(1,913	)


Net income available to common shareholders	$	190,113			136,428

Weighted-average shares outstanding:

Common shares outstanding (including common stock issuable) and unvested stock-based compensation awards		120,992			119,324
Less: Unvested stock-based compensation awards		(1,791	)		(1,559	)


Weighted-average shares outstanding		119,201			117,765

Basic earnings per common share	$	1.59			1.16


(a)		Including impact of not as yet declared cumulative dividends.

Computations of diluted earnings per common share


	Three months ended
	March 31
	2011			2010
	(in thousands,
	except per share)

Net income available to common equity	$	193,022			138,341
Less: Income attributable to unvested stock-based compensation awards		(2,901	)		(1,910	)


Net income available to common shareholders		190,121			136,431

Adjusted weighted-average shares outstanding:

Common and unvested stock-based compensation awards		120,992			119,324
Less: Unvested stock-based compensation awards		(1,791	)		(1,559	)
Plus: Incremental shares from assumed conversion of stock-based compensation awards and convertible preferred stock		651			491


Adjusted weighted-average shares outstanding		119,852			118,256

Diluted earnings per common share	$	1.59			1.15

Comprehensive income (Tables)

3 Months Ended

Mar. 31, 2011

Comprehensive income (Tables) [Abstract]

Components of other comprehensive income (loss)


	Three months ended March 31, 2011
	Before-tax			Income
	amount			taxes			Net
	(in thousands)
Unrealized gains (losses) on investment securities:

Available-for-sale (“AFS”) investment securities with other-than-temporary impairment (“OTTI”):

Unrealized holding gains, net	$	7,930			(3,108	)		4,822
Less: OTTI charges recognized in net income		(7,541	)		2,949			(4,592	)

Net change for AFS investment securities with OTTI		15,471			(6,057	)		9,414


AFS investment securities — all other:

Unrealized holding gains, net		31,577			(12,372	)		19,205
Less: reclassification adjustment for gains realized in net income		39,353			(15,413	)		23,940

Net change for AFS investment securities — all other		(7,776	)		3,041			(4,735	)


Held-to-maturity (“HTM”) investment securities with OTTI:

Unrealized holding losses, net		(8,355	)		3,279			(5,076	)
Less: reclassification to income of unrealized holding losses		230			(90	)		140
Less: OTTI charges recognized in net income		(8,500	)		3,336			(5,164	)

Net change for HTM investment securities with OTTI		(85	)		33			(52	)


Reclassification to income of unrealized holding losses on investment securities previously transferred from AFS to HTM		1,698			(667	)		1,031


Net unrealized gains on investment securities		9,308			(3,650	)		5,658

Reclassification to income for amortization of gains on terminated cash flow hedges		(112	)		42			(70	)

Defined benefit plans liability adjustment		3,475			(1,364	)		2,111

	$	12,671			(4,972	)		7,699


	Three months ended March 31, 2010
	Before-tax			Income
	amount			taxes			Net
	(in thousands)
Unrealized gains (losses) on investment securities:

AFS investment securities with OTTI:

Unrealized holding losses, net	$	(29,487	)		11,574			(17,913	)
Less: OTTI charges recognized in net income		(26,802	)		10,483			(16,319	)

Net change for AFS investment securities with OTTI		(2,685	)		1,091			(1,594	)


AFS investment securities — all other:

Unrealized holding gains, net		131,379			(51,456	)		79,923
Less: reclassification adjustment for losses realized in net income		(145	)		44			(101	)

Net change for AFS investment securities — all other		131,524			(51,500	)		80,024


Reclassification to income of unrealized holding losses on investment securities previously transferred from AFS to HTM		2,347			(921	)		1,426


Net unrealized gains on investment securities		131,186			(51,330	)		79,856

Reclassification to income for amortization of gains on terminated cash flow hedges		(112	)		42			(70	)

Defined benefit plans liability adjustment		1,696			(666	)		1,030

	$	132,770			(51,954	)		80,816

Accumulated other comprehensive income (loss), net consisted of unrealized gains (losses)


							Cash			Defined
	Investment securities						flow			benefit
	With OTTI			All other			hedges			plans			Total
	(in thousands)
Balance — January 1, 2011	$	(87,053	)		2,332			393			(120,892	)		(205,220	)

Net gain (loss) during period		9,362			(3,704	)		(70	)		2,111			7,699


Balance — March 31, 2011	$	(77,691	)		(1,372	)		323			(118,781	)		(197,521	)


Balance — January 1, 2010	$	(76,772	)		(142,853	)		674			(117,046	)		(335,997	)

Net gain (loss) during period		(1,594	)		81,450			(70	)		1,030			80,816


Balance — March 31, 2010	$	(78,366	)		(61,403	)		604			(116,016	)		(255,181	)

Derivative financial instruments (Tables)

3 Months Ended

Mar. 31, 2011

Derivative financial instruments (Tables) [Abstract]

Information about interest rate swap agreements


					Weighted-
	Notional		Average		average rate
	amount		maturity		Fixed			Variable
	(in thousands)		(in years)
March 31, 2011
Fair value hedges:
Fixed rate long-term borrowings (a)	$	900,000		6.1		6.07	%		1.85	%


December 31, 2010
Fair value hedges:
Fixed rate long-term borrowings (a)	$	900,000		6.4		6.07	%		1.84	%


(a)		Under the terms of these agreements, the Company receives settlement amounts at a fixed rate and pays at a variable rate.

Information about fair values of derivative instruments in consolidated balance sheet


	Asset derivatives				Liability derivatives
	Fair value				Fair value
	March 31,		December 31,		March 31,		December 31,
	2011		2010		2011		2010
	(in thousands)
Derivatives designated and qualifying as hedging instruments
Fair value hedges:
Interest rate swap agreements (a)	$	84,232		96,637	$	—		—
Commitments to sell real estate loans (a)		213		4,880		858		1,062

		84,445		101,517		858		1,062

Derivatives not designated and qualifying as hedging instruments
Mortgage-related commitments to originate real estate loans for sale (a)		16,267		2,827		120		583
Commitments to sell real estate loans (a)		1,281		10,322		3,135		1,962
Trading:
Interest rate contracts (b)		306,305		345,632		282,387		321,461
Foreign exchange and other option and futures contracts (b)		21,327		11,267		21,543		11,761

		345,180		370,048		307,185		335,767


Total derivatives	$	429,625		471,565	$	308,043		336,829


(a)		Asset derivatives are reported in other assets and liability derivatives are reported in other liabilities.

(b)		Asset derivatives are reported in trading account assets and liability derivatives are reported in other liabilities.

Information about fair values of derivative instruments in consolidated statement of income


	Amount of unrealized gain (loss) recognized
	Three months ended					Three months ended
	March 31, 2011					March 31, 2010
	Derivative			Hedged item		Derivative			Hedged item
	(in thousands)
Derivatives in fair value hedging relationships

Interest rate swap agreements:
Fixed rate time deposits (a)	$	—			—	$	(199	)		199
Fixed rate long-term borrowings (a)		(12,405	)		12,048		12,470			(11,981	)


Total	$	(12,405	)		12,048	$	12,271			(11,782	)


Derivatives not designated as hedging instruments

Trading:
Interest rate contracts (b)	$	475				$	(614	)
Foreign exchange and other option and futures contracts (b)		(548	)				342


Total	$	(73	)			$	(272	)


(a)		Reported as other revenues from operations.

(b)		Reported as trading account and foreign exchange gains.

Fair value measurements (Tables)

3 Months Ended

Mar. 31, 2011

Fair value measurements (Tables) [Abstract]

Assets and liabilities measured at estimated fair value on a recurring basis


	Fair value
	measurements at
	March 31,
	2011		Level 1 (a)		Level 2 (a)		Level 3
	(in thousands)
Trading account assets	$	413,737		54,843		358,894		—
Investment securities available for sale:
U.S. Treasury and federal agencies		39,139		—		39,139		—
Obligations of states and political subdivisions		59,390		—		59,390		—
Mortgage-backed securities:
Government issued or guaranteed		2,839,861		—		2,839,861		—
Privately issued residential		1,391,878		—		—		1,391,878
Privately issued commercial		20,467		—		—		20,467
Collateralized debt obligations		114,265		—		—		114,265
Other debt securities		306,549		—		306,549		—
Equity securities		83,435		71,324		12,111		—

		4,854,984		71,324		3,257,050		1,526,610


Real estate loans held for sale		188,573		—		188,573		—
Other assets (b)		101,993		—		85,726		16,267

Total assets	$	5,559,287		126,167		3,890,243		1,542,877


Trading account liabilities	$	303,930		—		303,930		—
Other liabilities (b)		4,113		—		3,993		120

Total liabilities	$	308,043		—		307,923		120


	Fair value
	measurements at
	December 31,
	2010		Level 1 (a)		Level 2 (a)		Level 3
	(in thousands)
Trading account assets	$	523,834		53,032		470,802		—
Investment securities available for sale:
U.S. Treasury and federal agencies		63,434		—		63,434		—
Obligations of states and political subdivisions		60,425		—		60,425		—
Mortgage-backed securities:
Government issued or guaranteed		3,306,241		—		3,306,241		—
Privately issued residential		1,435,561		—		—		1,435,561
Privately issued commercial		22,407		—		—		22,407
Collateralized debt obligations		110,756		—		—		110,756
Other debt securities		298,900		—		298,900		—
Equity securities		115,768		106,872		8,896		—

		5,413,492		106,872		3,737,896		1,568,724


Real estate loans held for sale		544,567		—		544,567		—
Other assets (b)		114,666		—		111,839		2,827

Total assets	$	6,596,559		159,904		4,865,104		1,571,551


Trading account liabilities	$	333,222		—		333,222		—
Other liabilities (b)		3,607		—		3,024		583

Total liabilities	$	336,829		—		336,246		583


(a)		There were no significant transfers between Level 1 and Level 2 of the fair value hierarchy during the three months ended March 31, 2011 and 2010.

(b)		Comprised predominantly of interest rate swap agreements used for interest rate risk management (Level 2), commitments to sell real estate loans (Level 2) and commitments to originate real estate loans to be held for sale (Level 3).

Changes in Level 3 assets and liabilities measured at estimated fair value on a recurring basis


																	Changes in
																	unrealized
			Total gains (losses)														gains (losses)
			realized/unrealized														included in
																	earnings
						Included in											related to
	Balance-					other						Transfer in			Balance-		assets still
	January 1,		Included			comprehensive						and/or out of			March 31,		held at
	2011		in earnings			income			Settlements			Level 3 (c)			2011		March 31, 2011
(in thousands)
Investment securities available for sale:
Privately issued residential mortgage-backed securities	$	1,435,561		(7,541	)(a)		61,085			(97,227	)		—			1,391,878		(7,541	)(a)
Privately issued commercial mortgage-backed securities		22,407		—			(82	)		(1,858	)		—			20,467		—
Collateralized debt obligations		110,756		—			3,834			(325	)		—			114,265		—

		1,568,724		(7,541	)		64,837			(99,410	)		—			1,526,610		(7,541	)
Other assets and other liabilities		2,244		20,444	(b)		—			—			(6,541	)		16,147		16,036	(b)


																	Changes in
																	unrealized
				Total gains (losses)													gains (losses)
				realized/unrealized													included in
																	earnings
							Included in										related to
	Balance-						other					Transfer in			Balance-		assets still
	January 1,			Included			comprehensive					and/or out of			March 31,		held at
	2010			in earnings			income		Settlements			Level 3 (c)			2010		March 31, 2010
(in thousands)
Investment securities available for sale:
Privately issued residential mortgage-backed securities	$	2,064,904			(26,447	)(a)		74,454		(93,322	)		(355,248	)(d)		1,664,341		(26,447	)(a)
Privately issued commercial mortgage-backed securities		25,166			—			2,073		(2,114	)		—			25,125		—
Collateralized debt obligations		115,346			(355	)(a)		10,895		(131	)		—			125,755		(355	)(a)
Other debt securities		420			—			35		—			—			455		—

		2,205,836			(26,802	)		87,457		(95,567	)		(355,248	)		1,815,676		(26,802	)

Other assets and other liabilities		(80	)		18,022	(b)		—		—			(9,771	)		8,171		7,630	(b)


(a)		Reported as an other-than-temporary impairment loss in the consolidated statement of income or as gain (loss) on bank investment securities.

(b)		Reported as mortgage banking revenues in the consolidated statement of income and includes the fair value of commitment issuances and expirations.

(c)		The Company’s policy for transfers between fair value levels is to recognize the transfer as of the actual date of the event or change in circumstances that caused the transfer.

(d)		As a result of the Company’s adoption of new accounting rules governing the consolidation of variable interest entities, effective January 1, 2010 the Company derecognized $355 million of available-for-sale investment securities previously classified as Level 3 measurements.

Carrying amounts and estimated fair value for financial instrument assets(liabilities)


	March 31, 2011						December 31, 2010
	Carrying			Calculated			Carrying			Calculated
	amount			estimate			amount			estimate
	(in thousands)
Financial assets:
Cash and cash equivalents	$	982,305		$	982,305		$	933,755		$	933,755
Interest-bearing deposits at banks		100,101			100,101			101,222			101,222
Trading account assets		413,737			413,737			523,834			523,834
Investment securities		6,507,165			6,418,912			7,150,540			7,051,454
Loans and leases:
Commercial loans and leases		13,826,299			13,566,686			13,390,610			13,135,569
Commercial real estate loans		20,891,615			20,563,422			21,183,161			20,840,346
Residential real estate loans		6,154,960			5,876,173			5,928,056			5,699,028
Consumer loans		11,245,807			10,949,858			11,488,555			11,178,583
Allowance for credit losses		(903,703	)		—			(902,941	)		—

Loans and leases, net		51,214,978			50,956,139			51,087,441			50,853,526
Accrued interest receivable		220,922			220,922			202,182			202,182

Financial liabilities:
Noninterest-bearing deposits	$	(15,219,562	)	$	(15,219,562	)	$	(14,557,568	)	$	(14,557,568	)
Savings deposits and NOW accounts		(28,756,435	)		(28,756,435	)		(27,824,630	)		(27,824,630	)
Time deposits		(5,508,432	)		(5,548,229	)		(5,817,170	)		(5,865,779	)
Deposits at Cayman Islands office		(1,063,670	)		(1,063,670	)		(1,605,916	)		(1,605,916	)
Short-term borrowings		(504,676	)		(504,676	)		(947,432	)		(947,432	)
Long-term borrowings		(7,305,420	)		(7,442,997	)		(7,840,151	)		(7,937,397	)
Accrued interest payable		(95,762	)		(95,762	)		(71,954	)		(71,954	)
Trading account liabilities		(303,930	)		(303,930	)		(333,222	)		(333,222	)

Other financial instruments:
Commitments to originate real estate loans for sale	$	16,147		$	16,147		$	2,244		$	2,244
Commitments to sell real estate loans		(2,499	)		(2,499	)		12,178			12,178
Other credit-related commitments		(68,108	)		(68,108	)		(74,426	)		(74,426	)
Interest rate swap agreements used for interest rate risk management		84,232			84,232			96,637			96,637

Commitments and contingencies (Tables)

3 Months Ended

Mar. 31, 2011

Commitments and Contingencies (Tables) [Abstract]

Company's significant commitments


	March 31,		December 31,
	2011		2010
	(in thousands)
Commitments to extend credit Home equity lines of credit	$	6,274,649		6,281,366
Commercial real estate loans to be sold		422,511		72,930
Other commercial real estate and construction		1,779,514		1,672,006
Residential real estate loans to be sold		438,283		161,583
Other residential real estate		112,328		151,111
Commercial and other		8,816,887		8,332,199

Standby letters of credit		3,852,506		3,917,318

Commercial letters of credit		58,805		76,962

Financial guarantees and indemnification contracts		1,707,670		1,609,944

Commitments to sell real estate loans		889,631		734,696

Segment information (Tables)

3 Months Ended

Mar. 31, 2011

Segment information (Tables) [Abstract]

Information about the Company's segments


	Three months ended March 31
	2011								2010
			Inter-			Net						Inter-			Net
	Total		segment			income			Total			segment			income
	revenues(a)		revenues			(loss)			revenues(a)			revenues			(loss)
	(in thousands)
Business Banking	$	99,777		962			26,300			101,796			—			25,344
Commercial Banking		213,612		1,166			88,331			192,406			—			76,868
Commercial Real Estate		125,306		356			49,010			110,413			18			43,753
Discretionary Portfolio		42,483		(7,787	)		16,127			(12,233	)		(2,747	)		(16,162	)
Residential Mortgage Banking		57,848		10,307			4,785			63,117			8,197			595
Retail Banking		295,048		2,987			52,726			307,475			2,687			59,037
All Other		49,150		(7,991	)		(31,006	)		51,066			(8,155	)		(38,480	)

Total	$	883,224		—			206,273			814,040			—			150,955

Summary of segment information


	Average total assets
	Three months ended				Year ended
	March 31				December 31
	2011		2010		2010
	(in millions)
Business Banking	$	4,754		4,959		4,843
Commercial Banking		16,114		15,509		15,461
Commercial Real Estate		13,635		13,368		13,194
Discretionary Portfolio		13,931		14,571		14,690
Residential Mortgage Banking		2,045		2,222		2,217
Retail Banking		11,653		12,272		12,079
All Other		5,913		5,982		5,896

Total	$	68,045		68,883		68,380


(a)		Total revenues are comprised of net interest income and other income. Net interest income is the difference between taxable-equivalent interest earned on assets and interest paid on liabilities owed by a segment and a funding charge (credit) based on the Company’s internal funds transfer pricing and allocation methodology. Segments are charged a cost to fund any assets (e.g. loans) and are paid a funding credit for any funds provided (e.g. deposits). The taxable-equivalent adjustment aggregated $6,327,000 and $5,923,000 for the three-month periods ended March 31, 2011 and 2010, respectively, and is eliminated in “All Other” total revenues. Intersegment revenues are included in total revenues of the reportable segments. The elimination of intersegment revenues is included in the determination of “All Other” total revenues.

Acquisitions (Details) $ in Thousands	3 Months Ended
Acquisitions (Details) $ in Thousands	Mar. 31, 2011 USD ($)	Dec. 31, 2010 USD ($)	Mar. 31, 2010 USD ($)	Nov. 05, 2010 USD ($)	Nov. 01, 2010 USD ($) shares	Oct. 29, 2010 $ / shares	Dec. 31, 2009 USD ($)
Summary of merger-related expenses
Salaries and employee benefits	$ 266,090		$ 264,046
Equipment and net occupancy	56,663		55,401
Printing, postage and supplies	9,202		9,043
Other costs of operations	136,208		123,049
Total merger-related expenses	0
Acquisitions (Textuals) [Abstract]
Assets	67,881,208	$ 68,021,263
Loans and leases	52,435,574	52,315,942
Cash and cash equivalents	982,305	933,755	$ 1,043,669				$ 1,246,342
Liabilities	59,373,690	59,663,568
Deposits	50,548,099	49,805,284
Investment securities	6,507,165	7,150,540
Additional Acquisitions (Textuals) [Abstract]
Common stock price on October 29, 2010, used to value purchase price and exchange ratio \| $ / shares						74.75
After-tax gain on K Bank transaction		17,000
Pre-tax gain on K Bank transaction		28,000
Merger-related expenses	0
K Bank And Wilmington Trust Corporation Acquisition [Member]
Summary of merger-related expenses
Salaries and employee benefits	7
Equipment and net occupancy	79
Printing, postage and supplies	147
Other costs of operations	4,062
Total merger-related expenses	4,295
Additional Acquisitions (Textuals) [Abstract]
Merger-related expenses	$ 4,295
Wilmington Trust Corporation [Member]
Acquisitions (Textuals) [Abstract]
Assets		10,900,000
Loans and leases		7,500,000
Liabilities		10,100,000
Deposits		9,000,000
Assets under management		43,600,000
Affiliates of Wilmington Trust Corporation [Member]
Acquisitions (Textuals) [Abstract]
Assets under management		16,500,000
Wilmington Trust Corporation Pending Aquisition [Member]
Acquisitions (Textuals) [Abstract]
Shares of M&T common stock to be exchanged for each share of Wilmington Trust common stock \| shares					0.051372
Value of pending acquisition stock for stock transaction					$ 351,000
Preferred stock to be assumed as part of Wilmington Trust acquisition					$ 330,000
K Bank Acquisition [Member]
Acquisitions (Textuals) [Abstract]
Assets acquired total				$ 556,000
Loans and leases				154,000
Cash and cash equivalents				186,000
Liabilities				528,000
Deposits				$ 491,000
Wilmington Trust Corporation and Affiliates [Member]
Acquisitions (Textuals) [Abstract]
Assets under management		$ 60,100,000

Investment securities (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
Investment securities (Details) - USD ($) $ in Thousands	Mar. 31, 2011	Dec. 31, 2010
Investment securities available for sale:
Investment securities, available for sale, amortized cost	$ 4,932,460	$ 5,494,377
Gross Unrealized Gains	188,952	230,852
Gross Unrealized Losses	266,428	311,737
Estimated fair value	4,854,984	5,413,492
Investment securities held to maturity:
Amortized Cost for Held-to-maturity	1,262,089	1,324,339
Gross Unrealized Gains for Held-to-maturity	13,659	16,005
Gross Unrealized Losses for Held-to-maturity	101,912	115,091
Estimated fair value for Held-to-maturity	1,173,836	1,225,253
Amortized cost and estimated fair value of investment securities
Other securities, Amortized Cost	390,092	412,709
Other securities, Estimated fair value	390,092	412,709
Total for Amortized cost	6,584,641	7,231,425
Total for Gross Unrealized Gains	202,611	246,857
Total for Gross Unrealized losses	368,340	426,828
Total for Estimated fair value	6,418,912	7,051,454
Obligations of states and political subdivisions [Member]
Investment securities held to maturity:
Amortized Cost for Held-to-maturity	191,251	191,119
Gross Unrealized Gains for Held-to-maturity	1,916	1,944
Gross Unrealized Losses for Held-to-maturity	1,166	694
Estimated fair value for Held-to-maturity	192,001	192,369
Other Debt Securities [Member]
Investment securities held to maturity:
Amortized Cost for Held-to-maturity	12,447	12,575
Estimated fair value for Held-to-maturity	12,447	12,575
U.S. Treasury and federal agencies [Member]
Investment securities available for sale:
Investment securities, available for sale, amortized cost	38,531	61,772
Gross Unrealized Gains	758	1,680
Gross Unrealized Losses	150	18
Estimated fair value	39,139	63,434
Obligations of states and political subdivisions [Member]
Investment securities available for sale:
Investment securities, available for sale, amortized cost	59,010	59,921
Gross Unrealized Gains	442	561
Gross Unrealized Losses	62	57
Estimated fair value	59,390	60,425
Government issued or guaranteed [Member]
Investment securities available for sale:
Investment securities, available for sale, amortized cost	2,732,299	3,146,054
Gross Unrealized Gains	108,911	161,298
Gross Unrealized Losses	1,349	1,111
Estimated fair value	2,839,861	3,306,241
Privately issued [Member]
Investment securities available for sale:
Investment securities, available for sale, amortized cost	1,600,110	1,677,064
Gross Unrealized Gains	14,006	10,578
Gross Unrealized Losses	222,238	252,081
Estimated fair value	1,391,878	1,435,561
Privately issued commercial [Member]
Investment securities available for sale:
Investment securities, available for sale, amortized cost	23,232	25,357
Gross Unrealized Losses	2,765	2,950
Estimated fair value	20,467	22,407
Collateralized Debt Obligations [Member]
Investment securities available for sale:
Investment securities, available for sale, amortized cost	94,290	95,080
Gross Unrealized Gains	27,734	24,754
Gross Unrealized Losses	7,759	9,078
Estimated fair value	114,265	110,756
Other Debt Securities [Member]
Investment securities available for sale:
Investment securities, available for sale, amortized cost	306,870	310,017
Gross Unrealized Gains	29,980	26,883
Gross Unrealized Losses	30,301	38,000
Estimated fair value	306,549	298,900
Equity Securities [Member]
Investment securities available for sale:
Investment securities, available for sale, amortized cost	78,118	119,112
Gross Unrealized Gains	7,121	5,098
Gross Unrealized Losses	1,804	8,442
Estimated fair value	$ 83,435	$ 115,768

Investment Securities (Details 1) - USD ($) $ in Thousands	3 Months Ended
Investment Securities (Details 1) - USD ($) $ in Thousands	Mar. 31, 2011	Mar. 31, 2010
Changes in credit losses associated with debt securities for which other than temporary impairment losses
Estimated credit losses - beginning balance	$ 327,912	$ 284,513
Additions for credit losses not previously recognized	16,041	26,802
Reductions for increases in cash flows	(139)	(169)
Reductions for realized losses	(21,095)	(3,129)
Estimated credit losses - ending balance	$ 322,719	$ 308,017

Investment Securities (Details 2) $ in Thousands	Mar. 31, 2011 USD ($)
Debt securities available for sale:
Due in one year or less	$ 7,437
Due after one year through five years	64,615
Due after five years through ten years	19,518
Due after ten years	407,131
Available For Sale Securities Debt Maturities With Single Maturity Date Amortized Cost	498,701
Mortgage-backed securities available for sale	4,355,641
Total	4,854,342
Debt securities available for sale:
Due in one year or less	7,532
Due after one year through five years	65,828
Due after five years through ten years	21,162
Due after ten years	424,821
Available For Sale Securities Debt Maturities With Single Maturity Date Fair Value	519,343
Mortgage-backed securities available for sale	4,252,206
Total	4,771,549
Debt securities held to maturity:
Due in one year or less	28,334
Due after one year through five years	14,306
Due after five years through ten years	140,556
Due after ten years	20,502
Held To Maturity Securities Debt Maturities With Single Maturity Date Net Carrying Amount	203,698
Mortgage-backed securities held to maturity	1,058,391
Total	1,262,089
Debt securities held to maturity:
Due in one year or less	28,496
Due after one year through five years	14,719
Due after five years through ten years	140,782
Due after ten years	20,451
Held To Maturity Securities Debt Maturities With Single Maturity Date Fair Value	204,448
Mortgage-backed securities held to maturity	969,388
Total	$ 1,173,836

Investment Securities (Details 3) - USD ($) $ in Thousands	Mar. 31, 2011	Dec. 31, 2010
Investment Securities Continuous Unrealized Loss Position Fair Value [Abstract]
Estimated fair value, Less than 12 months	$ 126,208	$ 180,622
Unrealized Losses, Less than 12 months	(8,155)	(12,859)
Estimated fair value, 12 months or more	1,146,459	1,180,395
Unrealized Losses, 12 months or more	(258,273)	(298,878)
U.S. Treasury and federal agencies [Member]
Investment Securities Continuous Unrealized Loss Position Fair Value [Abstract]
Estimated fair value, Less than 12 months	23,884	27,289
Unrealized Losses, Less than 12 months	(150)	(18)
Estimated fair value, 12 months or more	0	0
Unrealized Losses, 12 months or more	0	0
Obligations of states and political subdivisions [Member]
Investment Securities Continuous Unrealized Loss Position Fair Value [Abstract]
Estimated fair value, Less than 12 months	3,488	3,712
Unrealized Losses, Less than 12 months	(26)	(18)
Estimated fair value, 12 months or more	2,062	2,062
Unrealized Losses, 12 months or more	(36)	(39)
Government issued or guaranteed [Member]
Investment Securities Continuous Unrealized Loss Position Fair Value [Abstract]
Estimated fair value, Less than 12 months	69,731	68,507
Unrealized Losses, Less than 12 months	(1,311)	(1,079)
Estimated fair value, 12 months or more	3,212	2,965
Unrealized Losses, 12 months or more	(38)	(32)
Privately issued residential [Member]
Investment Securities Continuous Unrealized Loss Position Fair Value [Abstract]
Estimated fair value, Less than 12 months	7,675	61,192
Unrealized Losses, Less than 12 months	(523)	(1,054)
Estimated fair value, 12 months or more	1,014,944	1,057,315
Unrealized Losses, 12 months or more	(221,715)	(251,027)
Privately issued commercial [Member]
Investment Securities Continuous Unrealized Loss Position Fair Value [Abstract]
Estimated fair value, Less than 12 months	0	0
Unrealized Losses, Less than 12 months	0	0
Estimated fair value, 12 months or more	20,467	22,407
Unrealized Losses, 12 months or more	(2,765)	(2,950)
Collateralized Debt Obligations [Member]
Investment Securities Continuous Unrealized Loss Position Fair Value [Abstract]
Estimated fair value, Less than 12 months	15,011	12,462
Unrealized Losses, Less than 12 months	(5,567)	(6,959)
Estimated fair value, 12 months or more	8,156	6,004
Unrealized Losses, 12 months or more	(2,192)	(2,119)
Other Debt Securities [Member]
Investment Securities Continuous Unrealized Loss Position Fair Value [Abstract]
Estimated fair value, Less than 12 months	3,767	2,134
Unrealized Losses, Less than 12 months	(68)	(10)
Estimated fair value, 12 months or more	96,364	88,969
Unrealized Losses, 12 months or more	(30,233)	(37,990)
Equity Securities [Member]
Investment Securities Continuous Unrealized Loss Position Fair Value [Abstract]
Estimated fair value, Less than 12 months	2,652	5,326
Unrealized Losses, Less than 12 months	(510)	(3,721)
Estimated fair value, 12 months or more	1,254	673
Unrealized Losses, 12 months or more	$ (1,294)	$ (4,721)

Investment Securities (Details 4) - USD ($) $ in Thousands	Mar. 31, 2011	Dec. 31, 2010
Held To Maturity Securities Continuous Unrealized Loss Position [Abstract]
Held to maturity, Estimated fair value, Less than 12 months	$ 86,929	$ 76,318
Held to maturity, Unrealized Losses, Less than 12 months	(1,128)	(638)
Held to maturity, Estimated fair value, 12 months or more	194,222	198,607
Held to maturity, Unrealized Losses, 12 months or more	(100,784)	(114,453)
Investment securities in continuous unrealized loss position
Investment Securities Continuous Unrealized Loss Position Less Than Twelve Months Aggregate Losses	213,137	256,940
Total of investment securities,unrealized losses, less than 12 months	(9,283)	(13,497)
Total of investment securities, fair value, more than 12 months	1,340,681	1,379,002
Total of investment securities,unrealized losses, more than 12 months	(359,057)	(413,331)
Obligations of states and political subdivisions [Member]
Held To Maturity Securities Continuous Unrealized Loss Position [Abstract]
Held to maturity, Estimated fair value, Less than 12 months	86,929	76,318
Held to maturity, Unrealized Losses, Less than 12 months	(1,128)	(638)
Held to maturity, Estimated fair value, 12 months or more	470	467
Held to maturity, Unrealized Losses, 12 months or more	(38)	(56)
Privately Issued Mortgage Backed Securities [Member]
Held To Maturity Securities Continuous Unrealized Loss Position [Abstract]
Held to maturity, Estimated fair value, Less than 12 months	0	0
Held to maturity, Unrealized Losses, Less than 12 months	0	0
Held to maturity, Estimated fair value, 12 months or more	193,752	198,140
Held to maturity, Unrealized Losses, 12 months or more	$ (100,746)	$ (114,397)

Investment Securities (Details Textuals) $ in Thousands	3 Months Ended		12 Months Ended
Investment Securities (Details Textuals) $ in Thousands	Mar. 31, 2011 USD ($)	Mar. 31, 2010 USD ($)	Dec. 31, 2010 USD ($)
Investment securities (Textuals) [Abstract]
Gross realized gains on investment securities	$ 39,400	$ 1,200
Gross realized losses on investment securities	36	777
Pre-tax other-than-temporary impairment losses	$ (16,041)	(26,802)
Number of investment securities with aggregate gross unrealized losses	562
Unrealized losses on individual investment securities	$ 368,340		$ 426,828
Unrealized losses on privately issued residential mortgage-backed securities	323,000
Residential mortgage-backed securities at cost	1,500,000
Unrealized losses on trust preferred securities issued by financial institutions and securities backed by trust preferred securities	38,000
Other debt securities at cost	161,000
Other debt securities fair value	390,092		$ 412,709
Mortgage-backed securities sold that were guaranteed by Fannie Mae and Freddie Mac [Member]
Investment securities (Textuals) [Abstract]
Aggregate amortized cost of The Federal National Mortgage Association and The Federal Home Loan Mortgage Corporation	484,000
Pre-tax gain on sale of mortgage-backed securities	39,000
Privately issued residential mortgage-backed securities [Member]
Investment securities (Textuals) [Abstract]
Pre-tax other-than-temporary impairment losses	$ 16,000	$ 27,000

Loans and Leases and the Allowance for Credit Losses (Details) $ in Thousands	Mar. 31, 2011 USD ($)
Outstanding principal and carrying value of acquired loans recorded at fair value
Outstanding principal balance	$ 3,509,711
Carrying amount	$ 3,184,469

Loans and leases and the allowance for credit losses (Details 1) - USD ($) $ in Thousands	Mar. 31, 2011	Dec. 31, 2010
Summary of current, past due and nonaccrual loans
Current	$ 50,008,710	$ 49,739,383
30-89 days past due	545,791	645,193
90 days or more past due and accruing	264,480	269,593
Purchased impaired	88,589	97,019
Nonaccrual	1,211,111	1,239,194
Total loans and leases, net of unearned discount	52,118,681	51,990,382
Commercial, financial, leasing [Member]
Summary of current, past due and nonaccrual loans
Current	13,605,508	13,088,887
30-89 days past due	24,626	96,087
90 days or more past due and accruing	21,055	16,647
Purchased impaired	1,922	2,250
Nonaccrual	173,188	186,739
Total loans and leases, net of unearned discount	13,826,299	13,390,610
Commercial Real Estate Excluding Residential Builder and Developer and Other Construction [Member]
Summary of current, past due and nonaccrual loans
Current	16,606,831	16,589,240
30-89 days past due	75,829	89,906
90 days or more past due and accruing	22,765	35,338
Purchased impaired	7,115	8,275
Nonaccrual	229,630	209,031
Total loans and leases, net of unearned discount	16,942,170	16,931,790
Residential builder and developer [Member]
Summary of current, past due and nonaccrual loans
Current	886,832	891,764
30-89 days past due	21,859	30,805
90 days or more past due and accruing	4,493	9,763
Purchased impaired	68,442	72,710
Nonaccrual	320,295	346,448
Total loans and leases, net of unearned discount	1,301,921	1,351,490
Other commercial construction [Member]
Summary of current, past due and nonaccrual loans
Current	2,421,823	2,723,399
30-89 days past due	97,824	36,420
90 days or more past due and accruing	17,327	11,323
Purchased impaired	2,013	2,098
Nonaccrual	108,537	126,641
Total loans and leases, net of unearned discount	2,647,524	2,899,881
Residential real estate excluding Alt-A [Member]
Summary of current, past due and nonaccrual loans
Current	4,983,032	4,699,711
30-89 days past due	194,594	229,641
90 days or more past due and accruing	195,241	192,276
Purchased impaired	6,897	9,320
Nonaccrual	178,109	172,729
Total loans and leases, net of unearned discount	5,557,873	5,303,677
Residential Alt-A [Member]
Summary of current, past due and nonaccrual loans
Current	450,829	475,236
30-89 days past due	35,469	42,674
90 days or more past due and accruing	0	0
Purchased impaired	0	0
Nonaccrual	110,789	106,469
Total loans and leases, net of unearned discount	597,087	624,379
Home equity lines and loans [Member]
Summary of current, past due and nonaccrual loans
Current	6,340,612	6,472,563
30-89 days past due	34,338	38,367
90 days or more past due and accruing	0	0
Purchased impaired	2,200	2,366
Nonaccrual	44,350	43,055
Total loans and leases, net of unearned discount	6,421,500	6,556,351
Automobile [Member]
Summary of current, past due and nonaccrual loans
Current	2,545,546	2,608,230
30-89 days past due	33,784	44,604
90 days or more past due and accruing	0	0
Purchased impaired	0	0
Nonaccrual	29,839	31,892
Total loans and leases, net of unearned discount	2,609,169	2,684,726
Other [Member]
Summary of current, past due and nonaccrual loans
Current	2,167,697	2,190,353
30-89 days past due	27,468	36,689
90 days or more past due and accruing	3,599	4,246
Purchased impaired	0	0
Nonaccrual	16,374	16,190
Total loans and leases, net of unearned discount	2,215,138	2,247,478
Purchased Impaired [Member]
Summary of current, past due and nonaccrual loans
Total loans and leases, net of unearned discount	88,589	97,019
Purchased Impaired [Member] \| Commercial, financial, leasing [Member]
Summary of current, past due and nonaccrual loans
Total loans and leases, net of unearned discount	$ 1,922	$ 2,250

Loans and leases and the allowance for credit losses (Details 2) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2011	Mar. 31, 2010
Allowance for credit losses
Beginning balance	$ 902,941	$ 878,022
Provision for credit losses	75,000	105,000
Consolidation of loan securitization trusts		2,752
Net charge-offs
Charge-offs	(83,094)	(106,039)
Recoveries	8,856	11,530
Net charge-offs	(74,238)	(94,509)
Ending balance	903,703	$ 891,265
Commercial, financial, leasing [Member]
Allowance for credit losses
Beginning balance	212,579
Provision for credit losses	14,942
Net charge-offs
Charge-offs	(14,027)
Recoveries	2,165
Net charge-offs	(11,862)
Ending balance	215,659
Commercial real estate loans [Member]
Allowance for credit losses
Beginning balance	400,562
Provision for credit losses	14,775
Net charge-offs
Charge-offs	(24,579)
Recoveries	349
Net charge-offs	(24,230)
Ending balance	391,107
Residential real estate loans [Member]
Allowance for credit losses
Beginning balance	86,351
Provision for credit losses	15,841
Net charge-offs
Charge-offs	(16,167)
Recoveries	1,501
Net charge-offs	(14,666)
Ending balance	87,526
Consumer loans [Member]
Allowance for credit losses
Beginning balance	133,067
Provision for credit losses	27,764
Net charge-offs
Charge-offs	(28,321)
Recoveries	4,841
Net charge-offs	(23,480)
Ending balance	137,351
Unallocated [Member]
Allowance for credit losses
Beginning balance	70,382
Provision for credit losses	1,678
Net charge-offs
Ending balance	$ 72,060

Loans and leases and the allowance for credit losses (Details 3) - USD ($) $ in Thousands	Mar. 31, 2011	Dec. 31, 2010
Impaired loans and leases
Recorded Investment, with an allowance recorded	$ 900,976	$ 904,504
Unpaid Principal Balance, with an allowance recorded	1,092,532	1,043,304
Related Allowance, with an allowance recorded	193,337	213,933
Recorded investment, with no related allowance recorded	340,123	349,223
Unpaid Principal Balance, with no related allowance recorded	452,436	433,129
Recorded Investment, Total	1,241,099	1,253,727
Unpaid Principal Balance, Total	1,544,968	1,476,433
Related Allowance, Total	193,337	213,933
Commercial, financial, leasing [Member]
Impaired loans and leases
Recorded Investment, with an allowance recorded	102,977	121,744
Unpaid Principal Balance, with an allowance recorded	153,773	170,888
Related Allowance, with an allowance recorded	33,363	40,909
Recorded investment, with no related allowance recorded	70,829	65,827
Unpaid Principal Balance, with no related allowance recorded	92,904	86,332
Recorded Investment, Total	173,806	187,571
Unpaid Principal Balance, Total	246,677	257,220
Related Allowance, Total	33,363	40,909
Commercial Real Estate Excluding Residential Builder and Developer and Other Construction [Member]
Impaired loans and leases
Recorded Investment, with an allowance recorded	131,923	110,975
Unpaid Principal Balance, with an allowance recorded	162,211	140,015
Related Allowance, with an allowance recorded	26,629	17,393
Recorded investment, with no related allowance recorded	101,076	101,939
Unpaid Principal Balance, with no related allowance recorded	120,472	116,316
Recorded Investment, Total	232,999	212,914
Unpaid Principal Balance, Total	282,683	256,331
Related Allowance, Total	26,629	17,393
Residential builder and developer [Member]
Impaired loans and leases
Recorded Investment, with an allowance recorded	250,433	263,545
Unpaid Principal Balance, with an allowance recorded	304,636	295,031
Related Allowance, with an allowance recorded	65,578	78,597
Recorded investment, with no related allowance recorded	108,764	100,799
Unpaid Principal Balance, with no related allowance recorded	150,480	124,383
Recorded Investment, Total	359,197	364,344
Unpaid Principal Balance, Total	455,116	419,414
Related Allowance, Total	65,578	78,597
Other commercial construction [Member]
Impaired loans and leases
Recorded Investment, with an allowance recorded	84,617	80,934
Unpaid Principal Balance, with an allowance recorded	110,488	85,432
Related Allowance, with an allowance recorded	12,839	22,067
Recorded investment, with no related allowance recorded	25,893	46,656
Unpaid Principal Balance, with no related allowance recorded	31,865	50,496
Recorded Investment, Total	110,510	127,590
Unpaid Principal Balance, Total	142,353	135,928
Related Allowance, Total	12,839	22,067
Residential real estate excluding Alt-A [Member]
Impaired loans and leases
Recorded Investment, with an allowance recorded	83,405	73,006
Unpaid Principal Balance, with an allowance recorded	101,223	85,279
Related Allowance, with an allowance recorded	3,945	3,375
Recorded investment, with no related allowance recorded	4,276	5,035
Unpaid Principal Balance, with no related allowance recorded	6,443	7,723
Recorded Investment, Total	87,681	78,041
Unpaid Principal Balance, Total	107,666	93,002
Related Allowance, Total	3,945	3,375
Residential Alt-A [Member]
Impaired loans and leases
Recorded Investment, with an allowance recorded	173,091	180,665
Unpaid Principal Balance, with an allowance recorded	184,022	191,445
Related Allowance, with an allowance recorded	35,000	36,000
Recorded investment, with no related allowance recorded	29,285	28,967
Unpaid Principal Balance, with no related allowance recorded	50,272	47,879
Recorded Investment, Total	202,376	209,632
Unpaid Principal Balance, Total	234,294	239,324
Related Allowance, Total	35,000	36,000
Home equity lines and loans [Member]
Impaired loans and leases
Recorded Investment, with an allowance recorded	11,895	11,799
Unpaid Principal Balance, with an allowance recorded	13,544	13,378
Related Allowance, with an allowance recorded	2,423	2,227
Recorded Investment, Total	11,895	11,799
Unpaid Principal Balance, Total	13,544	13,378
Related Allowance, Total	2,423	2,227
Automobile [Member]
Impaired loans and leases
Recorded Investment, with an allowance recorded	59,465	58,858
Unpaid Principal Balance, with an allowance recorded	59,465	58,858
Related Allowance, with an allowance recorded	12,774	12,597
Recorded Investment, Total	59,465	58,858
Unpaid Principal Balance, Total	59,465	58,858
Related Allowance, Total	12,774	12,597
Other [Member]
Impaired loans and leases
Recorded Investment, with an allowance recorded	3,170	2,978
Unpaid Principal Balance, with an allowance recorded	3,170	2,978
Related Allowance, with an allowance recorded	786	768
Recorded Investment, Total	3,170	2,978
Unpaid Principal Balance, Total	3,170	2,978
Related Allowance, Total	$ 786	$ 768

Loans and leases and the allowance for credit losses (Details 4) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2011	Mar. 31, 2010
Interest income recognized on loans
Average Recorded Investment	$ 1,257,459	$ 1,336,833
Interest Income Recognized, Total	6,659	5,088
Interest Income Recognized, Cash Basis	3,269	2,443
Commercial, financial, leasing [Member]
Interest income recognized on loans
Average Recorded Investment	184,546	331,564
Interest Income Recognized, Total	1,007	455
Interest Income Recognized, Cash Basis	1,001	455
Commercial Real Estate Excluding Residential Builder and Developer and Other Construction [Member]
Interest income recognized on loans
Average Recorded Investment	221,601	289,470
Interest Income Recognized, Total	384	371
Interest Income Recognized, Cash Basis	342	371
Residential builder and developer [Member]
Interest income recognized on loans
Average Recorded Investment	362,129	321,822
Interest Income Recognized, Total	527	44
Interest Income Recognized, Cash Basis	130	44
Other commercial construction [Member]
Interest income recognized on loans
Average Recorded Investment	126,054	55,297
Interest Income Recognized, Total	510	384
Interest Income Recognized, Cash Basis	321	384
Residential real estate excluding Alt-A [Member]
Interest income recognized on loans
Average Recorded Investment	83,527	45,822
Interest Income Recognized, Total	1,034	532
Interest Income Recognized, Cash Basis	596	349
Residential Alt-A [Member]
Interest income recognized on loans
Average Recorded Investment	205,632	226,878
Interest Income Recognized, Total	1,995	2,183
Interest Income Recognized, Cash Basis	551	438
Home equity lines and loans [Member]
Interest income recognized on loans
Average Recorded Investment	12,076	12,491
Interest Income Recognized, Total	161	192
Interest Income Recognized, Cash Basis	26	38
Automobile [Member]
Interest income recognized on loans
Average Recorded Investment	58,863	50,253
Interest Income Recognized, Total	984	861
Interest Income Recognized, Cash Basis	296	348
Other [Member]
Interest income recognized on loans
Average Recorded Investment	3,031	3,236
Interest Income Recognized, Total	57	66
Interest Income Recognized, Cash Basis	$ 6	$ 16

Loans and leases and the allowance for credit losses (Details 5) - USD ($) $ in Thousands	Mar. 31, 2011	Dec. 31, 2010
Summary of Loan grades
Loans and leases, net of unearned discount	$ 52,118,681	$ 51,990,382
Commercial, financial, leasing [Member]
Summary of Loan grades
Loans and leases, net of unearned discount	13,826,299	13,390,610
Commercial real estate loans [Member]
Summary of Loan grades
Loans and leases, net of unearned discount	20,891,615	21,183,161
Commercial Real Estate Excluding Residential Builder and Developer and Other Construction [Member]
Summary of Loan grades
Loans and leases, net of unearned discount	16,942,170	16,931,790
Residential builder and developer [Member]
Summary of Loan grades
Loans and leases, net of unearned discount	1,301,921	1,351,490
Other commercial construction [Member]
Summary of Loan grades
Loans and leases, net of unearned discount	2,647,524	2,899,881
Pass [Member] \| Commercial, financial, leasing [Member]
Summary of Loan grades
Loans and leases, net of unearned discount	12,909,951	12,371,138
Pass [Member] \| Commercial Real Estate Excluding Residential Builder and Developer and Other Construction [Member]
Summary of Loan grades
Loans and leases, net of unearned discount	15,752,006	15,831,104
Pass [Member] \| Residential builder and developer [Member]
Summary of Loan grades
Loans and leases, net of unearned discount	676,164	693,110
Pass [Member] \| Other commercial construction [Member]
Summary of Loan grades
Loans and leases, net of unearned discount	2,090,831	2,253,589
Criticized Accrual [Member] \| Commercial, financial, leasing [Member]
Summary of Loan grades
Loans and leases, net of unearned discount	743,160	832,733
Criticized Accrual [Member] \| Commercial Real Estate Excluding Residential Builder and Developer and Other Construction [Member]
Summary of Loan grades
Loans and leases, net of unearned discount	960,534	891,655
Criticized Accrual [Member] \| Residential builder and developer [Member]
Summary of Loan grades
Loans and leases, net of unearned discount	305,462	311,932
Criticized Accrual [Member] \| Other commercial construction [Member]
Summary of Loan grades
Loans and leases, net of unearned discount	448,156	519,651
Criticized Nonaccrual [Member] \| Commercial, financial, leasing [Member]
Summary of Loan grades
Loans and leases, net of unearned discount	173,188	186,739
Criticized Nonaccrual [Member] \| Commercial Real Estate Excluding Residential Builder and Developer and Other Construction [Member]
Summary of Loan grades
Loans and leases, net of unearned discount	229,630	209,031
Criticized Nonaccrual [Member] \| Residential builder and developer [Member]
Summary of Loan grades
Loans and leases, net of unearned discount	320,295	346,448
Criticized Nonaccrual [Member] \| Other commercial construction [Member]
Summary of Loan grades
Loans and leases, net of unearned discount	$ 108,537	$ 126,641

Loans and leases and the allowance for credit losses (Details 6) - USD ($) $ in Thousands	Mar. 31, 2011	Dec. 31, 2010	Mar. 31, 2010	Dec. 31, 2009
Allowance for credit losses on the basis of the Company's impairment methodology
Allowance for credit losses	$ 903,703	$ 902,941	$ 891,265	$ 878,022
Commercial, financial, leasing [Member]
Allowance for credit losses on the basis of the Company's impairment methodology
Allowance for credit losses	215,659	212,579
Commercial real estate loans [Member]
Allowance for credit losses on the basis of the Company's impairment methodology
Allowance for credit losses	391,107	400,562
Residential real estate loans [Member]
Allowance for credit losses on the basis of the Company's impairment methodology
Allowance for credit losses	87,526	86,351
Consumer loans [Member]
Allowance for credit losses on the basis of the Company's impairment methodology
Allowance for credit losses	137,351	133,067
Unallocated [Member]
Allowance for credit losses on the basis of the Company's impairment methodology
Allowance for credit losses	72,060	70,382
Allocated [Member]
Allowance for credit losses on the basis of the Company's impairment methodology
Allowance for credit losses	831,643	832,559
Individually evaluated for impairment [Member]
Allowance for credit losses on the basis of the Company's impairment methodology
Allowance for credit losses	188,890	209,033
Individually evaluated for impairment [Member] \| Commercial, financial, leasing [Member]
Allowance for credit losses on the basis of the Company's impairment methodology
Allowance for credit losses	33,211	40,459
Individually evaluated for impairment [Member] \| Commercial real estate loans [Member]
Allowance for credit losses on the basis of the Company's impairment methodology
Allowance for credit losses	101,993	114,082
Individually evaluated for impairment [Member] \| Residential real estate loans [Member]
Allowance for credit losses on the basis of the Company's impairment methodology
Allowance for credit losses	38,000	39,000
Individually evaluated for impairment [Member] \| Consumer loans [Member]
Allowance for credit losses on the basis of the Company's impairment methodology
Allowance for credit losses	15,686	15,492
Collectively evaluated for impairment [Member]
Allowance for credit losses on the basis of the Company's impairment methodology
Allowance for credit losses	638,306	618,626
Collectively evaluated for impairment [Member] \| Commercial, financial, leasing [Member]
Allowance for credit losses on the basis of the Company's impairment methodology
Allowance for credit losses	182,296	171,670
Collectively evaluated for impairment [Member] \| Commercial real estate loans [Member]
Allowance for credit losses on the basis of the Company's impairment methodology
Allowance for credit losses	286,061	282,505
Collectively evaluated for impairment [Member] \| Residential real estate loans [Member]
Allowance for credit losses on the basis of the Company's impairment methodology
Allowance for credit losses	48,581	46,976
Collectively evaluated for impairment [Member] \| Consumer loans [Member]
Allowance for credit losses on the basis of the Company's impairment methodology
Allowance for credit losses	121,368	117,475
Purchased Impaired [Member]
Allowance for credit losses on the basis of the Company's impairment methodology
Allowance for credit losses	4,447	4,900
Purchased Impaired [Member] \| Commercial, financial, leasing [Member]
Allowance for credit losses on the basis of the Company's impairment methodology
Allowance for credit losses	152	450
Purchased Impaired [Member] \| Commercial real estate loans [Member]
Allowance for credit losses on the basis of the Company's impairment methodology
Allowance for credit losses	3,053	3,975
Purchased Impaired [Member] \| Residential real estate loans [Member]
Allowance for credit losses on the basis of the Company's impairment methodology
Allowance for credit losses	945	375
Purchased Impaired [Member] \| Consumer loans [Member]
Allowance for credit losses on the basis of the Company's impairment methodology
Allowance for credit losses	$ 297	$ 100

Loans and leases and the allowance for credit losses (Details) (Textuals) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2011	Mar. 31, 2010
Loans and leases and allowance for credit losses (Details) (Textuals) [Abstract]
Interest income on loans acquired	$ 41	$ 43
Delinquency period for loan-by-loan evaluation of collectability on residential real estate loans and home equity loans and lines of credit	more than 150 days

Borrowings (Details) $ in Millions	3 Months Ended	12 Months Ended
Borrowings (Details) $ in Millions	Mar. 31, 2011 USD ($)	Dec. 31, 2010
Borrowings (Textuals) [Abstract]
Junior subordinated debentures	$ 1,200
Rate on related enhanced trust preferred securities	8.50%
Junior Subordinated Debentures Maturity Date	Jan. 31, 2068
Debt Maturity, Start Date	2027
Debt Maturity, End Date	2068
Period of days prior to redemption or repurchase of enhanced trust preferred securities applicable to provisions of the replacement capital covenant		180
End date of restrictions included in the replacement capital covenant	Jan. 31, 2048
Junior Subordinated Debenture due January 31, 2068 [Member]
Borrowings (Textuals) [Abstract]
Junior subordinated debentures	$ 350

Shareholders Equity (Details) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2011 USD ($) $ / shares shares	Apr. 01, 2011 shares	Dec. 31, 2010 USD ($) $ / shares shares
Issued and outstanding preferred stock
Preferred stock, shares issued	778,000		778,000
Preferred stock, shares outstanding	778,000		778,000
Carrying value \| $	$ 743,385		$ 740,657
Shareholders Equity (Textuals) [Abstract]
Preferred stock, shares authorized	1,000,000		1,000,000
Preferred stock, par value \| $ / shares	$ 1.00		$ 1.00
Liquidation preference \| $ / shares	$ 1,000		$ 1,000
Limitation by U.S. Treasury on maximum amount of dividend to be paid per common stock quarterly	0.70 per share
Preferred stock of Wilmington Trust Corporation to be redeemed at merger closing \| $	$ 330,000
M&T preferred stock to be repaid by the end of the second quarter of 2011 \| $	370,000
Perpetual preferred stock to be to be issued by the end of the second quarter of 2011 \| $	$ 500,000
Series A Fixed Rate Cumulative Perpetual Preferred Stock [Member]
Issued and outstanding preferred stock
Preferred stock, shares issued	600,000
Preferred stock, shares outstanding	600,000
Carrying value \| $	$ 580,203		$ 578,630
Shareholders Equity (Textuals) [Abstract]
Preferred stock, shares authorized	600,000
Liquidation preference \| $ / shares	$ 1,000
Series B Mandatory Convertible Non-cumulative Preferred Stock [Member]
Issued and outstanding preferred stock
Preferred stock, shares issued	26,500
Preferred stock, shares outstanding	26,500
Carrying value \| $	$ 26,500		26,500
Shareholders Equity (Textuals) [Abstract]
Preferred stock, shares authorized	26,500
Liquidation preference \| $ / shares	$ 1,000
Series C Fixed Rate Cumulative Perpetual Preferred Stock [Member]
Issued and outstanding preferred stock
Preferred stock, shares issued	151,500
Preferred stock, shares outstanding	151,500
Carrying value \| $	$ 136,682		$ 135,527
Shareholders Equity (Textuals) [Abstract]
Preferred stock, shares authorized	151,500
Liquidation preference \| $ / shares	$ 1,000
Ten Year Warrant Series A Preferred [Member]
Shareholders Equity (Textuals) [Abstract]
Ten-year warrant to purchase common stock	1,218,522
Ten Year Warrant Series C Preferred [Member]
Shareholders Equity (Textuals) [Abstract]
Ten-year warrant to purchase common stock	407,542
Series A [Member]
Shareholders Equity (Textuals) [Abstract]
Exercise price of each class of warrants or rights outstanding \| $ / shares	73.86
Series B [Member]
Shareholders Equity (Textuals) [Abstract]
Preferred stock dividend rate	10% per year
Number of common shares Series B preferred stock were converted into		433,144
Series C [Member]
Shareholders Equity (Textuals) [Abstract]
Exercise price of each class of warrants or rights outstanding \| $ / shares	55.76
Preferred series A and C first five years [Member]
Shareholders Equity (Textuals) [Abstract]
Preferred stock dividend rate	5% per year
Preferred series A and C after five years [Member]
Shareholders Equity (Textuals) [Abstract]
Preferred stock dividend rate	9% per year

Pension plans and other postretirement benefits (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2011	Mar. 31, 2010
Pension benefits [Member]
Net periodic defined benefit cost for defined benefit plans
Service cost	$ 5,300	$ 4,875
Interest cost on projected benefit obligation	12,150	12,029
Expected return on plan assets	(12,700)	(12,788)
Amortization of prior service cost	(1,650)	(1,650)
Amortization of net actuarial loss	5,100	3,321
Net periodic benefit costs	8,200	5,787
Other postretirement benefits [Member]
Net periodic defined benefit cost for defined benefit plans
Service cost	125	100
Interest cost on projected benefit obligation	775	780
Amortization of prior service cost	25	25
Net periodic benefit costs	$ 925	$ 905

Pension Plans and Other Postretirement Benefits (Details Textuals) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2011	Mar. 31, 2010
Additional pension plans and other postretirement benefits (Textual) [Abstract]
Defined contribution pension and retirement savings plans total expense	$ 10,176,000	$ 11,690,000

Earnings per common share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2011	Mar. 31, 2010
Net income available to common shareholders
Net income	$ 206,273	$ 150,955
Less: Preferred stock dividends	(10,498)	(10,056)
Amortization of preferred stock discount	(2,753)	(2,558)
Net income available to common equity	193,022	138,341
Less : Income attributable to unvested stock-based compensation awards	(2,909)	(1,913)
Net income available to common shareholders	$ 190,113	$ 136,428
Weighted-average shares outstanding:
Common shares outstanding (including common stock issuable) and unvested stock-based compensation awards	120,992	119,324
Less: Unvested stock-based compensation awards	(1,791)	(1,559)
Weighted-average shares outstanding	119,201	117,765
Basic earnings per common share	$ 1.59	$ 1.16
Computations of diluted earnings per common share
Net income available to common equity	$ 193,022	$ 138,341
Less : Income attributable to unvested stock-based compensation awards	(2,901)	(1,910)
Net income available to common shareholders	$ 190,121	$ 136,431
Adjusted weighted-average shares outstanding:
Common and unvested stock-based compensation	120,992	119,324
Less: Unvested stock-based compensation awards	(1,791)	(1,559)
Plus: Incremental shares from assumed conversion of stock-based compensation awards and convertible preferred stock	651	491
Adjusted weighted-average shares outstanding	119,852	118,256
Diluted earnings per common share	$ 1.59	$ 1.15
Earnings per common share (Textuals) [Abstract]
Antidilutive securities excluded from computation of earnings per share	10,500	11,900

Comprehensive income (Details) - USD ($) $ in Thousands	3 Months Ended
Comprehensive income (Details) - USD ($) $ in Thousands	Mar. 31, 2011	Mar. 31, 2010
Available for sale ("AFS") investment securities with other-than-temporary impairment ("OTTI"):
Unrealized holding gains, net, before-tax amount	$ 7,930	$ (29,487)
Unrealized holding gains, net, income taxes	(3,108)	11,574
Unrealized holding gains, net, net of tax amount	4,822	(17,913)
Less: OTTI charges recognized in net income AFS	(7,541)	(26,802)
Less: OTTI charges recognized in net income, income taxes	2,949	10,483
Less: OTTI charges recognized in net income, net	(4,592)	(16,319)
Net change for AFS investment securities with OTTI, before tax	15,471	(2,685)
Net change for AFS investment securities with OTTI, after tax	9,414	(1,594)
Net change for AFS investment securities with OTTI, income taxes	(6,057)	1,091
AFS investment securities - all other:
Unrealized holding gains, net, before-tax amount	31,577	131,379
Unrealized holding gains, net, income taxes	(12,372)	(51,456)
Unrealized holding gains, net, net of tax amount	19,205	79,923
Less: reclassification adjustment for gains/losses realized in net income, before-tax amount	39,353	(145)
Less: reclassification adjustment for gains/losses realized in net income, income taxes	(15,413)	44
Less: reclassification adjustment for gains/losses realized in net income, net	23,940	(101)
Net change for AFS investment securities - all other, before tax	(7,776)	131,524
Net change for AFS investment securities - all other, tax	3,041	(51,500)
Net change for AFS investment securities - all other, after tax	(4,735)	80,024
Unrealized holding gains on HTM securities, net, before-tax amount	(8,355)
Unrealized holding gains on HTM securities, net, income taxes	3,279
Unrealized holding gains on HTM securities, net, net of tax amount	(5,076)
Less: reclassification to income of unrealized holding losses before tax	230
Less: reclassification to income of unrealized holding losses tax	(90)
Less: reclassification to income of unrealized holding losses after tax	140
Less: OTTI charges recognized in net income, tax	3,336
Less: OTTI charges recognized in net income, before tax	(8,500)
Less: OTTI charges recognized in net income, after tax	(5,164)
Net change for investment securities with OTTI, before tax	(85)
Net change for investment securities with OTTI, tax	33
Net change for investment securities with OTTI, after tax	(52)
Reclassification to income of unrealized holding losses on securities previously transferred from AFS to HTM	1,698	2,347
Reclassification to income of unrealized holding losses on securities previously transferred from AFS to HTM, net of tax	1,031	1,426
Reclassification to income of unrealized holding losses on securities previously transferred from AFS to HTM, tax	(667)	(921)
Net unrealized gains/losses on investment securities, before-tax amount	9,308	131,186
Net unrealized gains/losses on investment securities, income taxes	(3,650)	(51,330)
Unrealized gains on investment securities	5,658	79,856
Reclassification to income for amortization of losses on terminated cash flow hedges to income, before-tax amount	(112)	(112)
Reclassification to income for amortization of losses on terminated cash flow hedges to income, income taxes	42	42
Reclassification to income for amortization of losses on terminated cash flow hedges to income, net	(70)	(70)
Defined benefit plans liability adjustment, before-tax amount	3,475	1,696
Defined benefit plans liability adjustment, income taxes	(1,364)	(666)
Defined benefit plans liability adjustment, net	2,111	1,030
Total Comprehensive Income, before-tax amount	12,671	132,770
Total Comprehensive Income, income taxes	(4,972)	(51,954)
Total Comprehensive Income, net	7,699	80,816
Accumulated other comprehensive income (loss), net consisted of unrealized gains (losses)
Beginning Balance	(205,220)	(335,997)
Net gain (loss) during period	7,699	80,816
Ending Balance	(197,521)	(255,181)
Cash flow hedges [Member]
AFS investment securities - all other:
Total Comprehensive Income, net	(70)	(70)
Accumulated other comprehensive income (loss), net consisted of unrealized gains (losses)
Beginning Balance	393	674
Net gain (loss) during period	(70)	(70)
Ending Balance	323	604
Defined benefit plans [Member]
AFS investment securities - all other:
Total Comprehensive Income, net	2,111	1,030
Accumulated other comprehensive income (loss), net consisted of unrealized gains (losses)
Beginning Balance	(120,892)	(117,046)
Net gain (loss) during period	2,111	1,030
Ending Balance	(118,781)	(116,016)
With OTTI [Member]
AFS investment securities - all other:
Total Comprehensive Income, net	9,362	(1,594)
Accumulated other comprehensive income (loss), net consisted of unrealized gains (losses)
Beginning Balance	(87,053)	(76,772)
Net gain (loss) during period	9,362	(1,594)
Ending Balance	(77,691)	(78,366)
All other [Member]
AFS investment securities - all other:
Total Comprehensive Income, net	(3,704)	81,450
Accumulated other comprehensive income (loss), net consisted of unrealized gains (losses)
Beginning Balance	2,332	(142,853)
Net gain (loss) during period	(3,704)	81,450
Ending Balance	$ (1,372)	$ (61,403)

Derivative financial instruments (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2011	Mar. 31, 2010	Dec. 31, 2010
Derivative financial instruments (Textuals) [Abstract]
Notional value of foreign currency and other option and future contracts entered into trading purposes	$ 982,000		$ 769,000
Information about fair values of derivative instruments in consolidated balance sheet
Derivative asset designated as hedging instrument, fair value	84,445		101,517
Derivative asset not designated as hedging instrument, fair value	345,180		370,048
Derivative liability not designated as hedging instrument, fair value	307,185		335,767
Derivative liability designated as hedging instrument, fair value	858		1,062
Total derivative asset, fair value	429,625		471,565
Total derivative liability, fair value	308,043		336,829
Information about fair values of derivative instruments in consolidated statement of income
Derivatives in fair value hedging relationships, derivatives	(12,405)	$ 12,271
Derivatives in fair value hedging relationships, hedged item	12,048	(11,782)
Derivatives not designated as hedging instruments, derivatives	(73)	(272)
Additonal Derivative financial instruments (Textuals) [Abstract]
Net unrealized pre-tax gains related to hedged loans held for sale, commitments to originate loans for sale and commitments to sell loans	19,000		17,000
Aggregate fair value of derivative financial instruments in a net liability position	174,000
Fair value of collateral posted for derivative financial instruments	159,000
Interest rate swap counterparty collateral postings	60,000
Fixed rate long-term borrowings [Member]
Information about interest rate swap agreements
Notional amount	$ 900,000		$ 900,000
Average maturity (in years)	6.1		6.4
Weighted-average rate, fixed	6.07%		6.07%
Weighted-average rate, variable	1.85%		1.84%
Fixed rate time deposits [Member]
Information about fair values of derivative instruments in consolidated statement of income
Derivatives in fair value hedging relationships, derivatives	$ 0	(199)
Derivatives in fair value hedging relationships, hedged item	0	199
Fixed rate long-term borrowings [Member]
Information about fair values of derivative instruments in consolidated statement of income
Derivatives in fair value hedging relationships, derivatives	(12,405)	12,470
Derivatives in fair value hedging relationships, hedged item	12,048	(11,981)
Interest rate swap agreements [Member]
Information about fair values of derivative instruments in consolidated balance sheet
Derivative asset designated as hedging instrument, fair value	84,232		$ 96,637
Derivative liability designated as hedging instrument, fair value	0		0
Interest rate contracts [Member]
Information about fair values of derivative instruments in consolidated balance sheet
Derivative asset not designated as hedging instrument, fair value	306,305		345,632
Derivative liability not designated as hedging instrument, fair value	282,387		321,461
Foreign exchange and other option and futures contracts [Member]
Information about fair values of derivative instruments in consolidated balance sheet
Derivative asset not designated as hedging instrument, fair value	21,327		11,267
Derivative liability not designated as hedging instrument, fair value	21,543		11,761
Commitments to sell real estate loans [Member]
Information about fair values of derivative instruments in consolidated balance sheet
Derivative asset designated as hedging instrument, fair value	213		4,880
Derivative asset not designated as hedging instrument, fair value	1,281		10,322
Derivative liability not designated as hedging instrument, fair value	3,135		1,962
Derivative liability designated as hedging instrument, fair value	858		1,062
Mortgage-related commitments to originate real estate loans for sale [Member]
Information about fair values of derivative instruments in consolidated balance sheet
Derivative asset not designated as hedging instrument, fair value	16,267		2,827
Derivative liability not designated as hedging instrument, fair value	120		583
Interest rate swap agreements [Member]
Derivative financial instruments (Textuals) [Abstract]
Increase in net interest income due to Interest Rate Swap agreements	10,000	$ 11,000
Interest rate contracts [Member]
Derivative financial instruments (Textuals) [Abstract]
Notional value of interest rate contracts entered into trading purposes	$ 12,300,000		$ 12,800,000

Variable interest entities and asset securitizations (Details) - USD ($) $ in Millions	Mar. 31, 2011	Dec. 31, 2010
Variable interest entities and asset securitizations (Textuals) [Abstract]
Carrying value of loans in the securitization trusts	$ 236	$ 265
Combined outstanding principal amount of mortgage backed securities issued by qualified special purpose trusts held by unrelated parties	37	40
Other assets for its "investment" in the common securities recognized by the company of various trusts	34
Total assets of real estate partnerships in which the company invested	1,200	1,100
Maximum exposure to loss of investments in real estate partnerships	249	258
Unfunded commitments included in company's maximum exposure to loss of investments in real estate partnerships	$ 71	$ 81

Fair value measurements (Details) $ in Thousands	3 Months Ended
Fair value measurements (Details) $ in Thousands	Mar. 31, 2011 USD ($)	Mar. 31, 2010 USD ($)	Dec. 31, 2010 USD ($)	Dec. 31, 2009 USD ($)
Assets measured at estimated fair value on a recurring basis [Line Items]
Trading account assets	$ 413,737		$ 523,834
Investment securities	4,854,984		5,413,492
Real estate loans held for sale	188,573		544,567
Other assets	101,993		114,666
Total assets	5,559,287		6,596,559
Liabilities measured at estimated fair value on a recurring basis [Line Items]
Trading account liabilities	303,930		333,222
Other liabilities	4,113		3,607
Total liabilities	308,043		336,829
Changes in Level 3 assets and liabilities measured at estimated fair value on a recurring basis
Beginning Balance	1,568,724	$ 2,205,836
Included in earnings	(7,541)	(26,802)
Included in other comprehensive income	64,837	87,457
Purchases, sales, issuances and settlements	(99,410)	(95,567)
Transfer in and/or out of Level 3		(355,248)
Ending Balance	1,526,610	1,815,676
Changes in unrealized gains (losses) included in earnings related to assets still held at end of period	(7,541)	(26,802)
Beginning Balance of other assets and other liabilities	2,244	(80)
Included In Earnings of other assets and other liabilities	20,444	18,022
Transfer in and/or out of Level 3 of other assets and other liabilities	(6,541)	(9,771)
Ending Balance of other assets and other liabilities	16,147	8,171
Changes in unrealized gains (losses) included in earnings related to other assets and other liabilities still held at end of period	16,036	7,630
Financial assets:
Cash and cash equivalents	982,305	1,043,669	933,755	$ 1,246,342
Interest-bearing deposits at banks	100,101		101,222
Trading account assets	413,737		523,834
Investment securities	6,507,165		7,150,540
Loans and leases:
Allowance for credit losses	(903,703)	(891,265)	(902,941)	$ (878,022)
Loans and leases, net	51,214,978		51,087,441
Financial liabilities:
Noninterest-bearing deposits	(15,219,562)		(14,557,568)
Time deposits	(5,508,432)		(5,817,170)
Deposits at Cayman Islands office	(1,063,670)		(1,605,916)
Long-term borrowings	(7,305,420)		(7,840,151)
Fair value assets and liabilities measured on nonrecurring basis (Textual) [Line Items]
Loans measured at fair value on nonrecurring basis	550,000	793,000
Fair Value Measurements (Textuals) [Abstract]
Amount of available-for-sale investment securities derecognized due to adoption of new accounting rules	$ 355,000
Number Of independent pricing sources used to value privately issued residential mortgage backed securities valued with internal modeling	2
Privately issued residential mortgage-backed securities with internal modeling, at cost	$ 1,400,000		1,500,000
Minimum range of Weightings applied to internal model valuations, in percentage	0.00%
Maximum range of Weightings applied to internal model valuations, in percentage	40.00%
Weighted-average reliance on internal model pricing, in percentage	34.00%
Average weighting placed on the values provided by the independent sources, in percentage	66.00%
Fair value of privately issued residential mortgage-backed securities valued with internal modeling	$ 1,300,000
Weighted-average market yield	8.30%
Securities issued by financial institutions and other entities backed by trust preferred securities at cost	$ 94,000		95,000
Fair value of securities issued by financial institutions and other entities backed by trust preferred securities	114,000		111,000
Change in fair value of nonrecurring fair value measured loans for charge-offs and impairment reserves	48,000	58,000
Assets taken in foreclosure of defaulted loans measured at fair value on a nonrecurring basis	34,000	17,000
Change in fair value of nonrecurring fair value measured foreclosed assets	9,000	10,000
U.S. Treasury and federal agencies [Member]
Assets measured at estimated fair value on a recurring basis [Line Items]
Investment securities	39,139		63,434
Obligations of states and political subdivisions [Member]
Assets measured at estimated fair value on a recurring basis [Line Items]
Investment securities	59,390		60,425
Government issued or guaranteed [Member]
Assets measured at estimated fair value on a recurring basis [Line Items]
Investment securities	2,839,861		3,306,241
Privately issued residential [Member]
Assets measured at estimated fair value on a recurring basis [Line Items]
Investment securities	1,391,878		1,435,561
Privately issued commercial [Member]
Assets measured at estimated fair value on a recurring basis [Line Items]
Investment securities	20,467		22,407
Collateralized Debt Obligations [Member]
Assets measured at estimated fair value on a recurring basis [Line Items]
Investment securities	114,265		110,756
Other Debt Securities [Member]
Assets measured at estimated fair value on a recurring basis [Line Items]
Investment securities	306,549		298,900
Equity Securities [Member]
Assets measured at estimated fair value on a recurring basis [Line Items]
Investment securities	83,435		115,768
Carrying Amount [Member]
Financial assets:
Cash and cash equivalents	982,305		933,755
Interest-bearing deposits at banks	100,101		101,222
Trading account assets	413,737		523,834
Investment securities	6,507,165		7,150,540
Loans and leases:
Commercial loans and leases	13,826,299		13,390,610
Commercial real estate loans	20,891,615		21,183,161
Residential real estate loans	6,154,960		5,928,056
Consumer loans	11,245,807		11,488,555
Allowance for credit losses	(903,703)		(902,941)
Loans and leases, net	51,214,978		51,087,441
Accrued interest receivable	220,922		202,182
Financial liabilities:
Noninterest-bearing deposits	(15,219,562)		(14,557,568)
Savings Deposits And NOW Accounts	(28,756,435)		(27,824,630)
Time deposits	(5,508,432)		(5,817,170)
Deposits at Cayman Islands office	(1,063,670)		(1,605,916)
Short term borrowings	(504,676)		(947,432)
Long-term borrowings	(7,305,420)		(7,840,151)
Accrued interest payable	(95,762)		(71,954)
Trading account liabilities	(303,930)		(333,222)
Other financial instruments:
Commitments to originate real estate loans for sale	16,147		2,244
Commitments to sell real estate loans	(2,499)		12,178
Other credit-related commitments	(68,108)		(74,426)
Interest rate swap agreements used for interest rate risk management	84,232		96,637
Calculated Estimate [Member]
Financial assets:
Cash and cash equivalents	982,305		933,755
Interest-bearing deposits at banks	100,101		101,222
Trading account assets	413,737		523,834
Investment securities	6,418,912		7,051,454
Loans and leases:
Commercial loans and leases	13,566,686		13,135,569
Commercial real estate loans	20,563,422		20,840,346
Residential real estate loans	5,876,173		5,699,028
Consumer loans	10,949,858		11,178,583
Allowance for credit losses	0		0
Loans and leases, net	50,956,139		50,853,526
Accrued interest receivable	220,922		202,182
Financial liabilities:
Noninterest-bearing deposits	(15,219,562)		(14,557,568)
Savings Deposits And NOW Accounts	(28,756,435)		(27,824,630)
Time deposits	(5,548,229)		(5,865,779)
Deposits at Cayman Islands office	(1,063,670)		(1,605,916)
Short term borrowings	(504,676)		(947,432)
Long-term borrowings	(7,442,997)		(7,937,397)
Accrued interest payable	(95,762)		(71,954)
Trading account liabilities	(303,930)		(333,222)
Other financial instruments:
Commitments to originate real estate loans for sale	16,147		2,244
Commitments to sell real estate loans	(2,499)		12,178
Other credit-related commitments	(68,108)		(74,426)
Interest rate swap agreements used for interest rate risk management	84,232		96,637
Quoted Prices in Active Markets for Identical Assets (Level 1) Member
Liabilities measured at estimated fair value on a recurring basis [Line Items]
Trading account liabilities	0		0
Other liabilities	0		0
Total liabilities	0		0
Significant Observable Inputs (Level 2) [Member]
Liabilities measured at estimated fair value on a recurring basis [Line Items]
Trading account liabilities	303,930		333,222
Other liabilities	3,993		3,024
Total liabilities	307,923		336,246
Significant Unobservable Inputs (Level 3) [Member]
Liabilities measured at estimated fair value on a recurring basis [Line Items]
Trading account liabilities	0		0
Other liabilities	120		583
Total liabilities	120		583
Significant Observable Inputs (Level 2) [Member]
Fair value assets and liabilities measured on nonrecurring basis (Textual) [Line Items]
Loans measured at fair value on nonrecurring basis	267,000	471,000
Significant Unobservable Inputs (Level 3) [Member]
Fair value assets and liabilities measured on nonrecurring basis (Textual) [Line Items]
Loans measured at fair value on nonrecurring basis	283,000	322,000
Collateralized Debt Obligations [Member]
Changes in Level 3 assets and liabilities measured at estimated fair value on a recurring basis
Beginning Balance	110,756	115,346
Included in earnings		(355)
Included in other comprehensive income	3,834	10,895
Purchases, sales, issuances and settlements	(325)	(131)
Ending Balance	114,265	125,755
Changes in unrealized gains (losses) included in earnings related to assets still held at end of period		(355)
Other Debt Securities [Member]
Changes in Level 3 assets and liabilities measured at estimated fair value on a recurring basis
Beginning Balance		420
Included in other comprehensive income		35
Ending Balance		$ 455
Quoted Prices in Active Markets for Identical Assets (Level 1) Member
Assets measured at estimated fair value on a recurring basis [Line Items]
Trading account assets	54,843		53,032
Investment securities	71,324		106,872
Real estate loans held for sale	0		0
Other assets	0		0
Total assets	126,167		159,904
Quoted Prices in Active Markets for Identical Assets (Level 1) Member \| U.S. Treasury and federal agencies [Member]
Assets measured at estimated fair value on a recurring basis [Line Items]
Investment securities	0		0
Quoted Prices in Active Markets for Identical Assets (Level 1) Member \| Obligations of states and political subdivisions [Member]
Assets measured at estimated fair value on a recurring basis [Line Items]
Investment securities	0		0
Quoted Prices in Active Markets for Identical Assets (Level 1) Member \| Government issued or guaranteed [Member]
Assets measured at estimated fair value on a recurring basis [Line Items]
Investment securities	0		0
Quoted Prices in Active Markets for Identical Assets (Level 1) Member \| Privately issued residential [Member]
Assets measured at estimated fair value on a recurring basis [Line Items]
Investment securities	0		0
Quoted Prices in Active Markets for Identical Assets (Level 1) Member \| Privately issued commercial [Member]
Assets measured at estimated fair value on a recurring basis [Line Items]
Investment securities	0		0
Quoted Prices in Active Markets for Identical Assets (Level 1) Member \| Collateralized Debt Obligations [Member]
Assets measured at estimated fair value on a recurring basis [Line Items]
Investment securities	0		0
Quoted Prices in Active Markets for Identical Assets (Level 1) Member \| Other Debt Securities [Member]
Assets measured at estimated fair value on a recurring basis [Line Items]
Investment securities	0		0
Quoted Prices in Active Markets for Identical Assets (Level 1) Member \| Equity Securities [Member]
Assets measured at estimated fair value on a recurring basis [Line Items]
Investment securities	71,324		106,872
Significant Observable Inputs (Level 2) [Member]
Assets measured at estimated fair value on a recurring basis [Line Items]
Trading account assets	358,894		470,802
Investment securities	3,257,050		3,737,896
Real estate loans held for sale	188,573		544,567
Other assets	85,726		111,839
Total assets	3,890,243		4,865,104
Significant Observable Inputs (Level 2) [Member] \| U.S. Treasury and federal agencies [Member]
Assets measured at estimated fair value on a recurring basis [Line Items]
Investment securities	39,139		63,434
Significant Observable Inputs (Level 2) [Member] \| Obligations of states and political subdivisions [Member]
Assets measured at estimated fair value on a recurring basis [Line Items]
Investment securities	59,390		60,425
Significant Observable Inputs (Level 2) [Member] \| Government issued or guaranteed [Member]
Assets measured at estimated fair value on a recurring basis [Line Items]
Investment securities	2,839,861		3,306,241
Significant Observable Inputs (Level 2) [Member] \| Privately issued residential [Member]
Assets measured at estimated fair value on a recurring basis [Line Items]
Investment securities	0		0
Significant Observable Inputs (Level 2) [Member] \| Privately issued commercial [Member]
Assets measured at estimated fair value on a recurring basis [Line Items]
Investment securities	0		0
Significant Observable Inputs (Level 2) [Member] \| Collateralized Debt Obligations [Member]
Assets measured at estimated fair value on a recurring basis [Line Items]
Investment securities	0		0
Significant Observable Inputs (Level 2) [Member] \| Other Debt Securities [Member]
Assets measured at estimated fair value on a recurring basis [Line Items]
Investment securities	306,549		298,900
Significant Observable Inputs (Level 2) [Member] \| Equity Securities [Member]
Assets measured at estimated fair value on a recurring basis [Line Items]
Investment securities	12,111		8,896
Significant Unobservable Inputs (Level 3) [Member]
Assets measured at estimated fair value on a recurring basis [Line Items]
Trading account assets	0		0
Investment securities	1,526,610		1,568,724
Real estate loans held for sale	0		0
Other assets	16,267		2,827
Total assets	1,542,877		1,571,551
Significant Unobservable Inputs (Level 3) [Member] \| U.S. Treasury and federal agencies [Member]
Assets measured at estimated fair value on a recurring basis [Line Items]
Investment securities	0		0
Significant Unobservable Inputs (Level 3) [Member] \| Obligations of states and political subdivisions [Member]
Assets measured at estimated fair value on a recurring basis [Line Items]
Investment securities	0		0
Significant Unobservable Inputs (Level 3) [Member] \| Government issued or guaranteed [Member]
Assets measured at estimated fair value on a recurring basis [Line Items]
Investment securities	0		0
Significant Unobservable Inputs (Level 3) [Member] \| Privately issued residential [Member]
Assets measured at estimated fair value on a recurring basis [Line Items]
Investment securities	1,391,878		1,435,561
Significant Unobservable Inputs (Level 3) [Member] \| Privately issued commercial [Member]
Assets measured at estimated fair value on a recurring basis [Line Items]
Investment securities	20,467		22,407
Significant Unobservable Inputs (Level 3) [Member] \| Collateralized Debt Obligations [Member]
Assets measured at estimated fair value on a recurring basis [Line Items]
Investment securities	114,265		110,756
Significant Unobservable Inputs (Level 3) [Member] \| Other Debt Securities [Member]
Assets measured at estimated fair value on a recurring basis [Line Items]
Investment securities	0		0
Significant Unobservable Inputs (Level 3) [Member] \| Equity Securities [Member]
Assets measured at estimated fair value on a recurring basis [Line Items]
Investment securities	$ 0		$ 0

Commitments and contingencies (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2011	Dec. 31, 2010
Commitments to extend credit
Home equity lines of credit	$ 6,274,649	$ 6,281,366
Commercial real estate loans to be sold	422,511	72,930
Other commercial real estate and construction	1,779,514	1,672,006
Residential real estate loans to be sold	438,283	161,583
Other residential real estate	112,328	151,111
Commercial and other	8,816,887	8,332,199
Standby letters of credit	3,852,506	3,917,318
Commercial letters of credit	58,805	76,962
Financial guarantees and indemnification contracts	1,707,670	1,609,944
Commitments to sell real estate loans	889,631	734,696
Commitments and contingencies (Textuals) [Abstract]
Maximum credit risk for recourse associated with loans sold under Federal National Mortgage Association Delegated Underwriting and Servicing program	1,600,000	$ 1,600,000
Outstanding loan principal balances reinsured	82,000
Assets of subsidiaries providing reinsurance to satisfy claims	53,000
2011 - 2013 [Member]
Company's significant commitments
Naming rights of football stadium per year	5,000
2014 - 2017 [Member]
Company's significant commitments
Naming rights of football stadium per year	$ 6,000

Segment information (Details) - USD ($)	3 Months Ended		12 Months Ended
Segment information (Details) - USD ($)	Mar. 31, 2011	Mar. 31, 2010	Dec. 31, 2010
Information about the Company's segments
Total Revenue	$ 883,224,000	$ 814,040,000
Net income (loss)	206,273,000	150,955,000
Summary of segment information
Average total assets	68,045,000,000	68,883,000,000	$ 68,380,000,000
Segment information (Textuals) [Abstract]
Taxable Equivalent Adjustment	6,327,000	5,923,000
Business Banking [Member]
Information about the Company's segments
Total Revenue	99,777,000	101,796,000
Inter-segment revenues	962,000
Net income (loss)	26,300,000	25,344,000
Summary of segment information
Average total assets	4,754,000,000	4,959,000,000	4,843,000,000
Commercial Banking [Member]
Information about the Company's segments
Total Revenue	213,612,000	192,406,000
Inter-segment revenues	1,166,000
Net income (loss)	88,331,000	76,868,000
Summary of segment information
Average total assets	16,114,000,000	15,509,000,000	15,461,000,000
Commercial Real Estate [Member]
Information about the Company's segments
Total Revenue	125,306,000	110,413,000
Inter-segment revenues	356,000	18,000
Net income (loss)	49,010,000	43,753,000
Summary of segment information
Average total assets	13,635,000,000	13,368,000,000	13,194,000,000
Discretionary Portfolio [Member]
Information about the Company's segments
Total Revenue	42,483,000	(12,233,000)
Inter-segment revenues	(7,787,000)	(2,747,000)
Net income (loss)	16,127,000	(16,162,000)
Summary of segment information
Average total assets	13,931,000,000	14,571,000,000	14,690,000,000
Residential Mortgage Banking [Member]
Information about the Company's segments
Total Revenue	57,848,000	63,117,000
Inter-segment revenues	10,307,000	8,197,000
Net income (loss)	4,785,000	595,000
Summary of segment information
Average total assets	2,045,000,000	2,222,000,000	2,217,000,000
Retail Banking [Member]
Information about the Company's segments
Total Revenue	295,048,000	307,475,000
Inter-segment revenues	2,987,000	2,687,000
Net income (loss)	52,726,000	59,037,000
Summary of segment information
Average total assets	11,653,000,000	12,272,000,000	12,079,000,000
All Other [Member]
Information about the Company's segments
Total Revenue	49,150,000	51,066,000
Inter-segment revenues	(7,991,000)	(8,155,000)
Net income (loss)	(31,006,000)	(38,480,000)
Summary of segment information
Average total assets	$ 5,913,000,000	$ 5,982,000,000	$ 5,896,000,000

Relationship with Bayview Lending Group LLC and Bayview Financial Holdings, L.P. (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2011	Mar. 31, 2010	Dec. 31, 2010
Relationship with Bayview Lending Group LLC and Bayview Financial Holdings, L.P. (Textuals) [Abstract]
Minority interest in Bayview Lending Group LLC	20.00%
Carrying value of minority interest investment in Bayview Lending Group LLC	$ 212
Outstanding principal balances of commercial mortgage loans from BLG and Bayview Financial	5,100		$ 5,200
Amounts recorded as capitalized servicing assets for commercial mortgage loans	23		26
Servicing rights purchased from Bayview Financial related to residential mortgage loans	8		9
Outstanding principal balances of residential mortgage loans from Bayview Financial	3,500		3,600
Revenues from servicing residential and small balance commercial mortgage loans purchased from BLG and Bayview Financial	11	$ 12
Collateralized mortgage obligations in available-for-sale investment securities portfolio securitized by Bayview Financial	20		22
Investment securities in held-to-maturity portfolio securitized by Bayview Financial	$ 300		$ 313

Label	Element	Value
Mortgage Backed Securities Issued By Private Enterprises Residential Member
Held-to-maturity Securities, Fair Value	us-gaap_HeldToMaturitySecuritiesFairValue	$ 198,140,000
Held-to-maturity Securities, Fair Value	us-gaap_HeldToMaturitySecuritiesFairValue	199,034,000
Held-to-maturity Securities, Unrecognized Holding Losses	us-gaap_HeldToMaturitySecuritiesUnrecognizedHoldingLosses	114,397,000
Held-to-maturity Securities, Unrecognized Holding Losses	us-gaap_HeldToMaturitySecuritiesUnrecognizedHoldingLosses	100,746,000
Held to maturity (fair value: $431,036 at September 30, 2009; $394,752 at December 31, 2008)	us-gaap_HeldToMaturitySecurities	312,537,000
Held to maturity (fair value: $431,036 at September 30, 2009; $394,752 at December 31, 2008)	us-gaap_HeldToMaturitySecurities	299,780,000
Government issued or guaranteed [Member]
Held-to-maturity Securities, Fair Value	us-gaap_HeldToMaturitySecuritiesFairValue	822,169,000
Held-to-maturity Securities, Fair Value	us-gaap_HeldToMaturitySecuritiesFairValue	770,354,000
Held to maturity (fair value: $431,036 at September 30, 2009; $394,752 at December 31, 2008)	us-gaap_HeldToMaturitySecurities	808,108,000
Held to maturity (fair value: $431,036 at September 30, 2009; $394,752 at December 31, 2008)	us-gaap_HeldToMaturitySecurities	758,611,000
Held-to-maturity Securities, Unrecognized Holding Gains	us-gaap_HeldToMaturitySecuritiesUnrecognizedHoldingGains	14,061,000
Held-to-maturity Securities, Unrecognized Holding Gains	us-gaap_HeldToMaturitySecuritiesUnrecognizedHoldingGains	11,743,000
Mortgage Backed Securities Issued By Private Enterprises Residential Member
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings	us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInEarnings	26,447,000
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings	us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInEarnings	7,541,000
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income	us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInOtherComprehensiveIncome	74,454,000
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income	us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInOtherComprehensiveIncome	61,085,000
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue	2,064,904,000
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue	1,664,341,000
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue	1,435,561,000
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue	1,391,878,000
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Still Held Gain Loss In Earnings	mtb_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetStillHeldGainLossInEarnings	(26,447,000)
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Still Held Gain Loss In Earnings	mtb_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetStillHeldGainLossInEarnings	(7,541,000)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers, Net	us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetTransfersNet	(355,248,000)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases, Sales, Issuances, Settlements	us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPurchasesSalesIssuancesSettlements	93,322,000
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases, Sales, Issuances, Settlements	us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPurchasesSalesIssuancesSettlements	97,227,000
Mortgage Backed Securities Issued By Private Enterprises Commercial Member
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income	us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInOtherComprehensiveIncome	2,073,000
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income	us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInOtherComprehensiveIncome	(82,000)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue	25,166,000
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue	25,125,000
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue	22,407,000
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue	20,467,000
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases, Sales, Issuances, Settlements	us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPurchasesSalesIssuancesSettlements	2,114,000
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases, Sales, Issuances, Settlements	us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPurchasesSalesIssuancesSettlements	1,858,000
Foreign exchange and other option and futures contracts [Member]
Gain (Loss) on Derivative Instruments Held for Trading Purposes, Net	us-gaap_GainLossOnDerivativeInstrumentsHeldForTradingPurposesNet	342,000
Gain (Loss) on Derivative Instruments Held for Trading Purposes, Net	us-gaap_GainLossOnDerivativeInstrumentsHeldForTradingPurposesNet	(548,000)
Interest rate contracts [Member]
Gain (Loss) on Derivative Instruments Held for Trading Purposes, Net	us-gaap_GainLossOnDerivativeInstrumentsHeldForTradingPurposesNet	(614,000)
Gain (Loss) on Derivative Instruments Held for Trading Purposes, Net	us-gaap_GainLossOnDerivativeInstrumentsHeldForTradingPurposesNet	$ 475,000

Loans and leases and the allowance for credit losses (Details 7) - USD ($) $ in Thousands	Mar. 31, 2011	Dec. 31, 2010
Recorded investment in loans and leases on the basis of the Company's impairment methodology
Loans and leases, net of unearned discount	$ 52,118,681	$ 51,990,382
Commercial, financial, leasing [Member]
Recorded investment in loans and leases on the basis of the Company's impairment methodology
Loans and leases, net of unearned discount	13,826,299	13,390,610
Commercial real estate loans [Member]
Recorded investment in loans and leases on the basis of the Company's impairment methodology
Loans and leases, net of unearned discount	20,891,615	21,183,161
Residential real estate loans [Member]
Recorded investment in loans and leases on the basis of the Company's impairment methodology
Loans and leases, net of unearned discount	6,154,960	5,928,056
Consumer loans [Member]
Recorded investment in loans and leases on the basis of the Company's impairment methodology
Loans and leases, net of unearned discount	11,245,807	11,488,555
Individually evaluated for impairment [Member]
Recorded investment in loans and leases on the basis of the Company's impairment methodology
Loans and leases, net of unearned discount	1,189,086	1,227,553
Individually evaluated for impairment [Member] \| Commercial, financial, leasing [Member]
Recorded investment in loans and leases on the basis of the Company's impairment methodology
Loans and leases, net of unearned discount	173,188	186,739
Individually evaluated for impairment [Member] \| Commercial real estate loans [Member]
Recorded investment in loans and leases on the basis of the Company's impairment methodology
Loans and leases, net of unearned discount	658,462	682,120
Individually evaluated for impairment [Member] \| Residential real estate loans [Member]
Recorded investment in loans and leases on the basis of the Company's impairment methodology
Loans and leases, net of unearned discount	285,106	286,612
Individually evaluated for impairment [Member] \| Consumer loans [Member]
Recorded investment in loans and leases on the basis of the Company's impairment methodology
Loans and leases, net of unearned discount	72,330	72,082
Collectively evaluated for impairment [Member]
Recorded investment in loans and leases on the basis of the Company's impairment methodology
Loans and leases, net of unearned discount	50,841,006	50,665,810
Collectively evaluated for impairment [Member] \| Commercial, financial, leasing [Member]
Recorded investment in loans and leases on the basis of the Company's impairment methodology
Loans and leases, net of unearned discount	13,651,189	13,201,621
Collectively evaluated for impairment [Member] \| Commercial real estate loans [Member]
Recorded investment in loans and leases on the basis of the Company's impairment methodology
Loans and leases, net of unearned discount	20,155,583	20,417,958
Collectively evaluated for impairment [Member] \| Residential real estate loans [Member]
Recorded investment in loans and leases on the basis of the Company's impairment methodology
Loans and leases, net of unearned discount	5,862,957	5,632,124
Collectively evaluated for impairment [Member] \| Consumer loans [Member]
Recorded investment in loans and leases on the basis of the Company's impairment methodology
Loans and leases, net of unearned discount	11,171,277	11,414,107
Purchased Impaired [Member]
Recorded investment in loans and leases on the basis of the Company's impairment methodology
Loans and leases, net of unearned discount	88,589	97,019
Purchased Impaired [Member] \| Commercial, financial, leasing [Member]
Recorded investment in loans and leases on the basis of the Company's impairment methodology
Loans and leases, net of unearned discount	1,922	2,250
Purchased Impaired [Member] \| Commercial real estate loans [Member]
Recorded investment in loans and leases on the basis of the Company's impairment methodology
Loans and leases, net of unearned discount	77,570	83,083
Purchased Impaired [Member] \| Residential real estate loans [Member]
Recorded investment in loans and leases on the basis of the Company's impairment methodology
Loans and leases, net of unearned discount	6,897	9,320
Purchased Impaired [Member] \| Consumer loans [Member]
Recorded investment in loans and leases on the basis of the Company's impairment methodology
Loans and leases, net of unearned discount	$ 2,200	$ 2,366