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Equipment Finance Loan [Member] Non-credit (discount) Provision for credit losses Provision for Loan and Lease Losses ASU 2014-09 [Member] Accounting Standards Update 2014-09 [Member] Collateralized Debt Obligations [Member] Collateralized Debt Obligations [Member] Debt securities available for sale: Debt Securities, Available-for-Sale, Amortized Cost, Fiscal Year Maturity [Abstract] Debt Instruments [Abstract] Available for sale (cost: $12,396 at March 31, 2024; $10,691 at December 31, 2023) Debt Securities, Available-for-Sale Investment securities available for sale, estimated fair value Total Unrealized losses on cash flow hedges, net of tax Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification, after Tax Cash Flow Hedges [Member] Cash Flow Hedges [Member] Cash flow hedges. Commercial Real Estate Loans [Member] Commercial real estate loans. Schedule Of Segment Reporting Information By Segment [Table] Schedule of Segment Reporting Information, by Segment [Table] Preferred Stock, Dividend Payment Terms Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] Fair Value, Inputs, Level 1 [Member] Commitments to Originate Real Estate Loans for Sale [Member] Mortgage Related Commitments To Originate Real Estate Loans For Sale [Member] Mortgage related commitments to originate real estate loans for sale. Increase (Decrease) in Other Operating Assets and Liabilities, Net, Total Net change in other accrued income and expense Increase (Decrease) in Other Operating Assets and Liabilities, Net Net increase (decrease) in short-term borrowings Net Increase Decrease In Short Term Borrowings Net increase (decrease) in short term borrowings. 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Trading account and other non-hedging derivative gains Trading Gain (Loss), Total Trading Gain (Loss) Senior notes Senior Notes Senior Notes, Total Summary of Sources of Noninterest Income that are Subject to Revenue Recognition Accounting Guidance Disaggregation of Revenue [Table Text Block] Total of investment securities, fair value, 12 Months or More Investment Securities Continuous Unrealized Loss Position Twelve Months Or Longer Fair Value This item represents the fair value of securities that have been in a continuous loss position for twelve months or longer. Interest Income Recognized Impaired Financing Receivable Nonaccrual Interest Income Impaired financing receivable nonaccrual interest income. 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Long-term Borrowings [Member] Long-term Debt [Member] Long-Term Debt [Member] Schedule Of Business Acquisitions By Acquisition [Table] Schedule of Business Acquisitions, by Acquisition [Table] Net Interest Income Net interest income Interest Income (Expense), Net Summary of Identifiable Assets Acquired, Liabilities Assumed and Preferred Stock Exchanged as of Acquisition Schedule of Recognized Identified Assets Acquired and Liabilities Assumed [Table Text Block] Financing Receivable, Modifications [Line Items] Financing Receivable, Modified [Line Items] Estimated fair value, Less than 12 months Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, Less than 12 Months Federal funds sold Federal Funds Sold Financial liabilities: Financial Instruments, Financial Liabilities, Balance Sheet Groupings [Abstract] Pledging Purpose [Axis] Preferred Series E [Member] Series E Preferred Stock [Member] Amortized Cost with Allowance Amortized Cost without Allowance Impaired Financing Receivable, with Related Allowance, Unpaid Principal Balance Changes in Level 3 Assets and Liabilities Measured at Estimated Fair Value on Recurring Basis Changes In Level Three Assets And Liabilities Measured At Estimated Fair Value On Recurring Basis Table [Text Block] The tabular disclosure of changes in level 3 assets and liabilities measured at estimated fair value on recurring basis. Schedule Of Financing Receivable Recorded Investment Credit Quality Indicator [Table] Financing Receivable, Credit Quality Indicator [Table] Loans measured at fair value on nonrecurring basis Loans Receivable, Fair Value Disclosure Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Amortization of Prior Service Cost (Credit), Statement of Income or Comprehensive Income [Extensible Enumeration] Other Revenues From Operations [Member] Other Revenues From Operations [Member] Other revenues from operations. Assets and Liabilities Measured at Estimated Fair Value on Recurring Basis Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block] Due after ten years Debt Securities, Held-to-Maturity, Amortized Cost, after Allowance for Credit Loss, Maturity, Allocated and Single Maturity Date, after Year 10 Common stock per share dividend amount Common Stock, Dividends, Per Share, Cash Paid Financial Asset, Aging Financial Asset, Aging [Domain] Schedule of Stock by Class [Table] Gross charge-offs Loans and Leases Receivable, gross writeoffs Loans and leases receivable gross writeoffs. Fair Value Measurement Fair Value Measurement [Domain] Derivatives in fair value hedging relationships, Hedged item Gain Loss On Hedged Item In Fair Value Hedge Aggregate net gain and losses (whether realized or unrealized) of the hedged item in a fair value hedge recognized in the income statement. Expected return on plan assets Defined Benefit Plan, Expected Return (Loss) on Plan Assets Loans secured by residential real estate that were in the process of foreclosure Residential Mortgage Loans Secured By Residential Real Estate In Process Of Foreclosure Residential mortgage loans secured by residential real estate in process of foreclosure. Total liabilities Liabilities, Fair Value Disclosure Class of Stock [Line Items] Trading account Debt Securities, Trading, and Equity Securities, FV-NI, Total Debt Securities, Trading, and Equity Securities, FV-NI Balance Sheet Location Balance Sheet Location [Axis] Mortgage-backed securities Debt Securities, Held-to-Maturity, Amortized Cost, after Allowance for Credit Loss, Maturity, without Single Maturity Date Schedule Of Accounts Notes Loans And Financing Receivable [Table] Schedule of Accounts, Notes, Loans and Financing Receivable [Table] Summary of Loan grades applied various classes of Commercial and Industrial Loans and Commercial Real Estate Loans Summary Of Loan Grades Applied Various Classes Of Commercial And Real Estate Loans Table [Text Block] Summary of loan grades applied various classes of commercial and real estate loans. Extinguishment of Debt, Type Extinguishment of Debt, Type [Domain] Financial Asset, Aging Financial Asset, Aging [Axis] Federal Home Loan Bank Stock and Federal Reserve Bank Stock, Total Other securities, Estimated fair value Federal Home Loan Bank Stock and Federal Reserve Bank Stock Total liabilities and shareholders’ equity Liabilities and Equity Entity Address, State or Province Entity Address, State or Province Derivative financial instruments Derivative Instruments and Hedging Activities Disclosure [Text Block] Conversion of Series H preferred stock Stock Issued During Period, Value, New Issues Total comprehensive income Total comprehensive income Comprehensive Income (Loss), Net of Tax, Attributable to Parent Accrued interest and other assets Interest Receivable and Other Assets Trading Symbol Trading Symbol Net income available to common equity Net Income Loss Available To Common Stockholders Basic Before Unvested Stock Based Compensation Awards Adjustment Net income loss available to common stockholders before unvested stock based compensation awards adjustment as used in the determination of basic earnings per common share. Debt Instrument, Redemption, Period Debt Instrument, Redemption, Period [Axis] Other [Member] Other Modifications [Member] Other modifications. Common stock, shares issued Common Stock, Shares, Issued Loan and Leases Considered Nonaccrual and Interest Income Recognized on Loans Loan And Leases Considered Nonaccrual And Interest Income Recognized On Loans Table [Text Block] Loan and leases considered nonaccrual and interest income recognized on loans. Consolidated Entities Consolidated Entities [Domain] Preferred Series G [Member] Series G Preferred Stock [Member] Other revenues from operations: Other Revenues From Operations [Abstract] Other revenues from operations. Schedule of Long-Term Debt Instruments [Table] Pre-modification Recorded Investment Financing Receivable, Troubled Debt Restructuring, Premodification Collateral relating to net asset positions Derivative Asset, Fair Value of Collateral Accumulated Other Comprehensive Income (Loss), Net [Member] AOCI Attributable to Parent [Member] Divestiture Business Combination Disclosure [Text Block] Total other comprehensive income (loss) Other Comprehensive Income (Loss), Net of Tax Net loss during period Loss contingency expense amount Loss Contingency Expense Amount Loss contingency expense amount. Accumulated Other Comprehensive Income (Loss) [Line Items] Accumulated Other Comprehensive Income (Loss) [Line Items] Number of debt securities with aggregate gross unrealized losses Number Of Debt Securities With Gross Losses Number of debt securities with gross losses. Renewable Energy Investments [Member] Renewable Energy Investments [Member] Renewable energy investments. Series F And Series G Preferred Stock [Member] Series F And Series G Preferred Stock [Member] Series F And Series G Preferred Stock Entity Address, City or Town Entity Address, City or Town Term Loans 2018 [Member] Term Loans 2018 [Member] Long Term Debt Two Thousand Eighteen [Member] Long term debt two thousand eighteen. Acquisition, net of cash consideration, Bank and bank holding company Proceeds from Previous Acquisition Interest-bearing deposits at banks Interest-Bearing Deposits in Banks and Other Financial Institutions Computations of Basic Earnings Per Common Share Schedule of Earnings Per Share, Basic, by Common Class, Including Two Class Method [Table Text Block] Summary of Investment Holdings [Line Items] Borrowings Debt Disclosure [Text Block] Unrealized holding gains (losses), net, tax OCI, Debt Securities, Available-for-Sale, Unrealized Holding Gain (Loss), before Adjustment, Tax Disposal Group Name [Axis] Held To Maturity Securities Continuous Unrealized Loss Position Less Than12 Months Aggregate Losses Debt Securities, Held-to-Maturity, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss Dividends paid — common Payments of Ordinary Dividends, Common Stock Depreciation and amortization of premises and equipment Depreciation And Amortization1 Depreciation and amortization of premises and equipment. Subsequent Event [Member] Subsequent Event [Member] Subsequent Event Type Subsequent Event Type [Axis] Interest Payments On Variable Rate Commercial Real Estate Loans [Member] Interest Payments On Variable Rate Commercial Real Estate Loans [Member] Interest payments on variable rate commercial real estate loans. Amount of agreements to repurchase securities Securities Borrowed Securities Borrowed, Total Additional Paid-in Capital [Member] Additional Paid-in Capital [Member] Proceeds from maturities of investment securities Available for sale Proceeds from Maturities, Prepayments and Calls of Debt Securities, Available-for-Sale Commitments and Contingent Liabilities Outstanding Commitments Table [Text Block] The tabular disclosure of commitments. Guaranteed by Government-Related Entities [Member] Loans Insured or Guaranteed by US Government Authorities [Member] Certificates issued Debt Instrument, Issued, Principal Estimated fair value, 12 months or more Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, 12 Months or Longer Net yield adjustment from cash flow hedges currently in effect, before tax Other Comprehensive Income Loss Net Yield Adjustment From Cash Flow Hedges Before Tax Other comprehensive income loss net yield adjustment from cash flow hedges, before tax. Preferred stock, par value Preferred Stock, Par or Stated Value Per Share Investments which met the eligibility criteria Investments Met Eligiblity Criteria Investments met eligiblity criteria. Statement of Stockholders' Equity [Abstract] Net increase in loans and leases Payments for (Proceeds from) Loans and Leases, Total Payments for (Proceeds from) Loans and Leases Financing receivable allowance for credit losses net write offs. Financing Receivable Allowance For Credit Losses Net Write Offs [Abstract] Net charge-offs Reduction in estimated fair value of interest rate contracts in asset position Increase Decrease In Estimated Fair Value Of Interest Rate Contracts In Asset Position Increase (decrease) in estimated fair value of interest rate contracts in asset position. 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Outstanding principal balances of mortgage servicing rights Mortgage Loans Of Privately Held Company Mortgage servicing rights of commercial mortgage loans with outstanding principal balances of privately held commercial mortgage company. Accumulated Other Adjustment [Member] Accumulated Other Adjustment [Member] Accumulated other adjustment. Statement of Comprehensive Income [Abstract] Treasury stock, common shares Treasury Stock, Common, Shares Accrued Interest and Other Assets [Member] Accrued Interest and Other Assets [Member] Accrued interest and other assets. Entity Central Index Key Entity Central Index Key Forward-Starting Interest Rate Swap Agreements [Member] Forward Starting Interest Rate Swap Agreements [Member] Forward starting interest rate swap agreements. U.S. Treasury and Federal Agencies [Member] US Treasury and Government [Member] Loans and leases and the allowance for credit losses Loans, Notes, Trade and Other Receivables Disclosure [Text Block] Total assets Assets, Fair Value Disclosure Financial assets: Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract] Preferred stock, Shares Outstanding Preferred Stock, Shares Outstanding, Ending Balance Preferred Stock, Shares Outstanding, Beginning Balance Preferred stock, shares outstanding Preferred Stock, Shares Outstanding Period of satisfaction of contract with customer Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period Investment securities held to maturity Held to maturity (fair value: $13,865 at March 31, 2024; $14,308 at December 31, 2023) Amortized cost for held to maturity Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss Beginning balance, tax Ending balance, tax Accumulated Other Comprehensive Income Loss Income Tax The tax effect of the accumulated change in equity from transactions and other events and circumstances from non-owner sources. Excludes the tax effect of Net Income (Loss), and accumulated changes in equity from transactions resulting from investments by owners and distributions to owners. Includes the tax effect of foreign currency translation items, certain pension adjustments, unrealized gains and losses on certain investments in debt and equity securities, other than temporary impairment (OTTI) losses related to factors other than credit losses on available-for-sale and held-to-maturity debt securities that an entity does not intend to sell and it is not more likely than not that the entity will be required to sell before recovery of the amortized cost basis, as well as changes in the fair value of derivatives related to the effective portion of a designated cash flow hedge. Commercial and Industrial [Member] Commercial and Industrial [Member] Commercial and industrial. 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Income before taxes Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest Long-Term Debt, Excluding Current Maturities [Abstract] Long-term borrowings Financial Instruments Financial Instruments [Domain] Financing Receivable, Held-for-Sale, Not Part of Disposal Group, after Valuation Allowance, Ending Balance Financing Receivable, Held-for-Sale, Not Part of Disposal Group, after Valuation Allowance, Beginning Balance Mortgage loans held for sale Financing Receivable, Held-for-Sale, Not Part of Disposal Group, after Valuation Allowance Variable Interest Entity Disclosure [Abstract] Variable interest entity disclosure. Recurring fair value measurements for certain Level 3 Assets and Liabilities Beginning Balance Ending Balance Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value Fair Values Derivatives Balance Sheet Location By Derivative Contract Type By Hedging Designation [Table] Fair Values Derivatives, Balance Sheet Location, by Derivative Contract Type [Table] Investment, Name Investment, Name [Axis] Commitments to extend credit Commitments To Extend Credit [Abstract] Commitments to extend credit. Total other comprehensive income (loss) before reclassifications, tax Other Comprehensive Income (Loss) before Reclassifications, Tax Accrued interest and other liabilities [Member] Other Liabilities [Member] Term Loans 2021 [Member] Long Term Debt Two Thousand Twenty One [Member] Long term debt two thousand twenty one. Financing receivable, modifications other than troubled debt restructuring Financing receivable, modifications other than troubled debt restructuring. Trading account liabilities Trading account liabilities Trading Liabilities, Fair Value Disclosure Total available for sale (fair value) Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Fair Value Derivative Instrument Derivative Instrument [Axis] Total assets Total assets of partnerships in which the company invested Assets Assets MT [Member] M T [Member] M&T member Loans held for investment transferred to loans held for sale Loan, Transfer from Held-for-Sale to Held-in-Portfolio Other securities, Gross unrealized gains Other Securities Gross Unrealized Gains Other securities gross unrealized gains. Interest expense Interest Expense [Abstract] Summary of Merger Related Expenses Summary of merger-related expenses [Table Text Block] Summary of merger-related expenses. Readily marketable securities Amortized cost Readily Marketable Securities At Fair Value Amortized Cost Readily marketable securities at fair value amortized cost. Entity Registrant Name Entity Registrant Name Asset-Backed Notes [Member] Asset-Backed Securities [Member] Estimated uninsured deposits Cash, Uninsured Amount Debt Securities, Unrealized Gain (Loss), Total Unrealized losses on individual debt securities Debt Securities, Unrealized Gain (Loss) Weighted-average reduction Loans receiving interest rate, weighted-average reduction Loans receiving interest rate, weighted-average reduction. Retained Earnings (Accumulated Deficit), Total Retained earnings Retained Earnings (Accumulated Deficit) Unrealized Losses Less Than 12 Months Available For Sale Securities Continuous Unrealized Losses Position Less Than Twelve Months Aggregate Losses Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss Fully taxable Interest Income, Securities, Operating, Taxable Supplemental disclosure of cash flow information Supplemental Cash Flow Information [Abstract] Long-Term Federal Home Loan Bank Advances Long-Term Federal Home Loan Bank Advances, Total FHLB Advances Residential [Member] Residential Real Estate Excluding Alt A [Member] Residential real estate excluding Alt-A. Retained Earnings [Member] Retained Earnings [Member] Class of Stock Class of Stock [Axis] Unrealized losses on cash flow hedges, tax Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification, Tax Minimum [Member] Minimum [Member] Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items] Financing receivable, modifications other than troubled debt restructuring. Revenues, Total Total Revenues Revenues Revenues M&T Bank [Member] Parent [Member] Significant accounting policies Significant Accounting Policies [Text Block] Derivative Instruments and Hedging Activities Disclosure [Abstract] Commercial Mortgage-Backed Securities [Member] Commercial [Member] Commercial Mortgage-Backed Securities [Member] Derivative Liability, Subject to Master Netting Arrangement, before Offset of Collateral, Total Aggregate fair value of derivative financial instruments in a liability position Derivative Liability, Subject to Master Netting Arrangement, before Offset of Collateral Residential Mortgage Banking [Member] Residential Mortgage Banking [Member] Residential mortgage banking segment. Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Table] Fair Value Measurement Inputs and Valuation Techniques [Table] Equity Component Equity Component [Domain] Segments Segments [Axis] Range of reasonably possible losses Loss Contingency, Estimate of Possible Loss Receivables [Abstract] Series F fixed-to-floating rate non-cumulative perpetual preferred stock. Series F Fixed To Floating Rate Non Cumulative Perpetual Preferred Stock [Member] Series F Fixed-to-Floating Rate Non-Cumulative Perpetual Preferred Stock [Member] Interest received during the period Proceeds from Interest Received Cash and Due from Banks, Total Cash and due from banks Cash and Due from Banks Schedule Of Amortized Cost And Estimated Fair Value Of Investment Securities [Line Items] Schedule Of Amortized Cost And Estimated Fair Value Of Investment Securities [Line Items] Schedule of amortized cost and estimated fair value of investment securities. Percentage of income taxes receivable or payable Percentage of Income Taxes Receivable or Payable Percentage of income taxes receivable or payable. Weighted-average remaining term Loans and leases weighted-average remaining term Loans and leases weighted-average remaining term Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Adjustments to reconcile net income to net cash provided by operating activities: Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Criticized Nonaccrual [Member] Criticized Nonaccrual [Member] Criticized nonaccrual. Measurement Frequency Measurement Frequency [Axis] Debt Disclosure [Abstract] Net income available to common shareholders Diluted Net Income (Loss) Available to Common Stockholders, Diluted Loans Insured or Guaranteed by Government Authorities [Axis] Marketable Securities [Abstract] Investment securities Maturing at Various Dates Through 2039 [Member] Maturing at various dates through 2039 [Member] Maturing at various dates through 2039 [Member] Variable interest rate of debt instrument Debt Instrument, Basis Spread on Variable Rate Entity Current Reporting Status Entity Current Reporting Status Other, net Proceeds from (Payments for) Other Financing Activities Common stock, shares authorized Common Stock, Shares Authorized Fair Value By Balance Sheet Grouping [Table] Fair Value, by Balance Sheet Grouping [Table] Loan Modification Activities that were Considered Troubled Debt Restructurings Financing Receivable, Modified [Table Text Block] Purchases of investment securities equity and other Payments To Acquire Equity And Other Securities Investments Payments to acquire equity and other securities investments. Assets Assets [Abstract] Computations of Diluted Earnings Per Common Share Schedule of Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Table Text Block] Common stock awards converted Stock Issued During Period, Value, Conversion of Units Hedging Relationship Hedging Relationship [Axis] Savings and interest-checking deposits Savings and interest-checking deposits Savings And Interest Checking Deposits Amount of domestic interest-bearing checking and savings accounts, which may include money market accounts, NOW accounts, interest-bearing corporate checking accounts, brokered deposits and other savings accounts. Amortization of core deposit and other intangible assets Amortization of Intangible Assets SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate, Loan Type [Domain] Schedule of Carrying Amount of Investments In Tax Equity Partnerships and Related Future Funding Commitments Schedule of Carrying Amount of Investments in Tax Equity Partnerships [Table Text Block] Schedule of carrying amount of investments in tax equity partnerships. Other [Member] Other [Member] Other. Held to maturity, Estimated fair value, Less than 12 months Debt Securities, Held-to-Maturity, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value Common stock, $0.50 par, 250,000,000 shares authorized, 179,436,779 shares issued at March 31, 2024 and December 31, 2023 Common Stock, Value, Issued Post collateral requirements relating to positions Derivative Liability, Fair Value of Collateral Repayments of Long-Term Debt, Total Payments on long-term borrowings Repayments of Long-Term Debt Interest Expense, Time Deposits, Total Time deposits Interest Expense, Time Deposits Short-term borrowings Federal Funds Purchased and Securities Sold under Agreements to Repurchase, Total Short-term borrowings Federal Funds Purchased and Securities Sold under Agreements to Repurchase Federal funds purchased and repurchased agreements Other [Member] Accumulated Other [Member] Accumulated other. Total debt securities Gross unrealized losses Investment In Debt Securities Gross Unrealized Losses Investment in debt securities gross unrealized losses. Forward-Starting SOFR-Based Interest Rate Swap Agreements [Member] Forward-Starting SOFR-Based Interest Rate Swap Agreements [Member] Forward-starting SOFR-based interest rate swap agreements. Net change in accrued interest receivable, payable Net Change In Accrued Interest Receivable Payable Net change in accrued interest receivable, payable. Other credit-related commitments Other credit-related commitments Other Credit Related Commitments Other credit-related commitments. Long-term borrowings, fixed interest rate Long-Term Debt, Percentage Bearing Fixed Interest, Percentage Rate Series H Fixed-to-Floating Rate Non-cumulative Perpetual Preferred Stock [Member] Series H Fixed-to-Floating Rate Non-cumulative Perpetual Preferred Stock [Member] Commercial Bank Segment [Member] Commercial Bank [Member] Current Fiscal Year End Date Current Fiscal Year End Date Interest Rate Reduction [Member] Contractual Interest Rate Reduction [Member] Common stock issuable, [11,458] shares at March 31, 2024; 12,217 shares at December 31, 2023 Common Stock Issuable The obligation to issue shares of company common stock in connection with deferred compensation plans. Deferred Income Tax Expense (Benefit), Total Provision for deferred income taxes Deferred Income Tax Expense (Benefit) Tax benefit Income Tax Expense (Benefit), Total Income taxes Income Tax Expense (Benefit) Outside data processing software Outside data processing and software Information Technology and Data Processing Bayview Lending Group and Bayview Financial [Member] Bayview Lending Group And Bayview Financial [Member] Bayview Lending Group and Bayview Financial. FHLB advances, non current Long-Term Federal Home Loan Bank Advances, Noncurrent Interest and Fee Income, Loans and Leases, Total Loans and leases, including fees Interest and Fee Income, Loans and Leases Trust Income [Member] Fiduciary and Trust [Member] Loan Restructuring Modification Loan Restructuring Modification [Domain] Disaggregation Of Revenue [Table] Disaggregation of Revenue [Table] Accrued Interest and Other Liabilities [Member] Accrued Interest and Other Liabilities [Member] Accrued interest and other liabilities. Peoples United Financial Inc [Member] Peoples United Financial Inc [Member] Peoples United Financial, Inc. [Member] Series A Series C Series And E Preferred Stock [Member] Series A Series C And Series E Preferred Stock [Member] Series A series C and series E preferred stock. Investment securities in held-to-maturity portfolio securitized by Bayview Financial Debt Security, Mortgage-Backed, Held-to-Maturity, Fair Value Disclosure Unsecured senior notes Unsecured Debt, Current Investment Securities Continuous Unrealized Loss Position Twelve Months or Longer Aggregate Losses Investment Securities Continuous Unrealized Loss Position Twelve Months Or Longer Aggregate Losses Amount of accumulated unrealized loss on investments in debt and equity securities that have been in a continuous loss position for twelve months or longer. Maturing at Various Dates Through January 2023 [Member] Maturing at various dates through January 2023 [Member] Maturing at various dates through January 2023 [Member] Finite-Lived Intangible Assets, Net, Ending Balance Finite-Lived Intangible Assets, Net, Beginning Balance Finite-Lived Intangible Assets, Net, Total Core deposit and other intangible assets Finite-Lived Intangible Assets, Net Information about Company's Segments Schedule of Segment Reporting Information, by Segment [Table Text Block] Deferred Revenue, Total Deferred revenue Deferred Revenue Valuation Approach and Technique Valuation Approach and Technique [Domain] Revenue from contracts with customers Revenue from Contract with Customer [Text Block] Net (increase) decrease in interest-bearing deposits at banks Proceeds from (Payments for) in Interest-Bearing Deposits in Banks Disposal Group Name [Domain] Due after one year through five years Debt Securities, Held-to-Maturity, Fair Value, Maturity, Allocated and Single Maturity Date, after Year One Through Five Other comprehensive income (loss), net of tax and reclassification adjustments: Other Comprehensive Income (Loss), Net of Tax [Abstract] Due after one year through five years Debt Securities, Held-to-Maturity, Amortized Cost, after Allowance for Credit Loss, Maturity, Allocated and Single Maturity Date, after Year One through Five Conventional purchase amount of loan Mortgage loans on real estate principal amount of loans Mortgage loans on real estate principal amount of loans. Hedging Relationship Hedging Relationship [Domain] Mortgage Banking Revenues [Member] Mortgage Banking [Member] Carrying Amount [Member] Measurement Basis [Axis] Financing Receivable, Allowance for Credit Losses [Line Items] Financing Receivable, Allowance for Credit Loss [Line Items] Foreign Exchange and Other Option and Futures Contracts [Member] Foreign Exchange And Other Option And Futures Contracts [Member] Foreign exchange and other option and futures contracts. Commercial Loans and Leases [Member] Commercial Loans And Leases [Member] Commercial loans and leases. Long-Term Debt, Type [Domain] Debt securities held to maturity: Debt Securities, Held-to-Maturity, Amortized Cost, after Allowance for Credit Loss, Maturity [Abstract] Amortized Cost without Allowance Total Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance Term Loans 2023 [Member] Long Term Debt Two Thousand Twenty Three [Member] Long term debt two thousand twenty three. Net yield adjustment from cash flow hedges currently in effect, tax Other Comprehensive Income Loss Net Yield Adjustment From Cash Flow Hedges Tax Other comprehensive income loss net yield adjustment from cash flow hedges, tax. Relationship with BLG and Bayview Financial Relationship With Other Entities [Text Block] Relationship with other entities. Loan delinquent period Loan Delinquent Period For Non Accrual Status Classification The threshold number of days in delinquency at which criticized loans are generally classified as non-accrual. Derivative Instruments Gain Loss By Hedging Relationship By Income Statement Location By Derivative Instrument Risk [Table] Derivative Instruments, Gain (Loss) [Table] Fixed Rate Long-Term Borrowings [Member] Fixed Rate Long Term Borrowings [Member] Fixed rate long-term borrowings. Commitments and Contingencies Disclosure [Abstract] M&T Bank Corporation [Member] M And T [Member] M&T. M&T [Member] Commercial Real Estate Loans [Member] Real Estate Loan [Member] Intersegment Activity Eliminated in Consolidated Totals [Member] Intersegment Eliminations [Member] Shareholders' Equity Equity [Text Block] FRB of New York. FRB of New York [Member] Gross unrealized losses for held to maturity Debt Securities, Held-to-Maturity, Accumulated Unrecognized Loss Change in Cash Flow Hedges Derivative Instruments At Fair Value Net Change in Cash Flow Hedges Derivative Instruments At Fair Value Net Interest paid during the period Interest Paid, Excluding Capitalized Interest, Operating Activities Combination of Modification Types [Member] Combination of Modification Types [Member] Combination of modification types. Series E fixed to floating rate non cumulative perpetual preferred stock. Series E Fixed To Floating Rate Non Cumulative Perpetual Preferred Stock [Member] Series E Fixed-To-Floating Rate Non-Cumulative Perpetual Preferred Stock [Member] Readily marketable securities Gross unrealized gains Readily Marketable Securities At Fair Value Gross Unrealized Gains Readily marketable securities at fair value gross unrealized gains. Current [Member] Financial Asset, Not Past Due [Member] Retirement Plan Type Retirement Plan Type [Domain] Additional Paid in Capital, Total Additional paid-in capital Additional Paid in Capital Liabilities Liabilities [Abstract] Due after ten years Debt Securities, Held-to-Maturity, Fair Value, Maturity, Allocated and Single Maturity Date, after Year 10 Investment securities available for sale, gross unrealized gains Debt Securities, Available-for-Sale, Accumulated Gross Unrealized Gain, before Tax Derivative [Line Items] Derivative [Line Items] Extinguishment of Debt Extinguishment of Debt [Axis] Shareholders' equity Equity, Attributable to Parent [Abstract] Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] 5.75% Fixed Rate Subordinated Notes Due To Mature In October 2024 [Member] Five Point Seven Five Percentage fixed-rate subordinated notes due to mature in October 2024 [Member] 5.75% fixed-rate subordinated notes due to mature in October 2024. Interest cost on projected benefit obligation Defined Benefit Plan, Interest Cost Entity [Domain] Term Loans 2019 [Member] Term Loans 2019 [Member] Long Term Debt Two Thousand Nineteen [Member] Long term debt two thousand nineteen. Trust Relationship [Member] Trust Relationship [Member] Other Postretirement Benefits [Member] Other Postretirement Benefits Plan [Member] Maximum borrowing capacity Line of Credit Facility, Maximum Borrowing Capacity Debt securities held to maturity: Debt Securities, Held-to-Maturity, Fair Value, Maturity [Abstract] Readily marketable securities Estimated fair value Readily Marketable Securities At Estimated Fair Value Readily marketable securities at estimated fair value. Schedule Of Amortized Cost And Estimated Fair Value Of Investment Securities [Table] Schedule Of Amortized Cost And Estimated Fair Value Of Investment Securities [Table] Schedule of amortized cost and estimated fair value of investment securities. Net income per common share Earnings Per Share [Abstract] Due after five years through ten years Debt Securities, Available-for-Sale, Fair Value, Maturity, Allocated and Single Maturity Date, after Year 5 Through 10 Net unrealized gains (losses) on investment securities OCI, Debt Securities, Available-for-Sale, Gain (Loss), after Adjustment and Tax, Total Net unrealized gains (losses) on investment securities OCI, Debt Securities, Available-for-Sale, Gain (Loss), after Adjustment and Tax Financing Receivable, Allowance for Credit Loss, Writeoff, Total Charge-offs Financing Receivable, Allowance for Credit Loss, Writeoff Loss Contingencies [Table] Loss Contingencies [Table] Debt, Weighted Average Interest Rate Weighted average interest rate Loans and leases average rate Investment, Name Investment, Name [Domain] Debt Maturity, Start Year Debt Instrument, Maturity Date Range, Start Accounting Policies [Abstract] Segments Segments [Domain] Federal tax credits and other federal tax benefits recognized Affordable Housing Tax Credits and Other Tax Benefits, Amount Amortization of actuarial losses, before tax Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), Reclassification Adjustment from AOCI, before Tax Total other comprehensive income (loss) before reclassifications, net of tax Other Comprehensive Income (Loss), before Reclassifications, Net of Tax Measurement Input [Extensible List] Debt Instrument, Measurement Input [Extensible Enumeration] Interest Income [Member] Interest Income [Member] Subordinated notes non current Subordinated Long-Term Debt, Noncurrent Impact of estimated fair value gain (losses) on hedging instruments Impact In Estimated Fair Value Gain Losses On Hedging Instruments Impact in estimated fair value gain (losses ) on hedging instruments. Summary of Acquisition, Pro Forma Information Business Acquisition, Pro Forma Information [Table Text Block] Revolving Loans [Member] Revolving Credit Facility [Member] Losses realized in net income, tax Other Comprehensive Income Loss Reclassification Adjustment For Realized Gains Losses Included In Net Income Tax Other comprehensive income loss reclassification adjustment for realized gains losses included in net income tax. Oceanview Dispositions, LLC [Member] Oceanview Dispositions, LLC [Member] Oceanview Dispositions, LLC. Earnings Per Share, Basic, Total Basic earnings per common share Basic Earnings Per Share, Basic Summary of Investment Holdings [Table] Accumulated Other Comprehensive Income (Loss), Net Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block] Debt Securities, Held-to-Maturity, Allowance for Credit Loss, Ending Balance Debt Securities, Held-to-Maturity, Allowance for Credit Loss, Beginning Balance Debt Securities, Held-to-Maturity, Allowance for Credit Loss, Total Allowance for credit losses Debt Securities, Held-to-Maturity, Allowance for Credit Loss Fair value of additional collateral to be posted for derivative financial instruments Additional Collateral, Aggregate Fair Value Business Combinations [Abstract] Income Statement [Abstract] Financing Receivable, Impaired [Line Items] Financing Receivable, Impaired [Line Items] Investment securities Total investment securities Investments Amortization of net actuarial gain Defined Benefit Plan, Amortization of Gain (Loss) Retirement Benefits [Abstract] Statistical Measurement Statistical Measurement [Domain] Loss Contingencies [Line Items] Loss Contingencies [Line Items] Net cash provided by operating activities Net Cash Provided by (Used in) Operating Activities Amortized Cost and Estimated Fair Value of Investment Securities Amortized Cost And Estimated Fair Value Of Investment Securities Table [Text Block] Amortized cost and estimated fair value of investment securities. Interest income Interest and Dividend Income, Operating [Abstract] FHLBs Facility [Member] Federal Home Loan Bank Advances [Member] Asset Derivatives, Fair Value Derivative Asset, Subject to Master Netting Arrangement, before Offset Due after five years through ten years Debt Securities, Available-for-Sale, Amortized Cost, Maturity, Allocated and Single Maturity Date, after Year 5 Through 10 Document Period End Date Document Period End Date Statistical Measurement Statistical Measurement [Axis] Other Commercial Construction [Member] Other Commercial Construction [Member] Other commercial construction. Commitments and contingencies Commitments and Contingencies Disclosure [Text Block] Accounts, Notes, Loans and Financing Receivable [Line Items] Accounts, Notes, Loans and Financing Receivable [Line Items] Earnings Per Share, Diluted, Total Diluted earnings per common share Diluted Earnings Per Share, Diluted Debt Maturity, End Year Debt Instrument, Maturity Date Range, End Product and Service Product and Service [Domain] Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Tax, Total Foreign currency translation adjustment, tax Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Tax Current Delinquency Status of Loans and Leases Receivable Modified Not Past Due Delinquency status of loans and leases receivable modified not past due. Revenue from Contract with Customer [Abstract] Debt Instrument, Name [Domain] Fair Value Hierarchy and NAV Fair Value Hierarchy and NAV [Domain] Commitment expirations Percentage Of Fair Value Inputs Commitment Expirations Percentage of assumed commitment expirations used in the fair value measurements of interest rate locks. Debt securities available for sale: Debt Securities, Available-for-Sale, Fair Value, Fiscal Year Maturity [Abstract] New Market Investments [Member] New Market Investments [Member] New market investments. Bayview Lending Group [Member] Bayview Lending Group [Member] Bayview Lending Group. Real estate acquired in settlement of loans Real Estate Owned, Transfer to Real Estate Owned Maturity Period 2025 [Member] Maturity Period Two [Member] Maturity Period Two [Member]. Settlements Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements Fair Value Measurements, Recurring [Member] Fair Value, Recurring [Member] Defined Benefit Plans [Member] Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member] Foreign currency translation adjustment, before tax Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Gain (Loss), before Reclassification and Tax Estimate assessed losses Loss Contingency, Loss in Period Changes in Cash Flow Hedges Derivative Instruments At Fair Value Net Changes in Cash Flow Hedges Derivative Instruments At Fair Value Net Changes in cash flow hedges derivative instruments at fair value net. Net increase (decrease) in cash, cash equivalents and restricted cash Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents, Period Increase (Decrease), Excluding Exchange Rate Effect Pension Benefits [Member] Pension Plan [Member] Combination of Concession Types [Member] Combination Of Concession Types [Member] Combination of concession types. Total other income Noninterest Income Schedule Of Borrowings [Table] Schedule Of Borrowings [Table] Schedule of borrowings. Business Banking [Member] Business Banking [Member] Business banking segment. Net interest income after provision for credit losses Interest Income (Expense), after Provision for Loan Loss Retail Bank [Member] Retail Bank. Equity Securities, FV-NI, Current Equity Securities, FV-NI, Current Mortgage-backed securities Debt Securities, Available-for-Sale, Maturity, without Single Maturity Date, Amortized Cost Maximum credit risk for recourse associated with loans sold under Federal National Mortgage Association Delegated Underwriting and Servicing program Maximum Credit Risk For Recourse Associated With Loans Sold Under Federal National Mortgage Association Delegated Underwriting And Servicing Program Maximum credit risk for recourse associated with loans sold under Federal National Mortgage Association Delegated Underwriting and Servicing program. Purchases of treasury stock Purchases of treasury stock Payments for Repurchase of Common Stock Discounted Cash Flows Discounted Cash Flows [Member] Discounted cash flows. Finite-Lived Intangible Assets, Major Class Name [Domain] Amount of future funding commitments included in carrying amount Unfunded commitments includes carrrying amount of its investments Unfunded Commitments Includes Carrrying Amount Of Its Investments Unfunded commitments includes carrrying amount of its investments. Real estate loans held for sale Loan, Held-for-Sale, Fair Value Disclosure Total investment securities, fair value less than 12 months Investment Securities Continuous Unrealized Loss Position Less Than Twelve Months Fair Value This item represents the fair value of securities that have been in a continuous loss position for less than twelve months. Due in one year or less Debt Securities, Available-for-Sale, Fair Value, Maturity, Allocated and Single Maturity Date, Year One Other Debt Securities [Member] Other Debt Obligations [Member] Common stock issued Stock Issued During Period, Value, Acquisitions Entity Address, Postal Zip Code Entity Address, Postal Zip Code Held To Maturity Securities Continuous Unrealized Loss Position12 Months Or Longer Aggregate Losses Debt Securities, Held-to-Maturity, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss Entity Interactive Data Current Entity Interactive Data Current 3.65% Unsecured Senior Notes Mature in December 2022 [Member] Three Point Six Five Percentage Unsecured Senior Notes Due To Mature In December 2022 [Member] Three point six five percentage unsecured senior notes due to mature in December 2022. Subordinated Debt, Total Subordinated Debt, Beginning Balance Subordinated Debt, Ending Balance Subordinated Debt Subordinated notes Acquisition of bank and bank holding company, Common stock issued Stock Issued Preferred Stock, Dividend Rate, Percentage Term Loans Prior Period [Member] Long Term Debt Prior Period [Member] Long term debt prior period. Residential Mortgage Loans [Member] Residential Mortgage [Member] Criticized Accrual [Member] Criticized Accrual [Member] Criticized accrual. Credit Facility Credit Facility [Domain] Obligations of States and Political Subdivisions [Member] US States and Political Subdivisions Debt Securities [Member] Text Block [Abstract] Equity [Abstract] Components of Other Comprehensive Income (Loss) and Amounts Reclassified from Accumulated Other Comprehensive Income (Loss) to Net Income Components Of Other Comprehensive Income Loss Table [Text Block] The tabular disclosure of components of other comprehensive income loss. Pass [Member] Pass [Member] Revision of Prior Period Revision of Prior Period [Axis] Total debt securities Estimated fair value Investment In Debt Securities Estimated Fair Value Investment in debt securities estimated fair value. Renewable Energy Investments [Member] Investments In Partnerships [Member] Investments in partnerships. Consumer [Member] Consumer Portfolio Segment [Member] Mortgage-backed securities Debt Securities, Held-to-Maturity, Maturity, without Single Maturity Date, Fair Value Entity Incorporation, State or Country Code Entity Incorporation, State or Country Code Derivative Instruments, Gain (Loss) [Line Items] Derivative Instruments, Gain (Loss) [Line Items] Due after ten years Debt Securities, Available-for-Sale, Fair Value, Maturity, Allocated and Single Maturity Date, after Year 10 Short-term borrowings, fixed interest rate Short-Term Debt, Percentage Bearing Fixed Interest Rate Derivatives, Fair Value [Line Items] Derivatives, Fair Value [Line Items] Equity Components Equity Components [Axis] The date at which the preferred stock dividend rate or the frequency of dividend payments, or both, will change. Preferred Stock Dividend Rate Modifications Date Of Change Date of change in the dividend rate Investments, Debt and Equity Securities [Abstract] All Other [Member] Other Segments [Member] LIBOR [Member] LIBOR [Member] LIBOR. Pension plans and other postretirement benefits Retirement Benefits [Text Block] Commercial Loans [Member] Commercial loans. Less: Preferred stock dividends Preferred Stock Dividends, Income Statement Impact Amount of initial margin posted Collateral Already Posted, Aggregate Fair Value Other securities, Gross unrealized losses Other Securities Gross Unrealized Losses Other securities gross unrealized losses. Other income Noninterest Income [Abstract] Schedule Of Equity Method Investments [Table] Schedule of Equity Method Investments [Table] 30-89 Days Past Due Loans And Leases Receivable Thirty To Eighty Nine Days Past Due Financing receivables that are thirty to eighty nine days past due. Recent accounting developments Accounting Standards Update and Change in Accounting Principle [Text Block] Cost method equity securities Equity Securities, FV-NI, Cost Series G fixed rate reset non-cumulative perpetual preferred stock. Series G Fixed Rate Reset Non Cumulative Perpetual Preferred Stock [Member] Series G Fixed-Rate Reset Non-Cumulative Perpetual Preferred Stock [Member] Other Real Estate, Foreclosed Assets, and Repossessed Assets, Total Amount of foreclosed residential real estate property held Other Real Estate, Foreclosed Assets, and Repossessed Assets Financing Receivable Portfolio Segment Financing Receivable Portfolio Segment [Axis] Revenues from sub-servicing Revenues From Subservicing Revenues from sub-servicing Local Phone Number Local Phone Number Derivatives Designated and Qualifying as Hedging Instruments [Member] Designated as Hedging Instrument [Member] Schedule of Equity Method Investments [Line Items] Schedule of Equity Method Investments [Line Items] Goodwill, Ending balance Goodwill, Beginning balance Goodwill Goodwill Goodwill Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Table] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table] Schedule Of Financing Receivable Allowance For Credit Losses [Table] Financing Receivable, Allowance for Credit Loss [Table] Statement of Cash Flows [Abstract] Unrealized net loss recognized in other comprehensive income related to cash flow hedges Unrealized Gain (Loss) on Interest Rate Cash Flow Hedges, Pretax, Accumulated Other Comprehensive Income (Loss) Unrealized Gain (Loss) on Interest Rate Cash Flow Hedges, Pretax, Accumulated Other Comprehensive Income (Loss) Assets Backed Notes Weighred Average Estimated Life Asset backed notes weighred average estimated life Asset-backed notes weighed average estimated life Hospitality [Member] Hospitality [Member] Hospitality [Member] Variable interest entities and asset securitizations Variable Interest Entities And Asset Securitizations [Text Block] Variable interest entities and asset securitizations. Servicing Asset at Amortized Cost, Ending Balance Servicing Asset at Amortized Cost, Beginning Balance Capitalized servicing rights Servicing Asset at Amortized Cost Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis] Preferred Stock, Dividends Per Share, Declared Accumulated Other Comprehensive Income (Loss), Net of Tax, Total Accumulated other comprehensive income (loss), net Beginning balance, net of tax Ending balance, net of tax Accumulated Other Comprehensive Income (Loss), Net of Tax Segment Reporting Information [Line Items] Segment Reporting Information [Line Items] Unrealized losses on cash flow hedges Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification and Tax Debt Security Category Debt Security Category [Axis] Common stock, par value Common Stock, Par or Stated Value Per Share Income available to common shareholders: Net income available to common shareholders Net Income (Loss) Available to Common Stockholders, Basic [Abstract] 6.082% Fixed Rate Senior Notes Due To Mature In March 2032 [Member] Six Point Zero Eight Two Percentage Fixed Rate Senior Notes Due To Mature In March 2032 [Member] Six point zero eight two percentage fixed rate senior notes due to mature in march 2032. Debt Instrument, Interest Rate, Stated Percentage Interest rate of debt instrument Commercial Real Estate [Member] Commercial Real Estate Segment [Member] Commercial real estate segment. Maximum [Member] Maximum [Member] Due after ten years Debt Securities, Available-for-Sale, Amortized Cost, Maturity, Allocated and Single Maturity Date, after Year 10 Investments in Affordable Housing Projects [Member] Investments in Affordable Housing Projects [Member] Investments in affordable housing projects. Accrued interest payable Accrued interest payable Interest Payable Increase (Decrease) in Loans Held-for-sale, Total Net change in loans originated for sale Increase (Decrease) in Loan, Held-for-Sale Consolidation Items Consolidation Items [Domain] Fair Value, Asset, Recurring Basis, Unobservable Input Reconciliation, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration] Series H Preferred Stock [Member] Preferred Series H [Member] Weighted average commitment expirations, percentage Weighted Average Commitment Expirations Weighted average commitment expirations. Significant Unobservable Inputs (Level 3) [Member] Fair Value, Inputs, Level 3 [Member] Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Table] Fair Value, Recurring and Nonrecurring [Table] Noninterest-Bearing Deposit Liabilities, Domestic, Total Noninterest-bearing deposits Noninterest-bearing deposits Noninterest-Bearing Deposit Liabilities, Domestic Conventional mortgage loans SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate, Face Amount of Mortgages Service cost Defined Benefit Plan, Service Cost Gain (loss) on bank investment securities Debt and Equity Securities, Gain (Loss), Total Gains (losses) on equity securities Debt and Equity Securities, Gain (Loss) Gain (loss) on sale of subsidiary after-tax effect Gain Loss On Sale Of Properties After Tax Gain loss on sale of properties after tax Other Other Interest and Dividend Income Other, net Payments for (Proceeds from) Other Investing Activities Principal Deferral [Member] Payment Deferral [Member] Payment Deferral [Member] Total Delinquency Status of Loans and Leases Receivable Modified Delinquency status of loans and leases receivable modified. Internal Credit Assessment Internal Credit Assessment [Domain] Plus: Incremental shares from assumed conversion of stock-based compensation awards Incremental Common Shares Attributable to Dilutive Effect of Share-Based Payment Arrangements Impact Of Changes [Member] Revision of Prior Period, Change in Accounting Principle, Adjustment [Member] Investment Securities in Continuous Unrealized Loss Position Investment Securities In Continuous Unrealized Loss Position Table [Text Block] Investment securities in continuous unrealized loss position. Operating Segments [Member] Operating Segments [Member] Carrying value of investment securities pledged related to repurchase transactions.. Carrying Value of Investment Securities Pledged Related to Repurchase Transactions Carrying value of investment securities pledged related to repurchase transactions Other expense Noninterest Expense [Abstract] Segment information Segment Reporting Disclosure [Text Block] Carrying Amounts and Estimated Fair Value for Certain Financial Instruments Fair Value, by Balance Sheet Grouping [Table Text Block] City Area Code City Area Code Cash flows from operating activities Net Cash Provided by (Used in) Operating Activities [Abstract] Total other comprehensive income (loss), before tax Other Comprehensive Income (Loss), before Tax Allowance on acquired PCD loans Allowance On Acquired Purchased Credit Deteriorated Loans Allowance on acquired purchased credit deteriorated loans. Investment securities Investments in Debt and Marketable Equity Securities (and Certain Trading Assets) Disclosure [Text Block] Intersegment Activity Eliminated in Consolidated Totals [Member] Consolidation Items [Axis] Asset-Backed Securities, at Carrying Value Asset-backed notes Document Information [Line Items] Document Information [Line Items] Proceeds from Issuance of Long-Term Debt, Total Proceeds from Issuance of Long-Term Debt Proceeds from long-term borrowings Weighted-Average Rate, Variable Derivative, Average Variable Interest Rate Other Consumer Loans [Member] Other Consumer Loans [Member] Other consumer loans. Business Acquisition [Line Items] Business Acquisition [Line Items] Reduction in estimated fair value of interest rate contracts in liability position Increase Decrease In Estimated Fair Value Of Interest Rate Contracts In Liability Position Increase (decrease) in estimated fair value of interest rate contracts in liability position. Mortgage-backed securities Debt Securities, Available-for-Sale, Maturity, without Single Maturity Date, Fair Value Pledging Purpose [Domain] Weighted-average shares outstanding: Weighted Average Number of Shares Outstanding, Basic [Abstract] Commercial Loans and Commercial Real Estate [Member] Commercial Loans And Commercial Real Estate [Member] Commercial loans and commercial real estate. Common shares outstanding (including common stock issuable) and unvested stock-based compensation awards Common shares outstanding (including common stock issuable) and unvested stock-based compensation awards Common Shares Outstanding Including Common Stock Issuable And Unvested Stock Based Compensation Awards The weighted average number of common shares outstanding (including common stock issuable) and unvested stock-based compensation awards. Losses realized in net income, net of tax Other Comprehensive Income Loss Reclassification Adjustment For Realized Gains Losses Included In Net Income Net Of Tax Other comprehensive income loss reclassification adjustment for realized gains losses included in net income net of tax. Loans Loans and leases, net Loans and Leases Receivable, Net Amount Weighted Average Number of Shares Outstanding, Basic, Total Weighted-average shares outstanding Basic Weighted Average Number of Shares Outstanding, Basic Salaries and employee benefits Labor and Related Expense Cash flows from financing activities Net Cash Provided by (Used in) Financing Activities [Abstract] Loss on securitization of assets Gain (Loss) on Securitization of Financial Assets Gross unrealized gains for held to maturity Debt Securities, Held-to-Maturity, Accumulated Unrecognized Gain Net income available to common equity Net Income Loss Available To Common Stockholders Diluted Before Unvested Stock Based Compensation Awards Adjustment Net income loss available to common stockholders before unvested stock based compensation awards adjustment as used in the determination of diluted earnings per common share. Carrying amount Investments In Variable Interest Entity Carrying Amount The carrying amount of investments in variable interest entity. Amortization of actuarial losses, net of tax Other Comprehensive Income Amortization Of Defined Benefit Plan Actuarial Loss Recognized In Net Periodic Benefit Cost Net Of Tax Other comprehensive income amortization of defined benefit plan actuarial loss recognized in net periodic benefit cost net of tax. Statement [Table] Statement [Table] Derivatives not designated as hedging instruments, Derivatives Gain (Loss) on Derivative Instruments Held for Trading Purposes, Net Total Average Assets Average Asset Average assets. Document Fiscal Period Focus Document Fiscal Period Focus Income (loss) from equity method investments Income (Loss) from Equity Method Investments Five point five five percentage fixed rate senior notes due to mature in August 2028. Five point five five percentage fixed rate senior notes due to mature in August 2028 [Member] 4.55% Fixed Rate Senior Notes Due to Mature in August 2022 [Member] Investment Securities [Member] Securities Investment [Member] Derivatives Not Designated and Qualifying as Hedging Instruments [Member] Not Designated as Hedging Instrument [Member] Savings and interest-checking deposits Interest Expenses Savings And Interest Checking Deposits Interest expenses savings and interest checking deposits. Summary of loans in Accrual and Nonaccrual Status Summary Of Loans In Accrual And Nonaccrual Status Table [Text Block] Summary of loans in accrual and nonaccrual status. Statement [Line Items] Statement [Line Items] Losses realized in net income Other Comprehensive Income Loss Reclassification Adjustment For Realized Gains Losses Included In Net Income Before Tax Other comprehensive income loss reclassification adjustment for realized gains losses included in net income before tax. Retail Banking [Member] Retail Banking [Member] Retail banking segment. Interest Expense, Short-Term Borrowings, Total Short-term borrowings Interest Expense, Short-Term Borrowings Taxable-equivalent adjustment Taxable Equivalent Adjustment Taxable equivalent adjustment. Other Commitments To Extend Credit For Other Commitments to extend credit for other. Estimated Fair Value Gain (Loss) Increase (Decrease) in Fair Value of Interest Rate Fair Value Hedging Instruments Antidilutive securities excluded from computation of earnings per share Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Increase (Decrease) in Deposits, Total Increase (Decrease) in Deposits Net increase (decrease) in deposits Net unrealized pre-tax gains related to hedged loans held for sale, commitments to originate loans for sale and commitments to sell loans Derivative Hedged Loans As of the balance sheet date of the net amount of unrealized pre-tax gains and losses from hedged loans, that are held for sale, commitments to originate loans for sale and commitments to sell loans, and that meet the criteria of being accounted for as derivative instruments. Capitalized servicing rights, valuation allowance Servicing Asset at Amortized Cost, Increase (Decrease) for Valuation Allowance Adjustment Investment Securities Continuous Unrealized Loss Position Less Than Twelve Months Aggregate Losses Investment Securities Continuous Unrealized Loss Position Less Than Twelve Months Aggregate Losses Amount of accumulated unrealized loss on investments in debt and equity securities that have been in a continuous loss position for less than twelve months. Equity and other securities, Amortized Cost Equity and other securities, cost Equity And Other Securities At Cost Equity and other securities at cost. Internal Credit Assessment Internal Credit Assessment [Axis] Standby letters of credit Letters of Credit Outstanding, Amount Fair value of Liabilities assumed Liabilities Assumed Defined Benefit Plan, Net Periodic Benefit Cost (Credit) Excluding Service Cost, Statement of Income or Comprehensive Income [Extensible Enumeration] Asset Class Asset Class [Domain] Loans Insured or Guaranteed by Government Authorities [Domain] Equity and other securities Other securities, Amortized cost Other Investments and Securities, at Cost Derivative Asset, Including Not Subject to Master Netting Arrangement, after Offset and Deduction, Total Net fair value of derivative financial instruments in a net asset position Derivative Asset, Including Not Subject to Master Netting Arrangement, after Offset and Deduction Common Stock [Member] Common Stock [Member] Debt Instrument [Line Items] Derivative Asset, Subject to Master Netting Arrangement, before Offset of Collateral, Total Aggregate fair value of derivative financial instruments in asset position Derivative Asset, Subject to Master Netting Arrangement, before Offset of Collateral Cash and Cash Equivalents, at Carrying Value, Total Cash and cash equivalents Cash and Cash Equivalents, at Carrying Value Changes in Allowance for Credit Losses Financing Receivable, Allowance for Credit Loss [Table Text Block] Stock-based compensation transactions, net Share Based Compensation Expense Net The adjustment to common stock or additional paid in capital for the amount of recognized equity-based compensation during the period. Time Deposits, Total Time deposits Time deposits Time Deposits Loans and Leases Receivable, Fees Earned but Excluded from Yield Fee recognized due to syndicated loan facility Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Income tax credits Tax credits Effective Income Tax Rate Reconciliation, Tax Credit, Investment, Amount Trading Activity, by Type Trading Activity, by Type [Domain] Proceeds from sales of investment securities available for sale Proceeds from Sale of Debt Securities, Available-for-Sale Equity securities, Gross Unrealized Losses Equity Securities Gross Unrealized Losses Equity securities gross unrealized losses. Total available for held to maturity (fair value) Debt Securities, Held-to-Maturity, Maturity, Allocated and Single Maturity Date, Fair Value Maturity Period 2026 [Member] Maturity Period Three [Member] Maturity Period Three [Member]. Revision of Prior Period, Reclassification, Adjustment [Member] Revision of Prior Period, Reclassification, Adjustment [Member] Commercial and industrial Commitments To Extend Credit For Commercial And Industrial Commitments to extend credit for commercial and industrial. Beginning balance, before tax Ending balance, before tax AOCI Including Portion Attributable to Noncontrolling Interest, before Tax ASU 2016-13 [Member] Accounting Standards Update 2016-13 [Member] Service Charges on Deposit Accounts [Member] Deposit Account [Member] Schedule Of Impaired Financing Receivable [Table] Schedule of Impaired Financing Receivable [Table] Interest Income, Domestic Deposits, Total Deposits at banks Interest Income, Domestic Deposits Residential Limited Documentation [Member] Residential Limited Documentation [Member] Residential limited documentation. Schedule of Debt [Table Text Block] Schedule of Borrowings Treasury stock - common, at cost - [12,724,121] shares at March 31, 2024; 13,300,298 shares at December 31, 2023 Treasury Stock, Value, Total Treasury Stock, Value Cover [Abstract] Allowance for credit losses at acquisition Amortized Cost Impaired Financing Receivable, Related Allowance Allowance for credit losses at acquisition Document Fiscal Year Focus Document Fiscal Year Focus Transfers out of Level 3 Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3 Due in one year or less Debt Securities, Held-to-Maturity, Fair Value, Maturity, Allocated and Single Maturity Date, Year One Comprehensive income Comprehensive Income (Loss) Note [Text Block] Derivative Instrument, Gain (Loss) Reclassified from AOCI into Income, Effective Portion, Statement of Income or Comprehensive Income [Extensible Enumeration] Income Taxes Paid, Net, Total Income taxes paid during the period Income Taxes Paid, Net Investment Banking, Legal and Other Services [Member] Financial Service [Member] FHLB of New York. FHLB of New York [Member] Additional borrowing capacity Line of Credit Facility, additional Borrowing Capacity Line of credit facility, additional borrowing capacity. Preferred Stock [Member] Preferred Stock [Member] Contingent commitments Contingent commitments to provide additional capital contributions to partnerships Contingent Commitments to Provide Additional Capital Contributions to Partnerships Contingent Commitments to Provide Additional Capital Contributions to Partnerships Summary of Payment Status of Loans Modified Financing Receivable, Past Due [Table Text Block] Financing Receivable Recorded Investment [Line Items] Financing Receivable, Credit Quality Indicator [Line Items] Other commercial real estate Commitments To Extend Credit For Other Commercial Real Estate Commitments to extend credit for other commercial real estate. Reduction to income tax expense Increase (Decrease) in Income Taxes Historical recovery rate of collateral values of consumer installment loans. Historical Recovery Rate Of Collateral Values Of Consumer Installment Loans Historical recovery rate of collateral values of consumer installment loans Automobile [Member] Automobile Loan [Member] Segment Reporting [Abstract] Commercial [Member] Commercial Real Estate Excluding Residential Builder And Developer And Other Construction [Member] Commercial real estate excluding residential builder and developer and other construction. Security Exchange Name Security Exchange Name Preferred Series I [Member] Series I Preferred Stocks [Member] Series I preferred stocks Total other comprehensive income (loss) before reclassifications, before tax Other Comprehensive Income (Loss), before Reclassifications, before Tax Recent accounting developments New Accounting Pronouncements, Policy [Policy Text Block] Preferred stock, shares issued Preferred Stock, Shares Issued Preferred stock, shares authorized Preferred Stock, Shares Authorized Loans And Leases Receivable [Table] Loans And Leases Receivable [Table] Loans and Leases receivable. Additional subserviced residential mortgage loans of privately held company. Additional SubServiced Residential Mortgage Loans Of Privately Held Company Additional residential mortgage loans from Bayview Financial Liability Derivatives, Fair Value Derivative Liability, Subject to Master Netting Arrangement, before Offset Dividends paid — preferred Payments of Ordinary Dividends, Preferred Stock and Preference Stock Syndicated Loan Facility [Member] Syndicated Loan Facility [Member] Syndicated loan facility. Financial guarantees and indemnification contracts Commitments Regarding Financial Guarantees And Indemnification Contracts Commitments regarding financial guarantees and indemnification contracts. Additions to right-of-use assets under operating leases Right-of-Use Asset Obtained in Exchange for Operating Lease Liability Other assets for its "investment" in the common securities recognized by the company of various trusts Other Assets For Its Investment In Common Securities Recognized By Company Of Various Trusts Other assets for its "investment" in the common securities recognized by the company of various trusts. Commercial Real Estate [Member] Commercial Real Estate Portfolio Segment [Member] Hedging Designation Hedging Designation [Domain] M&T Insurance Agency, Inc. M&T Insurance Agency, Inc [Member] M&T Insurance Agency, Inc [Member] Marketing and Advertising Expense, Total Advertising and marketing Marketing and Advertising Expense Business Acquisition, Acquiree Business Acquisition, Acquiree [Domain] Total other comprehensive income (loss), tax Other Comprehensive Income (Loss), Tax Legal Entity [Axis] Financial Instrument Financial Instrument [Axis] Adjusted weighted-average shares outstanding: Average common shares outstanding Weighted Average Number of Shares Outstanding, Diluted [Abstract] Revolving Loans Converted to Term Loans [Member] Revolving Loans Converted To Term Loans [Member] Revolving loans converted to term loans. Loans And Leases Receivable [Line Items] Loans And Leases Receivable [Line Items] Loans and leases receivable. Junior Subordinated Debenture Owed to Unconsolidated Subsidiary Trust, Total Junior subordinated debentures Junior Subordinated Debenture Owed to Unconsolidated Subsidiary Trust Entity Emerging Growth Company Entity Emerging Growth Company Amendment Flag Amendment Flag Estimated fair value for held to maturity Total Investment securities, held to maturity, fair value Debt Securities, Held-to-Maturity, Fair Value Accruing Loans Past Due 90 Days or More Financing Receivable, 90 Days or More Past Due, Still Accruing Summary of Allocation of Goodwill Business Combination, Segment Allocation [Table Text Block] Other liabilities Other Liabilities, Fair Value Disclosure Acquisition of bank and bank holding company, Common stock awards converted Conversion of Stock, Amount Converted Investment securities available for sale, gross unrealized losses Debt Securities, Available-for-Sale, Accumulated Gross Unrealized Loss, before Tax Accounting Standards Update Accounting Standards Update [Domain] Basis of Accounting Basis of Accounting, Policy [Policy Text Block] Minority interest in Bayview Lending Group LLC Equity Method Investment, Ownership Percentage M&T Bank [Member] M And T Bank [Member] M&T Bank. Loan Modification Activities to Borrowers Experiencing Financial Difficulty on Financing Receivables Modifications to borrowers experiencing financial difficulty on financing receivables [Table Text Block] Modifications to borrowers experiencing financial difficulty on financing receivables. Privately Issued Mortgage-Backed Securities [Member] Privately Issued [Member] Mortgage-Backed Securities, Issued by Private Enterprises [Member] Term Loans 2022 [Member] Long Term Debt Two Thousand Twenty Two [Member] Long term debt two thousand twenty two. Purchases of investment securities Available for sale Payments to Acquire Debt Securities, Available-for-Sale Derivatives in fair value hedging relationships, Derivative Derivative, Gain (Loss) on Derivative, Net Derivative, Gain (Loss) on Derivative, Net, Total Held to maturity, Estimated fair value, 12 months or more Debt Securities, Held-to-Maturity, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value Variable Rate [Domain] Net change in trading account and other non-hedging derivative assets and liabilities Increase (Decrease) in Financial Instruments Used in Operating Activities, Total Increase (Decrease) in Financial Instruments Used in Operating Activities Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net, Total Increase decrease in net interest income due to interest rate swap agreements Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net Government Issued or Guaranteed [Member] Government Issued or Guaranteed [Member] Mortgage-Backed Securities, Issued by US Government Sponsored Enterprises [Member] Entity File Number Securities Act File Number Pledged Status [Domain] Net decrease in loan servicing advances Net Increase Decrease In Loan Servicing Advances The net cash outflow or inflow for the increase (decrease) of loan servicing advances. Other Noninterest Income Expense Other Operating Income Loss Noninterest income (expense), other operating income (loss). Accrued liability Loss Contingency Accrual, Product Liability, Net Loss Contingency Accrual, Product Liability, Net, Total Total debt securities Amortized cost Investment In Debt Securities Amortized Cost Investment in debt securities amortized cost. Other Liabilities, Total Accrued interest and other liabilities Other Liabilities Unrealized holding gains (losses), net of tax OCI, Debt Securities, Available-for-Sale, Unrealized Holding Gain (Loss), before Adjustment, after Tax Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents, Total Cash, cash equivalents and restricted cash at beginning of period Cash, cash equivalents and restricted cash at end of period Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents Maturity Period 2024 [Member] Maturity Period One [Member] Maturity Period One [Member]. Recreational Finance [Member] Recreational Finance [Member] Recreational finance. Cash Flow Hedges Derivative Instruments at Fair Value, Net, Total Cash flow hedges derivative instruments income Cash Flow Hedges Derivative Instruments at Fair Value, Net Amount of real estate loan as reported as accruing or nonaccruing Financing Receivable Recorded Investment Accrual Or Nonaccrual Status Financing receivable recorded investment accrual or nonaccrual status. Common stock cash dividends Dividends, Common Stock, Cash Carrying value of investment securities pledged. Carrying Value Of Investment Securities Pledged Investment securities pledged to secure debt carrying value Pledged financial instruments Financing Receivable, after Allowance for Credit Loss Financing Receivable, after Allowance for Credit Loss, Total Debt Instrument [Axis] Cumulative Amount of Fair Value Hedging Adjustment Increasing (Decreasing) the Carrying Amount [Member] Estimate of Fair Value Measurement [Member] Variable Interest Entity Primary Beneficiary [Member] Variable Interest Entity, Primary Beneficiary [Member] Summary of Current, Past Due and Nonaccrual Loans Loans And Leases Receivable Net Of Deferred Income By Accrual Status Table [Text Block] Loans and leases receivable net of deferred income by accrual status. Affordable Housing Projects [member] Affordable Housing Projects [Member] Affordable housing projects. Proceeds from maturities of investment securities Held to maturity Proceeds from Maturities, Prepayments and Calls of Held-to-Maturity Securities Debt and Equity Securities, Realized Gain (Loss), Total Gross realized gains(loss) on sale of investment securities Debt and Equity Securities, Realized Gain (Loss) Interest Rate Contracts [Member] Interest Rate Contract [Member] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] Debt, Current [Abstract] Short-term borrowings Asset backed securities weighted average estimated life Assets backed notes weighed average estimated life. Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax, Total Defined benefit plans liability adjustments Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax Schedule Of Defined Benefit Plans Disclosures [Table] Schedule of Defined Benefit Plans Disclosures [Table] Preferred stock, $1.00 par, 20,000,000 shares authorized; Issued and outstanding: Liquidation preference of $1,000 per share: 350,000 shares at March 31, 2024 and December 31, 2023; Liquidation preference of $10,000 per share: 140,000 shares at March 31, 2024 and December 31, 2023; Liquidation preference of $25 per share: 10,000,000 shares at March 31, 2024 and December 31, 2023 Carrying Value Preferred Stock, Value, Issued Entity Small Business Entity Small Business Total Total Unpaid principal balance Impaired Financing Receivable, Unpaid Principal Balance Entity Shell Company Entity Shell Company Investment Type Investment Type [Axis] Residential [Member] One-to-Four Family Residential [Member] Residential Portfolio Segment [Member] Commercial and Industrial [Member] Commercial and industrial Portfolio Segment [Member] Commercial and industrial portfolio segment. Commitments to sell real estate loans Commitments To Sell Real Estate Loans Notional Amount Commitments to sell real estate loans notional amount. Schedule Of Available For Sale Securities And Held To Maturity [Table] Schedule Of Available For Sale Securities And Held To Maturity [Table] Schedule of available for sale securities and held to maturity. Fair value of Assets acquired (noncash) Fair Value of Assets Acquired Total loans Financing Receivable, before Allowance for Credit Loss Financing Receivable, before Allowance for Credit Loss, Total Loans pledged to secure outstanding borrowings Estimate assessed losses increase Loss Contingency Accrual, Period Increase (Decrease) Loss Contingency Accrual, Period Increase (Decrease), Total Earnings per common share Earnings Per Share [Text Block] Home Equity Lines and Loans [Member] Home Equity Lines And Loans [Member] Home equity lines and loans. Counterparties [Member] Counterparties [Member] Counterparties. Credit Risk Derivative [Member] Credit Risk Derivative [Member] Credit risk derivative. Entity Address, Address Line One Entity Address, Address Line One Fair Value Hedges [Member] Fair Value Hedging [Member] Net charge-offs Net (charge-offs) recoveries Allowance for Loan and Lease Losses, Writeoff, Net Other assets Other Assets, Fair Value Disclosure Preferred Stock, Redemption Date Commercial Banking [Member] Commercial Banking [Member] Commercial banking segment. Other revenues from operations Noninterest Income, Other Operating Income Subsequent Event Type Subsequent Event Type [Domain] Revenue Total interest income Interest and Dividend Income, Operating Amortization of actuarial losses, tax Other Comprehensive Income Amortization Of Defined Benefit Plan Actuarial Loss Recognized In Net Periodic Benefit Cost Tax Effect Other comprehensive income amortization of defined benefit plan actuarial loss recognized in net periodic benefit cost tax effect. Issued and Outstanding Preferred Stock Schedule of Stock by Class [Table Text Block] Discretionary Portfolio [Member] Discretionary Portfolio [Member] Discretionary portfolio segment. Income Statement Location Income Statement Location [Axis] Unrealized holding gains (losses), net, before tax OCI, Debt Securities, Available-for-Sale, Unrealized Holding Gain (Loss), before Adjustment and Tax Advances from FHLB FHLB advances Federal Home Loan Bank, Advance, Maturity, Year One, Total Federal Home Loan Bank, Advance, Maturity, Year One Past Due 90 Days or More Delinquency Status of Loans and Leases Receivable Modified Past Due Ninety Days or More Delinquency status of loans and leases receivable modified past due ninety days or more. Less: Income attributable to unvested stock-based compensation awards Income Attributable To Unvested Stock Based Compensation Awards Diluted Income attributable to unvested stock based compensation awards. This amount is used as a reduction to net income available to common equity in the calculation of net income available to common shareholders as used in the determination of diluted earnings per share. Commitments to Sell Real Estate Loans [Member] Commitments To Sell Real Estate Loans [Member] Commitments to sell real estate loans. Long-Term Debt, Type [Axis] Fair Value, Measurements, Nonrecurring [Member] Fair Value, Nonrecurring [Member] Schedule of Investments in Partnerships Qualifying for Proportional Amortization Method Schedule of Investments in Partnerships Qualifying For Proportional Amortization Method [Table Text Block] Schedule of investments in partnerships qualifying for proportional amortization method. Significant Observable Inputs (Level 2) [Member] Fair Value, Inputs, Level 2 [Member] Junior Subordinated Notes, Total Junior Subordinated Notes Junior subordinated debentures Class of Financing Receivable Class of Financing Receivable [Axis] Carrying value of minority interest investment in Bayview Lending Group LLC Equity Method Investments Net yield adjustment from cash flow hedges currently in effect, net of tax Other Comprehensive Income Loss Net Yield Adjustment From Cash Flow Hedges Net Of Tax Other comprehensive income loss net yield adjustment from cash flow hedges, net of tax. Equity securities, Gross Unrealized Gains Equity Securities Gross Unrealized Gains Equity securities gross unrealized gains. Product and Service Product and Service [Axis] Purchases of treasury stock Treasury Stock, Value, Acquired, Cost Method Class of Financing Receivable Class of Financing Receivable [Domain] Commercial and Industrial Loans [Member] Commercial and industrial loans. Title of 12(b) Security Title of 12(b) Security Loans and leases, unearned discount Unearned discount Loans and Leases Receivable, Deferred Income Previously Reported [Member] Previously Reported [Member] Equity Securities [Member] Equity Securities [Member] Maximum exposure to loss of investments in real estate partnerships Maximum Exposure To Loss Of Investments In Real Estate Partnerships Maximum exposure to loss of investments in real estate partnerships. Information about Interest Rate Swap Agreements Schedule of Interest Rate Derivatives [Table Text Block] Common Stock Issuable [Member] Common Stock Issuable [Member] Common stock issuable. Amortization of capitalized servicing rights Amortization of Mortgage Servicing Rights (MSRs) Investments Investments [Domain] Number of modifications Financing Receivable, Modifications, Number of Contracts Accounting Standards Update Accounting Standards Update [Axis] Brokerage services income Brokerage Commissions Revenue Trading Activity Trading Activity [Axis] Other [Member] Other Loans [Member] Other loans. Accounting Changes and Error Corrections [Abstract] Preferred stock per share dividend amount Preferred Stock, Dividends, Per Share, Cash Paid Total deposits Deposits Cash flows from investing activities Net Cash Provided by (Used in) Investing Activities [Abstract] Carrying Amount [Member] Reported Value Measurement [Member] Interest Rate Swap Agreements [Member] Interest Rate Swap [Member] Less: Unvested stock-based compensation awards Unvested Stock Based Compensation Awards Number of shares related to unvested stock-based compensation awards. This amount is a reduction in the calculation of weighted average shares outstanding for the earnings per share calculation. Outstanding principal balances of residential mortgage loans from Bayview Financial Sub Serviced Residential Mortgage Loans Of Privately Held Company Outstanding principal balance of sub-serviced residential real estate loans for a privately-held specialty mortgage finance company. Derivative [Table] Derivative [Table] Credit facility drawn Long-Term Line of Credit Long-Term Line of Credit, Total Portion at Fair Value Measurement [Member] [Default] Portion at Fair Value Measurement [Member] Renewable Energy [Member] Renewable Energy [Member] Renewable energy. Percent of total loan class Financing receivable modification percent of total loan class Financing receivable modification percent of total loan class. Core Deposit and Other Intangible Assets [Member] Core Deposit And Other Intangible Assets Member Core deposit and other intangible assets. Residential Builder and Developer [Member] Residential Builder And Developer [Member] Residential builder and developer. Preferred stock, liquidation preference per share Preferred Stock, Liquidation Preference Per Share Nonaccrual Loans and Leases Receivable, Nonperforming, Nonaccrual of Interest Amortized Cost and Estimated Fair Value of Debt Securities by Contractual Maturity Amortized Cost And Estimated Fair Value Of Debt Securities By Contractual Maturity Table [Text Block] Amortized cost and estimated fair value of debt securities by contractual maturity. SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate, Loan Type [Axis] Residential Mortgage-Backed Securities [Member] Residential [Member] Residential Mortgage-Backed Securities [Member] Due after one year through five years Debt Securities, Available-for-Sale, Fair Value, Maturity, Allocated and Single Maturity Date, after Year One Through Five Loans and leases, net of unearned discount of $928 at March 31, 2024 and $868 at December 31, 2023 Loans and leases, net of unearned discount Loans and leases, net of unearned discount Loans and Leases Receivable, Net of Deferred Income Unfunded Commitments to Extend Credit [Member] Unfunded Loan Commitment [Member] Treasury Stock [Member] Treasury Stock Preferred And Common Stock [Member] Treasury stock preferred and common stock. Other than Temporary Impairment, Credit Losses Recognized in Earnings, Categories of Investments Other than Temporary Impairment, Credit Losses Recognized in Earnings, Categories of Investments [Domain] Residential real estate loans to be sold Commitments To Extend Credit For Residential Real Estate Loans To Be Sold Commitments to extend credit for residential real estate loans to be sold. Home Equity Loans and Lines of Credit [Member] Home Equity Line of Credit [Member] Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] Term Loans 2024 [Member] Long Term Debt Two Thousand Twenty Four [Member] Long term debt two thousand twenty four. Clearinghouse Credit Facilities [Member] Clearinghouse Credit Facilities [Member] Clearinghouse credit facilities. Total available for sale (amortized cost) Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Amortized Cost Loans and leases, net of unearned discount Financing Receivable, Modified in Period, Amount Short-term borrowings Short-Term Debt Total short-term borrowings Series I Preferred Stock [Member] Series I Preferred Stock [Member] Outstanding nonredeemable series I preferred stock or outstanding series I preferred stock. Classified within stockholders' equity if nonredeemable or redeemable solely at the option of the issuer. Classified within temporary equity if redemption is outside the control of the issuer. Schedule Of Available For Sale Securities And Held To Maturity [Line Items] Schedule Of Available For Sale Securities And Held To Maturity [Line Items] Schedule of available for sale securities and held to maturity. Summary of Unpaid Principal Balance to Fair Value of Loans and Leases by Portfolio Segment Impaired Financing Receivables [Table Text Block] 4.0% Fixed Rate Subordinated Notes Due Mature in July 2024 [Member] Four Percentage Fixed Rate Subordinated Notes Due to Mature in July 2024 [Member] Four percentage fixed rate subordinated notes due to mature in july 2024. Other Postretirement Benefits [Member] Retirement Plan Type [Axis] Number of basis points, or hundredths of one percent, added to the three month London Interbank Offered Rate to determine the dividend rate on Series E preferred stock after February 14, 2024. London Interbank Offered Rate Plus Basis Points London Interbank offered rate plus basis points Trading account Trading Account Trading account. Income Statement Location Income Statement Location [Domain] Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification and Tax, Total Cash flow hedges adjustments Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification and Tax Merchant discount and credit card interchange fees Merchant discount and credit card interchange fees Merchant discount and credit card interchange fees. Document Type Document Type Amortization of prior service cost Defined Benefit Plan, Amortization of Prior Service Cost (Credit) Percentage of equity interest issued on certificates Percentage of Equity Interest Issued on Certificates Percentage of equity interest issued on certificates. Exempt from federal taxes Interest Income, Securities, Operating, Tax Exempt Financing Receivable Portfolio Segment Financing Receivable Portfolio Segment [Domain] Available line of credit Line of Credit Facility, Current Borrowing Capacity Net cash used by investing activities Net Cash Provided by (Used in) Investing Activities Asset Pledged as Collateral without Right [Member] Document Quarterly Report Document Quarterly Report Series I fixed rate reset non cumulative perpetual preferred stock. Series I Fixed Rate Reset Non Cumulative Perpetual Preferred Stock [Member] Series I Fixed-Rate Reset Non-Cumulative Perpetual Preferred Stock [Member] Schedule Of Borrowings [Line Items] Schedule Of Borrowings [Line Items] Schedule of borrowings. Notional amounts of derivative contracts entered into for trading account purposes Notional Amount Derivative, Notional Amount Net income available to common shareholders Basic Net Income (Loss) Available to Common Stockholders, Basic Quantitative Information Related to Significant Unobservable Inputs Quantitative Information Related To Significant Unobservable Inputs Table [Text Block] Quantitative information related to significant unobservable inputs. Net cash provided by financing activities Net Cash Provided by (Used in) Financing Activities Debt Instrument, Redemption, Period Debt Instrument, Redemption, Period [Domain] Bayview Financial [Member] Bayview Financial [Member] Bayview Financial. Pledged Status [Axis] Entity Filer Category Entity Filer Category Preferred stock redemption period after stock disqualifies as tier I capital. Preferred Stock Redemption Period After Stock Disqualifies As Tier I Capital Preferred Stock, Redemption Feature, Redemption Term Other costs of operations Other Noninterest Expense Supplemental schedule of noncash investing and financing activities Cash Flow, Noncash Investing and Financing Activities Disclosure [Abstract] Due after five years through ten years Debt Securities, Held-to-Maturity, Fair Value, Maturity, Allocated and Single Maturity Date, after Year 5 Through 10 Total debt securities Gross unrealized gains Investment In Debt Securities Gross Unrealized Gains Investment in debt securities gross unrealized gains. Balance Sheet Location Balance Sheet Location [Domain] Fixed Rate Senior Notes Fixed Rate Senior Notes [Member] Fixed rate senior notes. Term Loans 2020 [Member] Term Loans 2020 [Member] Long Term Debt Two Thousand Twenty [Member] Long term debt two thousand twenty. Readily marketable securities Gross unrealized losses Readily Marketable Securities At Fair Value Gross Unrealized Losses Readily marketable securities at fair value gross unrealized losses. Foreign currency translation adjustments, net of tax Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax, Total Foreign currency translation adjustments Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax FDIC assessments Federal Deposit Insurance Corporation Premium Expense Less: Income attributable to unvested stock-based compensation awards Income Attributable To Unvested Stock Based Compensation Awards Basic Income attributable to unvested stock based compensation awards. This amount is used as a reduction to net income available to common equity in the calculation of net income available to common shareholders as used in the determination of basic earnings per common share. Variable Rate [Axis] Due in one year or less Debt Securities, Held-to-Maturity, Amortized Cost, after Allowance for Credit Loss, Maturity, Allocated and Single Maturity Date, Year One Amortized Cost And Fair Value Debt Securities [Abstract] Amortized cost and fair value debt securities. Assets Backed Notes Weighted Average Interest Rate Asset backed notes weighted average interest rate. Asset-backed notes weighted average interest rate U S treasury rate plus additional rate. U S Treasury Rate Plus Additional Rate U S treasury rate plus additional rate Proceeds from sales of investment securities equity and other Proceeds From Sale Of Equity And Other Securities Investments Proceeds from sale of equity and other securities investments. Pension and Other Postretirement Benefits Cost (Reversal of Cost), Total Defined contribution pension and retirement savings plans total expense Pension and Other Postretirement Benefits Cost (Reversal of Cost) Asset Class Asset Class [Axis] Total liabilities Liabilities Average Maturity (in years) Derivative, Average Remaining Maturity Description of variable rate basis Debt Instrument, Description of Variable Rate Basis Accumulated Other Comprehensive Income Loss [Table] Accumulated Other Comprehensive Income (Loss) [Table] Due after five years through ten years Debt Securities, Held-to-Maturity, Amortized Cost, after Allowance for Credit Loss, Maturity, Allocated and Single Maturity Date, after Year 5 through 10 Series H preferred stocks. Series H Preferred Stocks [Member] Recoveries Financing Receivable, Allowance for Credit Loss, Recovery Asset Impairment Charges, Total Asset write-downs Asset Impairment Charges Fair value of Preferred stock converted Convertible Preferred Stock Converted to Other Securities Total shareholders’ equity Beginning balance Ending balance Equity, Attributable to Parent Shareholders' equity Commercial and other Commitments To Extend Credit For Commercial And Other Commitments to extend credit for commercial and other. LIBOR Rate Plus Additional Rate LIBOR rate plus additional rate. Consolidated Entities Consolidated Entities [Axis] Equity and other securities (cost: $1,279 at March 31, 2024; $1,125 at December 31, 2023) Equity and other securities, Estimated Fair Value Equity And Other Securities Estimated Fair Value Equity and other securities estimated fair value. Collective Investment Trust [Member] Collective Investment Trust. Net income Net Income (Loss) Total interest expense Interest Expense Net Unrealized gains(loss) on sale of investment securities Debt and Equity Securities, Unrealized Gain (Loss) Debt and Equity Securities, Unrealized Gain (Loss), Total Investment securities Interest and Dividend Income, Securities, by Taxable Status [Abstract] Net Periodic Defined Benefit Cost for Defined Benefit Plans Schedule of Defined Benefit Plans Disclosures [Table Text Block] Purchases of investment securities Held to maturity Payments to Acquire Held-to-Maturity Securities Statement of Financial Position [Abstract] Credit cards Commitments To Extend Credit For Credit Cards Commitments to extend credit for credit cards. Due after one year through five years Debt Securities, Available-for-Sale, Amortized Cost, Maturity, Allocated and Single Maturity Date, after Year One Through Five Adjusted weighted-average shares outstanding Diluted Weighted Average Number of Shares Outstanding, Diluted Credit Facility Credit Facility [Axis] Gain (Loss) on Disposition of Assets for Financial Service Operations, Total Net gain on sales of assets Gain (Loss) on Disposition of Assets for Financial Service Operations Commercial letters of credit Commitments Regarding Commercial Letters Of Credit Commitments regarding commercial letters of credit. Non-compete [Member] Non-compete. Offsetting [Abstract] Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Period Increase (Decrease), Total Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Period Increase (Decrease) Changes in net unrealized gains (losses) included in earnings related to instruments still held at period end Remaining balance of loans Loans and Leases Receivable, Gross Loans and leases Discounted rate represented weighted-average option-adjusted basis spread point percentage Assumption For Fair Value Of Interests Continued To Be Held By Transferor Servicing Assets Or Liabilities Option Adjusted Basis Spread On Variable Rate Assumption for fair value of interests continued to be held by transferor servicing assets or liabilities option adjusted basis spread on variable rate. Derivative Assets (Liabilities), at Fair Value, Net, Total Hedged Item Derivative Assets (Liabilities), at Fair Value, Net Investment securities available for sale, amortized cost Investment securities, available for sale, amortized cost Debt Securities, Available-for-Sale, Amortized Cost Maturity Period 2027 [Member] Maturity Period Four [Member] Maturity Period Four. Amortization Investments amortized to income tax expense Amortization Method Qualified Affordable Housing Project Investments, Amortization Net periodic benefit Defined Benefit Plan, Net Periodic Benefit Cost (Credit) Institutional Services and Wealth Management [ Member] Institutional Services and Wealth Management [ Member] Preferred stock cash dividends Dividends, Preferred Stock, Cash Variable Rate Senior Notes Variable Rate Senior Notes [Member] Variable Rate Senior Notes [Member] Common stock issuable, shares Common Stock Issuable Share Number of shares of common stock issuable in connection with deferred compensation plans. Loan Restructuring Modification Loan Restructuring Modification [Axis] Investments in affordable housing projects: Investments in Affordable Housing Projects [Abstract] Valuation Approach and Technique Valuation Approach and Technique [Axis] Disaggregation Of Revenue [Line Items] Disaggregation of Revenue [Line Items] Valuation Allowances Recorded Increase (decrease) in valuation allowance Valuation Allowance for Impairment of Recognized Servicing Assets, Additions (Deductions) for Expenses (Recoveries), Total Valuation Allowance for Impairment of Recognized Servicing Assets, Additions (Deductions) for Expenses (Recoveries) Unrealized Losses 12 Months or More Available For Sale Securities Continuous Unrealized Loss Position Twelve Months Or More Aggregate Losses Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss Weighted-average prepayment speed Assumption for Fair Value of Assets or Liabilities that relate to Transferor's Continuing Involvement, Prepayment Speed Home equity lines of credit Commitments To Extend Credit For Home Equity Lines Of Credit Commitments to extend credit for home equity lines of credit. FHLB advances, current Fair Value Disclosures [Abstract] Equipment financing. Equipment Financing [Member] Fair Value Hierarchy and NAV Fair Value Hierarchy and NAV [Axis] Amortization of investments Amortization Of Investments Amortization of investments. Measurement Frequency Measurement Frequency [Domain] Statement of Partners' Capital [Abstract] Hedging Designation Hedging Designation [Axis] Equipment and net occupancy Occupancy, Net Professional and other services Professional and Contract Services Expense Revision of Prior Period Revision of Prior Period [Domain] Discount rates for fair value estimations Measurement Input Adjustments Measurement input adjustments. Other Assets and Other Liabilities [Member] Other Assets And Other Liabilities [Member] Other assets and other liabilities. Business Acquisition Business Acquisition [Axis] Interest Expense, Long-Term Debt, Total Long-term borrowings Interest Expense, Long-Term Debt Allowance for credit losses Beginning balance Ending balance Loans and Leases Receivable, Allowance Amortized cost of modified loans that subsequently defaulted Amortized Cost of Modified Loans that Subsequently Defaulted Amortized cost of modified loans that subsequently defaulted. Other residential real estate Commitments To Extend Credit For Other Residential Real Estate Commitments to extend credit for other residential real estate. Finite-Lived Intangible Assets by Major Class [Axis] Commercial, Financial, Leasing, etc. [Member] Commercial Financial Leasing [Member] Commercial financial leasing. Cash Flow Hedges [Member] Cash Flow Hedging [Member]