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Reclassification of income tax effects to retained earnings, tax Tax Cuts And Jobs Act Of2017 Reclassification From A O C I To Retained Earnings Tax Tax Cuts and Jobs Act of 2017 reclassification from AOCI to retained earnings tax. Weighted-Average Life (In Years), Outstanding, Ending balance Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term Uncollected amounts receivable Revenue, Remaining Performance Obligation, Amount Defined Benefit Plan Disclosure [Line Items] Defined Benefit Plan Disclosure [Line Items] Parent Company Only Financial Information [Table] Parent Company Only Financial Information [Table] Parent Company Only Financial Information [Table] Amount Banking Regulation, Tier 1 Risk-Based Capital, Actual Residential Real Estate Loans [Member] Residential Real Estate Loans Residential Real Estate Loans [Member] Residential real estate loans Member. Commercial real estate loans to be sold Commitments To Extend Credit For Commercial Real Estate Loans To Be Sold Commitments to extend credit for commercial real estate loans to be sold. Information about Fair Values of Derivative Instruments in Consolidated Statement of Income Derivative Instruments, Gain (Loss) [Table Text Block] Equipment Finance Loan [Member] Equipment Finance Loan [Member] Equipment Finance Loan. Cash received from exercise of stock options Employee Service Share Based Compensation Cash Received From Employee Stock Ownership Plan Employee service share based compensation cash received from employee stock ownership plan. Provision for Loan and Lease Losses, Total Provision for credit losses Provision for Loan and Lease Losses Geographical Geographical [Axis] 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] Vesting period Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Period Debt Instruments [Abstract] Available for sale (cost: $10,69] at December 31, 2023 ; $11,193 at December 31, 2022) Investment securities available for sale, estimated fair value Total Debt Securities, Available-for-Sale Other Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Accretable Yield Interest Other Increase Decrease This item represents other changes in the accretable yield due to changes in expected cash flows including changes in interest rates and prepayment assumptions. Unrealized losses on cash flow hedges, net of tax Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification, after Tax Commercial Real Estate Loans [Member] Commercial Real Estate Loans [Member] Commercial real estate loans. Guaranteed Deposit Fund [Member] Guaranteed Deposit Fund [Member] Guaranteed deposit fund. Schedule Of Segment Reporting Information By Segment [Table] Schedule of Segment Reporting Information, by Segment [Table] Business combination consideration transferred common stock issued. Business Combination Consideration Transferred Common Stock Issued Common stock issued (50,325,004 shares) Summary of Required Minimum and Well Capitalized Capital Ratios Schedule Of Minimum Capital Required To Be Well Capitalized Under Banking Regulations Table [Text Block] Schedule of minimum capital required to be well capitalized under banking regulations. Restricted Stock Units (RSUs) [Member] Restricted Stock Units (RSUs) [Member] Investment Grade Bonds [Member] Investment Grade Bonds [Member] Investment grade bonds. Exclusion limit of loans from related party disclosure Loans and Leases Receivable, Related Parties, Description 2025 Finite-Lived Intangible Asset, Expected Amortization, Year Two Dividend payment terms Preferred Stock, Dividend Payment Terms Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] Fair Value, Inputs, Level 1 [Member] Entity Public Float Entity Public Float 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 Short-term Borrowings [Member] Short-Term Debt [Member] Net Increase Decrease In Short Term Borrowings Net increase (decrease) in short term borrowings. Net increase (decrease) in short-term borrowings Percentage loans in the process of foreclosure, serviced by other entities, classified as government guaranteed Percentage Of Loans In The Process Of Foreclosure Serviced By Other Entities Classified As Government Guaranteed Percentage of loans in the process of foreclosure, serviced by other entities, classified as government guaranteed. Other Long-term Debt, Total Other Other Long-Term Debt Available-for-Sale Securities [Member] Available-for-Sale Securities [Member] Weighted Average [Member] Weighted Average [Member] Commercial Lease [Member] Commercial Lease [Member] Commercial lease. Gain loss on sale of properties pre tax. Gain Loss On Sale Of Properties Pre Tax Gain (loss) on sale of subsidiary, pre-tax Institutional Services & Wealth Management [Member] Institutional Services & Wealth Management [Member] Institutional services & wealth management. Fair value measurements Fair Value Disclosures [Text Block] 2027 Derivative Notional Amount To Expire In Year Four Derivative notional amount to expire in year four. Weighted-average grant date fair value Share Based Compensation Arrangement By Share Based Payment Award Stock Issued In Period Weighted Average Grant Date Fair Value Share based compensation arrangement by share based payment award stock issued in period weighted average grant date fair value. Income taxes Income Tax, Policy [Policy Text Block] Interest income Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Accretable Yield Interest Income The amount of interest from acquired loans included in earnings. Included in earnings Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings Accrued Investment Income Receivable, Total Accrued interest receivable Accrued Investment Income Receivable Banking and Thrift [Abstract] Broker-Dealer, Net Capital Requirement, SEC Regulation [Abstract] Weighted-average discount rates for fair value estimations. Weighted-average Discount Rates for Fair Value Estimations Weighted-average discount rates for fair value estimations Amendments and curtailments Other Comprehensive Income (Loss), Defined Benefit Plan, Settlement and Curtailment Gain (Loss), before Tax Fixed Rate Term Loans 4.65% due 2026 [Member] Fixed Rate Term Loans Of Four Point Six Five Senior Notes Due Two Thousand Twenty Six [Member] Fixed rate term loans of four point six five senior notes due two thousand twenty six. Trading account and other non-hedging derivative gains Trading Gain (Loss), Total Trading Gain (Loss) Actual return on plan assets Defined Benefit Plan, Plan Assets, Increase (Decrease) for Actual Return (Loss) Senior notes Senior Notes Senior Notes, Total Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount, Total Unrecognized compensation cost related to non-vested awards Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount Summary of Sources of Noninterest Income that are Subject to Revenue Recognition 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. Concentration Risk Type Concentration Risk Type [Axis] Derivative, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration] Equity Method Investments and Joint Ventures [Abstract] Short-term Debt, Type Short-Term Debt, Type [Axis] Information about Fair Values of Derivative Instruments in Consolidated Balance Sheet Schedule of Derivative Instruments in Statement of Financial Position, Fair Value [Table Text Block] ICFR Auditor Attestation Flag ICFR Auditor Attestation Flag Change in fair value of nonrecurring fair value measured loans for charge-offs and impairment reserves Increase Decrease In Fair Value Of Nonrecurring Fair Value Measured Loans For Charge Offs And Impairment Reserves Increase (decrease) in fair value of nonrecurring fair value measured loans for charge offs and impairment reserve. Interest on loans Deferred Tax Liabilities Interest On Loans Deferred tax liabilities interest on loans. Long-term Borrowings [Member] Long-Term Debt [Member] Schedule Of Business Acquisitions By Acquisition [Table] Schedule of Business Acquisitions, by Acquisition [Table] 2027 Derivative Notional Amount To Expire In Year Six The notional amount of interest rate swap agreements entered into for risk management purposes that mature during the sixth year after the balance sheet date. Leveraged Leases, Net Investment in Leveraged Leases Disclosure, Rental Receivables, Net, Total Lease payments receivable Leveraged Leases, Net Investment in Leveraged Leases Disclosure, Rental Receivables, Net Schedule Of Compliance With Regulatory Capital Requirements Under Banking Regulations [Table] Schedule of Compliance with Regulatory Capital Requirements under Banking Regulations [Table] Net interest income Net interest income Interest Income (Expense), Net Schedule of Recognized Identified Assets Acquired and Liabilities Assumed [Table Text Block] Summary of Identifiable Assets Acquired, Liabilities Assumed and Preferred Stock Exchanged as of Acquisition 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 Stock-based compensation Compensation Related Costs, Policy [Policy Text Block] Federal funds sold Federal Funds Sold Financial liabilities: Financial Instruments, Financial Liabilities, Balance Sheet Groupings [Abstract] Pledging Purpose [Axis] Amortized Cost with 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] Weighted-average interest rate Short Term Debt Weighted Average Interest Rate During Period The weighted average interest of short-term borrowings during the period. 2023 Transactions 2023 Transactions Goodwill, Acquired During Period Loans measured at fair value on nonrecurring basis Loans Receivable, Fair Value Disclosure Defined Benefit Plan, Plan Assets Level 3 Reconciliation, Increase (Decrease) for Purchase, Sale, and Settlement, Total Purchase(Sales) Defined Benefit Plan, Plan Assets Level 3 Reconciliation, Increase (Decrease) for Purchase, Sale, and Settlement 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. Series I and Series G Preferred Stock [Member] Series I And Series G Preferred Stock [Member] Series I and series G preferred stock 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 Equipment and net occupancy. Equipment and net occupancy Common stock per share dividend amount Common Stock, Dividends, Per Share, Cash Paid Financial Asset, Aging Financial Asset, Aging [Domain] Fixed rate term loan five point seven five percentage due in two thousand twenty four. Fixed Rate Term Loan Five Point Seven Five Percentage Due in Two Thousand Twenty Four [Member] Fixed Rate Term Loans 5.75% due 2024 [Member] Schedule Of Stock By Class [Table] 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. Gains on cash flow hedges Deferred Tax Liability Gains On Cash Flow Hedges Deferred tax liability gains on cash flow hedges. Capital conservation buffer ratio effective. Capital Conservation Buffer Ratio Effective Capital conservation buffer ratio effective Expected return on plan assets Defined Benefit Plan, Expected Return (Loss) on Plan Assets International Activities [Line Items] International Activities [Line Items] International Activities [Line Items] 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 Schedule Of Goodwill [Table] Schedule of Goodwill [Table] Class Of Stock [Line Items] Class of Stock [Line Items] Debt Securities, Trading, and Equity Securities, FV-NI, Total Debt Securities, Trading, and Equity Securities, FV-NI Trading account Unrecognized Income Tax Benefits [Member] Unrecognized Income Tax Benefits [Member] Unrecognized income tax benefits. 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] Shares issued in connection with deferred compensation plans Deferred Compensation Arrangement with Individual, Shares Issued 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 Merchant discount and credit card intercharge fees Merchant Discount And Credit Card Intercharge Fees Merchant discount and credit card intercharge fees. Entity Address, State or Province Entity Address, State or Province Derivative financial instruments Derivative Instruments and Hedging Activities Disclosure [Text Block] Other Deferred Tax Assets, Other Deferred Deferred Income Tax Expense (Benefit), Continuing Operations [Abstract] Securities purchased under agreements to resell and securities sold under agreements to repurchase Repurchase and Resale Agreements Policy [Policy Text Block] Issuance of preferred stock Stock Issued During Period, Value, New Issues Stock Options Outstanding, Beginning balance Stock Options Outstanding, Ending balance Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Number Amortization of prior service credit, net of tax Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), Reclassification Adjustment from AOCI, after Tax Government-Guaranteed Loans [Member] Government Guaranteed Loans [Member] government-guaranteed loans. 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 Purchase of residential mortgage loans Payments For Purchase of Residential Mortgage Loans Payments For Purchase of Residential Mortgage Loans Current income tax receivable Due From Subsidiaries Income Tax Receivable Carrying amount as of the balance sheet date of income taxes previously overpaid to tax authorities by subsidiaries. Goodwill and core deposit and other intangible assets Goodwill and Intangible Assets, Policy [Policy Text Block] Banks Investments In Consolidated Banking Subsidiaries Investments in banks and bank holding companies that are consolidated in the financial statements. 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. Stock Purchase Plan [Member] Employee Stock Purchase Plan [Member] Employee stock purchase plan. Debt Instrument, Redemption, Period Debt Instrument, Redemption, Period [Axis] Leverage - Tier 1 capital to average total assets, as defined Banking Regulation, Tier 1 Leverage Capital Ratio, Well Capitalized, Minimum Other [Member] Other Modifications [Member] Other modifications. Common Stock, Shares, Issued, Total Common stock, shares issued Common Stock, Shares, Issued Weighted average grant date fair value of options granted Share Based Compensation Arrangement By Share Based Payment Award Option Grants In Period Weighted Average Grant Date Fair Value Share based compensation arrangement by share based payment award option grants in period weighted average grant date fair value. 2025 Long-Term Debt, Maturity, Year Two Equity Method Investments And Cost Method Investments [Abstract] Equity Method Investments And Cost Method Investments [Abstract] 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. Defined Benefit Plan, Benefit Obligation, Period Increase (Decrease), Total Defined benefit pension plans Defined Benefit Plan, Benefit Obligation, Period Increase (Decrease) Consolidated Entities Consolidated Entities [Domain] Change in plan assets: Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] Other revenues from operations: Other Revenues From Operations [Abstract] Other revenues from operations. Discount Rate Discount rate 2029 through 2033 Defined Benefit Plan, Expected Future Benefit Payment, after Year Five for Next Five Years Debt Instrument [Table] 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] Business Combination Disclosure [Text Block] Acquisition and divestitures Total other comprehensive income (loss) Net gain (loss) during period Other Comprehensive Income (Loss), Net of Tax BSB Capital Trust III - due 2033 [Member] Bsb Capital Trust Three Variable Rate Due Two Zero Three Three [Member] BSB Capital Trust III - due 2033. Reconciliation Of Unrecognized Tax Benefits [Line Items] Reconciliation Of Unrecognized Tax Benefits [Line Items] Reconciliation of unrecognized tax benefits. Accumulated Other Comprehensive Income (Loss) [Line Items] Accumulated Other Comprehensive Income (Loss) [Line Items] Unusual Risk or Uncertainty, Nature Unusual Risk or Uncertainty, Nature [Domain] Unsecured Debt, Total Variable\fixed rates term loan amount Unsecured Debt Annual rate of increase in health care cost assumed for next fiscal year Defined Benefit Plan, Health Care Cost Trend Rate Assumed, Next Fiscal Year Number of debt securities with gross losses. Number Of Debt Securities With Gross Losses Number of debt securities with aggregate gross unrealized losses Series F And Series G Preferred Stock [Member] Series F And Series G Preferred Stock [Member] Series F And Series G Preferred Stock Land Land Entity Address, City or Town Entity Address, City or Town Term Loans 2018 [Member] Long Term Debt Two Thousand Eighteen [Member] Long term debt two thousand eighteen. Proceeds from Previous Acquisition Acquisition, net of cash consideration, Bank and bank holding company Investments in consolidated subsidiaries Investments In Consolidated Subsidiaries [Abstract] Investments in consolidated subsidiaries. Weighted-average discount rate Operating Lease, Weighted Average Discount Rate, Percent Variable Rate Term Loans Due 2023 [Member] Variable Rate Term Loans Due Two Thousand And Twenty Three [Member] Variable rate term loans due two thousand and twenty three. Interest-bearing deposits at banks Interest-Bearing Deposits in Banks and Other Financial Institutions Projected benefit obligation Benefit obligation at beginning of year Benefit obligation at end of year Defined Benefit Plan, Benefit Obligation 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] Repossessed Assets, Total Assets taken in foreclosure of defaulted loans measured at fair value on a nonrecurring basis Repossessed Assets Borrowings Debt Disclosure [Text Block] Summary of Premises and Equipment Property, Plant and Equipment [Table Text Block] Unrealized holding gains (losses), net, tax OCI, Debt Securities, Available-for-Sale, Unrealized Holding Gain (Loss), before Adjustment, Tax Service asset at amortized value, acquired in business combination. Service Asset at Amortized Value Acquired in Business Combination Acquired in business combination Stock Options Outstanding, Expired Stock Options Outstanding, Expired Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Expirations in Period 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. COVID-19 [Member] C O V I D19 [Member] COVID 19. 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. Total securities with disclosed rating, Amortized Cost Securities With Disclosed Rating Amortized Cost Amortized cost of investment securities excluding equities and U.S. government or government agency issued or guaranteed securities. Average total assets Average Assets The average balance of assets during the period calculated as the average of the asset balances as of the end of each day in the period. 2024 Lessee, Operating Lease, Liability, to be Paid, Next Rolling 12 Months Net change in accrued income and expense Increase Decrease In Accrued Income And Expenses Amount of cash inflow (outflow) from the net change of accrued income and expenses. Servicing Asset at Fair Value, Amount, Ending Balance Servicing Asset at Fair Value, Amount, Beginning Balance Fair value of residential loan servicing assets Servicing Asset at Fair Value, Amount Collateralized mortgage obligations, Amortized cost Collateralized Mortgage Obligations Amortized Cost Amortized cost of collateralized mortgage obligations included in mortgage-backed securities. Current year benefit plans gains, before tax Other Comprehensive (Income) Loss, Defined Benefit Plan, before Reclassification Adjustment and Tax, Total Other Comprehensive (Income) Loss, Defined Benefit Plan, before Reclassification Adjustment and Tax Increases as a result of tax positions taken in prior years Unrecognized Tax Benefits, Increase Resulting from Prior Period Tax Positions Defined Benefit Plan, Benefit Obligation, Business Combination Business combinations Additional Paid-in Capital [Member] Additional Paid-in Capital [Member] Components of Income Tax Expense Schedule of Components of Income Tax Expense (Benefit) [Table Text Block] Business Acquisition, Pro Forma Revenue Total revenues 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] Income before income taxes and equity in undistributed income of subsidiaries Income Loss Before Income Taxes And Equity In Undistributed Income Of Subsidiaries Income (loss) before income taxes and equity in undistributed income of subsidiaries. Cash Acquired from Acquisition Acquisition, net of cash consideration Delinquent period of loans resulting in accrued interest being charged against income description Delinquent Period Of Loans Resulting In Accrued Interest Being Charged Against Income Description Delinquent period of loans resulting in accrued Interest being charged against income description. 2028 Derivative notional amount to expire in year five. Derivative Notional Amount To Expire In Year Five 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 Effect of 25 basis point decrease in discount rate on benefit obligation Defined Benefit Plan Increase Of Twenty Five Basis Point Decrease In Discount Rate On Benefit Obligation Defined benefit plan increase of twenty five basis point decrease in discount rate on benefit obligation. Statement of Stockholders' Equity [Abstract] Payments for (Proceeds from) Loans and Leases, Total Net (increase) decrease in loans and leases Payments for (Proceeds from) Loans and Leases Net charge-offs: Financing Receivable Allowance For Credit Losses Net Write Offs [Abstract] Financing receivable allowance for credit losses net write offs. Investment securities Marketable Securities, Policy [Policy Text Block] 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. Revenue from contract with customer Revenue from Contract with Customer, Including Assessed Tax Weighted-Average Rate, Fixed Derivative, Average Fixed Interest Rate Total due from consolidated bank subsidiaries Due From Subsidiaries Total amount of receivables due from an entity that is affiliated with the reporting entity by means of direct or indirect ownership. Long-term borrowings Loan facility carrying amount Long-term borrowings Long-term borrowings Long-Term Debt Percentage of pension plan assets that is not exceeded by investment in security of single Non-US Government of Government agency Percentage Of Pension Plan Assets That Is Not Exceeded By Investment In Security Of Single Non Us Government Or Government Agency Percentage of pension plan assets that is not exceeded by investment in security of single non US government or government agency. Derivative Contract Derivative Contract [Domain] Schedule Of Financing Receivable Troubled Debt Restructurings [Table] Financing Receivable, Modified [Table] Property, Plant and Equipment, Net, Ending Balance Property, Plant and Equipment, Net, Beginning Balance Premises and equipment, net Premises and equipment Property, Plant and Equipment, Net Capitalized servicing rights Deferred Tax Liabilities, Mortgage Servicing Rights Servicing Assets At Fair Value [Table] Schedule of Servicing Assets at Fair Value [Table] Decrease in minimum liability adjustment Other Comprehensive Income Minimum Pension Liability Net Adjustments Before Tax Other comprehensive income minimum pension liability net adjustments before tax. Class of Stock Class of Stock [Domain] Commercial Real Estate [Member] Commercial Real Estate [Member] Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items] Fair Value Measurement Inputs and Valuation Techniques [Line Items] Benefits paid Defined Benefit Plan, Benefit Obligation, Benefits Paid Core Deposit [Member] Core Deposits [Member] Due in one year or less Debt Securities, Available-for-Sale, Amortized Cost, Maturity, Allocated and Single Maturity Date, Year One Secured Debt, Total Secured loan facilities carrying amount Secured Debt Commitments to extend credit to commercial customers Commitments To Extend Credit To Commercial Customers Commitments to extend credit to commercial customers. 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. Statement of Comprehensive Income [Abstract] Loans secured by real estate delinquent period threshold for return to accrual status Loans Secured By Real Estate Delinquent Period Threshold For Return To Accrual Status Maximum delinquent period for nonaccrual status loans secured by real estate to be returned to accrual status. Provident Statutory Trust III - Due 2033 [Member] Provident Trust Three Statutory Rate Due Two Zero Three Three [Member] Provident Trust three statutory rate due two zero three three. Treasury stock, common shares Treasury Stock, Common, Shares Money-market savings Due From Subsidiaries Money Market Savings Interest bearing deposits held in a money market savings account at subsidiary bank. Discount rate Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Discount Rate Provident Trust I - 8.29%, due 2028 [Member] Provident Trust One Fixed Rates Due Two Zero Two Eight [Member] Provident Trust I - 8.29%, due 2028. Entity Central Index Key Entity Central Index Key Other [Member] Other Intangible Assets [Member] Tax bad debt reserve Deferred Tax Asset, Tax Deferred Expense, Reserve and Accrual, Accounts Receivable, Allowance for Credit Loss Plan Name Plan Name [Domain] Not Rated [Member] Not Rated [Member] Not rated. Deferred Bonus Plan [Member] Employee [Member] Employee. 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] Canada [Member] CANADA Loans and leases 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] Business combination, market value Business Combination, Consideration Transferred, Equity Interests Issued and Issuable Preferred Stock, Shares Outstanding, Ending Balance Preferred Stock, Shares Outstanding, Beginning Balance Preferred stock, Shares Outstanding Preferred stock, shares outstanding Preferred Stock, Shares Outstanding Loans and Leases Receivable, Related Parties, Ending Balance Loans and Leases Receivable, Related Parties, Beginning Balance Borrowing by directors and certain officers of M&T and its banking subsidiaries and their associates Loans and Leases Receivable, Related Parties Period of satisfaction of contract with customer Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period Ratio Banking Regulation, Tier 1 Leverage Capital Ratio, Actual Held to maturity (fair value: $14,308 at December 31, 2023; $12,375 at December 31, 2022) 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. Total other expense Other expense Noninterest Expense Summary of Goodwill Assigned to Reportable Segments for Purposes of Testing for Impairment Schedule of Goodwill [Table Text Block] Unearned income Leveraged Leases, Net Investment in Leveraged Leases Disclosure, Deferred Income Other financial instruments: Other Financial Instruments [Abstract] Other financial instruments. Entity Tax Identification Number Entity Tax Identification Number Total available for held to maturity (amortized cost) Held To Maturity Securities Debt Maturities With Single Maturity Date Net Carrying Amount Carrying amount of debt securities accounted for as held-to-maturity, net of adjustments including, but not limited to, accretion, amortization, collection of cash, previous other-than-temporary impairments (OTTI) recognized, and fair value hedge accounting adjustments, that have single maturity date. Income before taxes Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest Income (loss) before taxes Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration] Tier one capital to risk weighted assets. Tier One Capital To Risk Weighted Assets Ratio Defined Benefit Plan, Actuarial Gain (Loss), Immediate Recognition as Component in Net Periodic Benefit (Cost) Credit Defined benefit pension plan, reduction to change in amortization Defined benefit plan upper limit for qualification percentage Defined Benefit Plan Upper Limit For Qualification Percentage Defined benefit plan upper limit for qualification percentage. Amortized Cost and Estimated Fair Value of Collateralized Mortgage Obligations Amortized Cost And Estimated Fair Value Of Collateralized Mortgage Obligations Table [Text Block] Amortized cost and estimated fair value of collateralized mortgage obligations. 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 Number of investment securities that exceeded ten percent of shareholders' equity Number Of Single Investment Securities That Exceeded Ten Percent Of Shareholders Equity Number of single investment securities that exceeded ten percent of shareholders' equity. Qualified benefit pension plans Defined Benefit Plan Contributions By Employer To Qualified Benefit Pension Plans Defined benefit plan contributions by employer to qualified benefit pension plans. 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] Stock-based compensation Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Share-Based Compensation Cost Investment, Name Investment, Name [Axis] Commitments to extend credit Commitments To Extend Credit [Abstract] Commitments to extend credit. Stated maturity Debt Instrument, Term Amount Banking Regulation, Tier 1 Leverage Capital, Actual Total other comprehensive income (loss) before reclassifications, tax Other Comprehensive Income (Loss) before Reclassifications, Tax Accrued interest and other liabilities [Member] Other Liabilities [Member] Net cash provided (used) by investing activities Net Cash Provided by (Used in) Investing Activities, Continuing Operations Restricted Stock [Member] Restricted Stock [Member] Defined Benefit Plan, Net Periodic Benefit (Cost) Credit, Immediate Recognition of Actuarial Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration] Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield, Reclassifications (to) from Nonaccretable Difference, Total Reclassifications from nonaccretable balance Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield, Reclassifications (to) from Nonaccretable Difference Cayman Islands [Member] CAYMAN ISLANDS Business combination recognized identifiable assets acquired and liabilities assumed deposits. Business combination recognized identifiable assets acquired and liabilities assumed deposits Deposits Postretirement and other employee benefits Deferred Tax Assets Tax Deferred Expense Compensation And Benefits Postretirement And Other Employee Benefits Amount of deferred tax asset attributable to taxable temporary differences from deferred expense compensation and benefits postretirement and other employee benefits. Plan Name Plan Name [Axis] 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 CET1 capital requirement ratio Common Equity Tier One Capital Requirement Ratio Common equity tier one capital requirement ratio. Derivative Instrument Derivative Instrument [Axis] Geographical Geographical [Domain] Other Income And Expenses [Line Items] Other income and expenses. Cumulative effect of change in accounting principle ?equity securities Cumulative Effect On Retained Earnings Net Of Tax Cumulative effect on retained earnings net of tax. Total assets Total assets of partnerships in which the company invested Assets Deposits at Cayman Islands office Interest Expense, Foreign Deposits Advances from the FHLB earliest maturity date Federal Home Loan Bank, Advances, General Debt Obligations, Disclosures, Due Date, Earliest MT M T [Member] M&T member Loans held for sale transferred to loans held for investment 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. Right-of-use assets - operating leases Operating Lease, Right-of-Use Asset Equity in undistributed income of subsidiaries Equity in undistributed income of subsidiaries Equity In Undistributed Income Of Subsidiaries Net change in the equity in undistributed income of subsidiaries. Amount Common Equity Tier One Risk Based Capital Common equity tier one risk based capital. Net adjustment to accumulated other comprehensive income Accumulated Other Comprehensive (Income) Loss, Defined Benefit Plan, after Tax Interest expense Interest Expense [Abstract] Redemption of Series A and Series C preferred stock Stock Redeemed or Called During Period, Value 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] Deferred tax assets unrealized losses investment securities. Deferred Tax Assets Unrealized Losses Investment Securities Unrealized losses Debt Securities, Unrealized Gain (Loss), Total Debt Securities, Unrealized Gain (Loss) Unrealized losses on individual debt securities Adoption of new accounting standard Prior Period Reclassification Adjustment Related Party Related Party, Type [Domain] Retained Earnings (Accumulated Deficit), Ending Balance Retained Earnings (Accumulated Deficit), Beginning Balance Retained Earnings (Accumulated Deficit), Total Retained earnings Retained Earnings (Accumulated Deficit) 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] Residential [Member] Residential Real Estate Excluding Alt A [Member] Residential real estate excluding Alt-A. Recognized income tax benefits related to stock-based compensation Share-Based Payment Arrangement, Expense, Tax Benefit Retained Earnings [Member] Retained Earnings [Member] Income (Loss) from Subsidiaries, Net of Tax, Total Net income of subsidiaries Income (Loss) from Subsidiaries, Net of Tax Total capital to RWA, Minimum Ratio Banking Regulation, Total Risk-Based Capital Ratio, Actual Class of Stock Class of Stock [Axis] Restricted Stock Outstanding, Unvested, Beginning balance Restricted Stock Outstanding, Unvested, Ending balance Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Nonvested, Number Revenues from international trust-related services Revenues From International Trust Related Services Amount of revenues related to international trust related services, including wealth management services, offered internationally. Income taxes at statutory federal income tax rate Effective Income Tax Rate Reconciliation at Federal Statutory Income Tax Rate, Amount Unrealized losses on cash flow hedges, tax Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification, Tax Minimum [Member] Minimum [Member] Impact on fair value of 10% adverse change Sensitivity Analysis of Fair Value, Transferor's Interests in Transferred Financial Assets, Impact of 10 Percent Adverse Change in Prepayment Speed Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items] Financing receivable, modifications other than troubled debt restructuring. Total income Revenues Revenues Regulatory matters Regulatory Capital Requirements under Banking Regulations [Text Block] M&T Bank [Member] Parent [Member] Cash realized from exercise of stock options Proceeds from Stock Options Exercised Significant accounting policies Significant Accounting Policies [Text Block] Derivative Instruments and Hedging Activities Disclosure [Abstract] Commercial Mortgage-Backed Securities [Member] Commercial [Member] Operating Lease, Liability, Total Operating lease liabilities Operating Lease, Liability Derivative Liability, Fair Value, Amount Not Offset Against Collateral, Total Aggregate fair value of derivative financial instruments in a liability position Derivative Liability, Subject to Master Netting Arrangement, before Offset of Collateral Leasehold improvements Leasehold Improvements, Gross Residential Mortgage Banking [Member] Residential Mortgage Banking [Member] Residential mortgage banking segment. Data Relating to Funding Position of Defined Benefit Plans Schedule of Net Funded Status [Table Text Block] Fixed Rate Term Loans Of Five Point Four Zero Senior Notes Due Two Thousand Twenty Five [Member] Fixed Rate Term Loans 5.40% due 2025 [Member] Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Table] Fair Value Measurement Inputs and Valuation Techniques [Table] Government Agency [Member] US Government Agencies Debt Securities [Member] Equity Component Equity Component [Domain] Summary of changes in Accretable Yield for acquired loans Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield Movement Schedule [Roll Forward] Defined contribution pension plan expense Qualified defined contribution plans expense during the period Defined Contribution Plan, Cost Segments Segments [Axis] Stock Option Awards [Member] Credit-related fee income Credit Related Fee Income Credit related fee income. Range of reasonably possible losses Loss Contingency, Estimate of Possible Loss Employer contribution Employer contributions Defined Benefit Plan, Plan Assets, Contributions by Employer Receivables [Abstract] Series F Fixed-to-Floating Rate Non-Cumulative Perpetual Preferred Stock [Member] Series F Fixed To Floating Rate Non Cumulative Perpetual Preferred Stock [Member] Series F fixed-to-floating rate non-cumulative perpetual preferred stock. Percent of maximum revenue from single customer on total revenues Percent Of Maximum Revenue From Single Customer On Revenue Maximum percentage of total consolidated revenues generated from a single external customer. Interest received during the year 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 2025 Defined Benefit Plan, Expected Future Benefit Payment, Year Two 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. 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] Impact on fair value of 10% adverse change Sensitivity Analysis of Fair Value, Transferor's Interests in Transferred Financial Assets, Impact of 10 Percent Adverse Change in Discount Rate Debt Disclosure [Abstract] Gain on divestiture Gain (Loss) on Disposition of Business Net income available to common shareholders Diluted Net Income (Loss) Available to Common Stockholders, Diluted Loans Insured or Guaranteed by Government Authorities [Axis] Business combination recognized identifiable assets acquisition of core deposits and other intangible assets. Business combination recognized identifiable assets acquisition of core deposits and other intangible assets Core deposit and other intangible assets Marketable Securities [Abstract] Investment securities Business combination consideration transferred common stock awards converted. Business Combination Consideration Transferred Common Stock Awards Converted Common stock awards converted Operating Lease Liability Statement Of Financial Position Extensible List Operating Lease, Liability, Statement of Financial Position [Extensible Enumeration] 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 Investment in mutual funds Percentage Of Investment In Mutual Fund The investment of pension plan assets in a mutual fund investment category as a percentage of total investment in mutual funds. Fair Value By Balance Sheet Grouping [Table] Fair Value, by Balance Sheet Grouping [Table] Less: dividends received SEC Schedule, 12-04, Cash Dividends Paid to Registrant, Consolidated Subsidiaries Pension Plans, Postretirement and Other Employee Benefits [Line Items] Pension Plans Postretirement And Other Employee Benefits [Line Items] Pension plans, postretirement and other employee benefits. Consumer Real Estate [Member] Consumer Real Estate [Member] Consumer real estate. Equity Securities [Member] Defined Benefit Plan, Equity Securities [Member] Servicing Asset at Amortized Cost Servicing Asset at Amortized Cost [Table Text Block] Deferred Tax Liabilities, Gross, Total Gross deferred tax liabilities Deferred Tax Liabilities, Gross Realized/Unrealized Gains (Losses) Defined Benefit Plan, Plan Assets Level 3 Reconciliation, Period Increase (Decrease), Total Defined Benefit Plan, Plan Assets Level 3 Reconciliation, Period Increase (Decrease) 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. Increase (decrease) in taxes: Increase Decrease In Taxes [Abstract] Increase decrease in taxes. 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] Stock Issued During Period, Value, Conversion of Units Common stock awards converted 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. Revenue from contracts with customers Revenue from Contract with Customer [Policy Text Block] Number of state and local jurisdictions where company files income tax returns Number Of State And Local Jurisdictions Where Company Files Income Tax Returns Number of state and local jurisdictions where company files income tax returns. Amortization of Intangible Assets, Total Amortization of core deposit and other intangible assets Amortization of Intangible Assets Merchant discount fee income Merchant Discount Fee Income Merchant discount fee income. Shares under equity incentive compensation plan for future grant Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Available for Grant Fixed Rate Term Loans 2.50% Due 2022 [Member] Fixed Rate Term Loans Of Two Point Five Zero Senior Notes Due Two Thousand Twenty Two [Member] Fixed rate term loans of two point five zero senior notes due two thousand twenty two. Right-of-use assets and other leasing transactions Deferred Tax Liabilities, Leasing Arrangements SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate, Loan Type SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate, Loan Type [Domain] 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 FHA gauranteed purchase amount of deliquent loan SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate, Principal Amount of Delinquent Loans Common stock, $.50 par, 250,000,000 shares authorized, 179,436,779 shares issued at December 31, 2023 and December 31, 2022 Common Stock, Value, Issued, Ending Balance Common Stock, Value, Issued, Beginning Balance Common Stock, Value, Issued, Total Common Stock, Value, Issued Post collateral requirements relating to positions Derivative Liability, Fair Value of Collateral Investment Ratings of All Privately Issued Mortgage-Backed Securities and Other Debt Securities Ratings Of Investment Securities Table [Text Block] Ratings of investment securities. 2027 Sales-Type and Direct Financing Leases, Payment to be Received, Year Four Repayments of Long-term Debt, Total Payments on long-term borrowings Repayments of Long-Term Debt Balance at beginning of period Balance at end of period Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield Interest Expense, Time Deposits, Total Time deposits Interest Expense, Time Deposits Federal Funds Purchased and Securities Sold under Agreements to Repurchase, Total Short-term borrowings Federal Funds Purchased and Repurchase Agreements Federal Funds Purchased and Securities Sold under Agreements to Repurchase Total debt securities Gross unrealized losses Investment In Debt Securities Gross Unrealized Losses Investment in debt securities gross unrealized losses. Net change in accrued interest receivable, payable Net Change In Accrued Interest Receivable Payable Net change in accrued interest receivable, payable. International Activities International Activities Disclosure [Text Block] International activities. Other credit-related commitments Other Credit Related Commitments Other credit-related commitments. Purchased Impaired Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Carrying Amount, Net Leveraged: Leveraged Leases, Net Investment in Leveraged Leases Disclosure, Investment in Leveraged Leases, Net [Abstract] 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 [Member] Commercial Bank [Member] Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Cash and Equivalents Cash and due from banks Current Fiscal Year End Date Current Fiscal Year End Date Interest Rate Reduction [Member] Contractual Interest Rate Reduction [Member] Auditor Name Auditor Name Business Acquisition, Equity Interest Issued or Issuable, Number of Shares Common shares issued, Shares Type of Borrower [Axis] Other Revenue from Operations [Member] Other Revenue from Operations. Common stock issuable, [12,217] shares at December 31, 2023; 14,031 shares at December 31, 2022 Common Stock Issuable The obligation to issue shares of company common stock in connection with deferred compensation plans. Business Combination, Consideration Transferred Total consideration Total deferred Provision for deferred income taxes Deferred Income Tax Expense (Benefit) Sensitivity Analysis of Fair Value of Interests Continued to be Held by Transferor, Servicing Assets or Liabilities, Impact of Adverse Change in Assumption [Line Items] Sensitivity Analysis of Fair Value of Interests Continued to be Held by Transferor, Servicing Assets or Liabilities, Impact of Adverse Change in Assumption [Line Items] Income tax credits Income tax expense (benefit) Income taxes Income taxes Income Tax Expense (Benefit) Lines of Credit Under Formal Agreements Schedule of Line of Credit Facilities [Table Text Block] Outside data processing and software Information Technology and Data Processing Plan participants’ contributions Defined Benefit Plan, Benefit Obligation, Contributions by Plan Participant Expense Expense [Abstract] Expense. BBB [Member] B B B Credit Rating [Member] B B B credit rating. Bayview Lending Group and Bayview Financial [Member] Bayview Lending Group And Bayview Financial [Member] Bayview Lending Group and Bayview Financial. Goodwill And Other Intangible Assets [Table] Goodwill And Other Intangible Assets [Table] Goodwill And Other Intangible Assets [Table] Long-term rate of return on plan assets Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Expected Long-Term Rate of Return on Plan Assets 2027 Long-Term Debt, Maturity, Year Four Decreases as a result of tax positions taken in prior years Decreases in unrecognized tax benefits as a result of settlements with taxing authorities Decreases as a result of tax positions taken in prior years Unrecognized Tax Benefits, Decrease Resulting from Prior Period Tax Positions Schedule Of Credit Derivatives [Table] Schedule of Credit Derivatives [Table] Interest and Fee Income, Loans and Leases, Total Loans and leases, including fees Interest and Fee Income, Loans and Leases Cash, Ending Balance Cash, Beginning Balance Cash in subsidiary bank Cash Concentration risk percentage Concentration Risk, Percentage Stock-based compensation expense Share-Based Payment Arrangement, Expense Trust Income [Member] Fiduciary and Trust [Member] Loan Restructuring Modification Loan Restructuring Modification [Domain] Disaggregation Of Revenue [Table] Disaggregation of Revenue [Table] Peoples United Financial Inc 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 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. Finite-Lived Intangible Assets, Net, Ending Balance Finite-Lived Intangible Assets, Net, Beginning Balance Net Carrying Amount Core deposit and other intangible assets Finite-Lived Intangible Assets, Net Other Real Estate Partnerships [Member] Defined Benefit Plan, Real Estate [Member] 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] Assets taken in foreclosure of defaulted loans Financing Receivable, Real Estate Acquired Through Foreclosure [Policy Text Block] Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Net of Forfeitures, Total Stock Options Outstanding, Granted Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Net of Forfeitures Debt Securities, Held-to-Maturity, Fair Value, Maturity, Allocated and Single Maturity Date, after Year One Through Five Due after one year through five years Other comprehensive income (loss), net of tax and reclassification adjustments: Other Comprehensive Income (Loss), Net of Tax [Abstract] Aggregate Intrinsic Value, Outstanding, Ending balance Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Intrinsic Value Total securities with disclosed rating, Estimated Fair Value Securities With Disclosed Rating Estimated Fair Value Fair value of investment securities excluding equities and U.S. government or government agency issued or guaranteed securities. Deferred tax assets losses on cash flow hedges. Deferred Tax Assets Losses on Cash Flow Hedges Losses on cash flow hedges Earnings per common share Earnings Per Share, Policy [Policy Text Block] Debt Securities, Held-to-Maturity, Amortized Cost, after Allowance for Credit Loss, Maturity, Allocated and Single Maturity Date, after Year One through Five Due after one year through five years Treasury stock Treasury Stock Policy [Text Block] Treasury stock. Hedging Relationship Hedging Relationship [Domain] Mortgage Banking Revenues [Member] Mortgage Banking [Member] Parent Company [Member] M&T (Consolidated) [Member] Parent Company [Member] MTLA [Member] MTLA [Member] MTLA. Notional Amount of Interest Rate Swap Agreements Outstanding Maturity Schedule of Notional Amounts of Outstanding Derivative Positions [Table Text Block] Amortization of prior service credit, tax Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), Reclassification Adjustment from AOCI, Tax Repayments of Short-Term Debt, Total Repayments of Short-Term Debt Repayment of short-term borrowings assumed in acquisition Repayment of short-term borrowings assumed in acquisition Cumulative Amount of Fair Value Hedging Adjustment Increasing (Decreasing) the Carrying Amount [Member] Measurement Basis [Axis] Financing Receivable, Allowance for Credit Losses [Line Items] Financing Receivable Allowance For Credit Losses [Line Items] Financing Receivable, Allowance for Credit Loss [Line Items] Equity in undistributed income of subsidiaries Equity In Undistributed Income Of Subsidiaries [Abstract] Equity in undistributed income of subsidiaries. Investment in financing leases Direct Financing Lease, Net Investment in Lease, before Allowance for Credit Loss Common stock, price per share Sale of Stock, Price Per Share 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. Other Diversified Mutual Fund [Member] Other Diversified Mutual Fund [Member] Other diversified mutual fund. Property, Plant and Equipment [Abstract] Property, Plant and Equipment [Abstract] Commercial Loans and Leases [Member] Commercial Loans And Leases [Member] Commercial loans and leases. Long-term Debt, Type Long-Term Debt, Type [Domain] Entity Voluntary Filers Entity Voluntary Filers Cash flows from investing activities Net Cash Provided by (Used in) Investing Activities, Continuing Operations [Abstract] Debt securities held to maturity: Debt Securities, Held-to-Maturity, Amortized Cost, after Allowance for Credit Loss, Maturity [Abstract] Amortized Cost without Allowance Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance Capital Leases [Member] Assets Held under Capital Leases [Member] Derivative Instruments And Hedging Activities Disclosures [Table] Derivative Instruments and Hedging Activities Disclosures [Table] Merger-related expenses Noncash Merger Related Costs 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&T Bank Corporation [Member] M And T [Member] M&T. Commercial Real Estate Loans [Member] Real Estate Loan [Member] Intersegment Activity Eliminated in Consolidated Totals [Member] Intersegment Eliminations [Member] Shareholders' equity Equity [Text Block] Gross unrealized losses for held to maturity Debt Securities, Held-to-Maturity, Accumulated Unrecognized Loss Interest paid during the period Interest Paid, Excluding Capitalized Interest, Operating Activities Total capital to RWA, Well capitalized Banking Regulation, Total Risk-Based Capital Ratio, Well Capitalized, Minimum Losses on loans and other assets Deferred Tax Assets Losses On Loans And Other Assets Amount of deferred tax asset attributable to taxable temporary differences from losses on loans and other assets. Variable Rate Term Loans Due 2021 [Member] Variable Rate Term Loans Due Two Thousand Twenty One [Member] Variable rate term loans due two thousand twenty one. Combination of Modification Types [Member] Combination of modification types. Series E Fixed-To-Floating Rate Non-Cumulative Perpetual Preferred Stock [Member] Series E Fixed To Floating Rate Non Cumulative Perpetual Preferred Stock [Member] Series E fixed to floating rate non cumulative perpetual preferred stock. Guaranteed amount included in the estimated residual value of leased assets associated with financing leases Capital Leases Net Investment In Financing Leases Guaranteed Residual Values Of Leased Property The amount of residual value associated with financing leases that are guaranteed by the lessees or others. Readily marketable securities Gross unrealized gains Readily Marketable Securities At Fair Value Gross Unrealized Gains Readily marketable securities at fair value gross unrealized gains. 2027 Finite-Lived Intangible Asset, Expected Amortization, Year Four 2024 Estimated amortization expense in 2022 Finite-Lived Intangible Asset, Expected Amortization, Year One Condensed Financial Information Disclosure [Abstract] Current [Member] Financial Asset, Not Past Due [Member] Retirement Plan Type Retirement Plan Type [Domain] Additional Paid in Capital, Ending Balance Additional Paid in Capital, Beginning Balance 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] Plan participants’ contributions Defined Benefit Plan, Plan Assets, Contributions by Plan Participant 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] Summary of Lease Costs for Operating Leases, Cash Paid Toward Lease Liabilities, and Weighted-Average Remaining Term and Discount Rates of Operating Leases Lease, Cost [Table Text Block] Interest cost Interest cost on benefit obligation Defined Benefit Plan, Interest Cost Fixed and variable rate four point five five percentage due two thousand twenty eight. Fixed and Variable Rate Four Point Five Five Percentage Due Two Thousand Twenty Eight [Member] 4.55% fixed/variable due 2028 [Member] Entity Entity [Domain] Term Loans 2019 [Member] Long Term Debt Two Thousand Nineteen [Member] Long term debt two thousand nineteen. Other Postretirement Benefits [Member] Other Postretirement Benefits Plan [Member] Borrowing facilities available with FHLB's amount 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. Amortization of unrealized holding losses on held-to-maturity securities, tax Other Comprehensive Income Unrealized Holding Gain Loss On Held To Maturity Securities Arising During Period Tax Amount of tax expense (benefit) of reclassification adjustment from accumulated other comprehensive income of unrealized holding gain or loss on held to maturity securities arising during period. 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 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 Summary of Minimum Lease Payments Under Noncancelable Operating Leases Lessee, Operating Lease, Liability, to be Paid, Maturity [Table Text Block] Financing Receivable, Allowance for Credit Loss, Writeoff, Total Charge-offs Financing Receivable, Allowance for Credit Loss, Writeoff Loss Contingencies [Table] Loss Contingencies [Table] Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), before Tax Net prior service cost Net accrued asset (liability) recognized in the Consolidated Balance Sheet Pension And Other Postretirement Defined Benefit Plans Assets Liabilities Net Pension and other postretirement defined benefit plans assets liabilities net. Weighted-average interest rate Loans and leases average rate Debt, Weighted Average Interest Rate Investment, Name Investment, Name [Domain] Debt Maturity, Start Year Debt Instrument, Maturity Date Range, Start Accounting Policies [Abstract] Segments Segments [Domain] 2028 Finite-Lived Intangible Asset, Expected Amortization, Year Five 2028 Lessee, Operating Lease, Liability, to be Paid, Rolling Year Five Amortization of actuarial gains (losses), before tax Amortization of actuarial (loss) gain 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] Owned Assets [Member] Owned Assets [Member] Owned assets. Share Based Compensation Arrangement By Share Based Payment Award [Line Items] Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items] Interest Income [Member] Interest Income [Member] Credit card interchange fee income Credit Card Interchange Fee Income Credit card interchange fee income. 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. Business Acquisition, Pro Forma Information [Table Text Block] Summary of Acquisition, Pro Forma Information Impact on fair value of 20% adverse change Sensitivity Analysis of Fair Value, Transferor's Interests in Transferred Financial Assets, Impact of 20 Percent Adverse Change in Discount Rate Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net Net assets acquired Variable interest rate of Senior Notes /Junior Subordinated Debentures Debt Instrument, Interest Rate, Effective Percentage Capitalized servicing rights Assets or Liabilities that Relate to Transferor's Continuing Involvement in Securitized or Asset-Backed Financing Assets, Policy [Policy Text Block] Reduction of estimated fair value losses on hedging instruments Reduction In Estimated Fair Value Losses On Hedging Instruments Reduction in estimated fair value losses on hedging instruments. Tier 1 capital to RWA, Minimum Ratio Banking Regulation, Tier 1 Risk-Based Capital Ratio, Actual Revolving Loans [Member] Revolving Credit Facility [Member] Federal Home Loan Bank, Advances, Maturities Summary, Fixed Rate, Total Fixed rates advances from FHLB Federal Home Loan Bank, Advances, Maturities Summary, Fixed Rate Foreign Currency and Other Option and Futures Contracts [Member] Foreign Currency And Other Option And Futures Contracts [Member] Foreign currency and other option and futures contracts. Gains (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. 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Interest income Interest and Dividend Income, Operating [Abstract] Medicare Part D reimbursement Defined Benefit Plan, Benefit Obligation, Prescription Drug Subsidy Receipt FHLB Advances [Member] FHLBs Facility [Member] Federal Home Loan Bank Advances [Member] Derivative Asset, Fair Value, Gross Asset, Total Asset Derivatives, Fair Value Derivative Asset, Subject to Master Netting Arrangement, before Offset Delinquent period of loans resulting in accrued interest being charged against income Delinquent Period Of Loans Resulting In Accrued Interest Being Charged Against Income Period of time that delinquent loan principal or interest will result in previously accrued interest being charged against income. 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] COVID-19 [Member] Unusual Risk or Uncertainty, Nature [Axis] Cash paid toward lease liabilities Operating Lease, Payments 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] Increment in amortization period. 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Bayview Lending Group [Member] Bayview Lending Group [Member] Bayview Lending Group. 2024 Derivative Notional Amount To Expire In Next Twelve Months The notional amount of interest rate swap agreements entered into for risk management purposes that mature in next twelve months after the balance sheet date. Domestic Equity Securities [Member] Defined Benefit Plan, Equity Securities, US [Member] Cash Flow Hedges and Other [Member] Cash Flow Hedges And Other [Member] Cash flow hedges and other. 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] Number of reportable segments Number of Reportable Segments Direct Financing Lease, Lease Receivable Lease payments receivable 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 Commitments to sell real estate loans Commitments To Sell Real Estate Loans Net Commitments to sell real estate loans net. 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 Due from consolidated bank subsidiaries Due From Subsidiaries [Abstract] Due from subsidiaries. Pension Benefits [Member] Pension Plan [Member] Maturity of Long-term Borrowings Schedule of Maturities of Long-Term Debt [Table Text Block] Domestic Mutual Fund Debt Securities [Member] Domestic Mutual Fund Debt Securities [Member] Domestic mutual fund debt securities. Combination of Concession Types [Member] Combination Of Concession Types [Member] Combination of concession types. Total other income Noninterest Income Net deferred tax asset Deferred Tax Assets, Net Schedule Of Borrowings [Table] Schedule Of Borrowings [Table] Schedule of borrowings. Supplemental Pension Plan [Member] Supplemental Pension Plan [Member] Supplemental pension plan. Percentage of common stock in total plan assets Defined Benefit Plan, Plan Assets, Actual Allocation, Percentage Capitalized servicing assets Transfers and Servicing of Financial Assets [Text Block] 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 Mortgage-backed securities Debt Securities, Available-for-Sale, Maturity, without Single Maturity Date, Amortized Cost Fixed Rate Term Loans Of Two Point Zero Five Senior Notes Due Two Thousand Twenty Fixed Rate Term Loans Of Two Point Zero Five Senior Notes Due Two Thousand Twenty [Member] Fixed rate term loans of two point zero five senior notes due two thousand twenty. 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 Payments for Repurchase of Common Stock Collateral Held Collateral Held [Domain] Discounted Cash Flows [Member] Discounted Cash Flows [Member] Discounted cash flows. Finite-Lived Intangible Assets, Major Class Name Finite-Lived Intangible Assets, Major Class Name [Domain] 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 Cash Flow Hedges and Other [Member] Accumulated Cash Flow Hedges And Other [Member] Accumulated cash flow hedges and other. Credit Derivatives [Line Items] Credit Derivatives [Line Items] Stock Options Outstanding, Exercised Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercises in Period Consolidation Consolidation, Policy [Policy Text Block] Business combination recognized identifiable assets acquired and liabilities assumed borrowings. Business combination recognized identifiable assets acquired and liabilities assumed borrowings Borrowings 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 Entities [Table] Senior Notes Issued in July 2018 [Member] Senior Notes Issued July Two Thousand And Eighteen [Member] Senior notes issued July two thousand and eighteen. Funds available for payment of dividends to M&T from banking subsidiaries Funds Available For Payment Of Dividends To Parent Company From Banking Subsidiaries Amount of dividends available for payment to parent company after computation of banking subsidiaries earnings for the current year and preceding two years. Other Debt Securities [Member] Other Debt Obligations [Member] Stock Issued During Period, Value, Acquisitions Common stock issued 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 Stock options exercisable period, maximum Share Based Compensation Arrangement By Share Based Payment Award Award Expiration Period Share Based Compensation Arrangement By Share Based Payment Award Award Expiration Period Entity Interactive Data Current Entity Interactive Data Current Subordinated Debt, Ending Balance Subordinated Debt, Beginning Balance Subordinated Debt, Total Subordinated notes Subordinated Debt Acquisition of bank and bank holding company, Common stock issued Stock Issued Preferred stock dividend rate 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. Net unrecognized tax benefits that, if recognized, would impact the effective income tax rate Unrecognized Tax Benefits that Would Impact Effective Tax Rate 2026 Finite-Lived Intangible Asset, Expected Amortization, Year Three Sensitivity Analysis Of Fair Value Of Interests Continued To Be Held By Transferor Servicing Assets Or Liabilities [Table] Schedule of Sensitivity Analysis of Fair Value, Transferor's Interests in Transferred Financial Assets [Table] Credit Facility Credit Facility [Domain] Obligations of States and Political Subdivisions [Member] US States and Political Subdivisions Debt Securities [Member] Other noninterest expense Non Interest Expense Excluding Amortization And Depreciation Non interest expense excluding amortization and depreciation. Text Block [Abstract] Equity [Abstract] Less: imputed interest Less: imputed interest Lessee, Operating Lease, Liability, Undiscounted Excess Amount 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. Restricted Stock Outstanding, Granted Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period Entity Well-known Seasoned Issuer Entity Well-known Seasoned Issuer Business Acquisition, Pro Forma Net Income (Loss) Net income Pass [Member] Pass [Member] Revision of Prior Period Revision of Prior Period [Axis] Non PCD acquired loans. Non P C D Acquired Loans Member Non PCD Acquired Loans [Member] Non-PCD Southern Financial Capital Trust III - due 2033 [Member] Southern Financial Capital Trust Three Variable Rate Due Two Zero Three Three [Member] Southern Financial Capital Trust III - due 2033. Interest Paid, Including Capitalized Interest, Operating and Investing Activities, Total Interest paid during the year Interest Paid, Including Capitalized Interest, Operating and Investing Activities Total debt securities Estimated fair value Investment In Debt Securities Estimated Fair Value Investment in debt securities estimated fair value. Consumer [Member] Consumer Portfolio Segment [Member] Mortgage-backed securities Debt Securities, Held-to-Maturity, Maturity, without Single Maturity Date, Fair Value Weighted-Average Exercise Price, Exercised Share-Based Compensation Arrangements by Share-Based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price Entity Incorporation, State or Country Code Entity Incorporation, State or Country Code Consolidated Statement of Cash Flows Cash and Cash Equivalents, Policy [Policy Text Block] 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 Assumed Weighted-Average Rates Used to Determine Benefit Obligations Assumed Weighted Average Rates Used To Determine Benefit Obligations Table [Text Block] Assumed weighted-average rates used to determine benefit obligations. Purchase credit-deteriorated. Purchase Credit-Deteriorated Derivatives, Fair Value [Line Items] Derivatives, Fair Value [Line Items] Equity Components Equity Components [Axis] Date of change in the dividend rate Preferred Stock Dividend Rate Modifications Date Of Change The date at which the preferred stock dividend rate or the frequency of dividend payments, or both, will change. Fair Values of Company's Pension Plan Assets by Asset Category Defined Benefit Plan Fair Value Of Plan Assets Disclosure Table [Text Block] Defined benefit plan fair value of plan assets disclosure. Cumulative effect of change in accounting principle ?equity securities Cumulative Effect On Retained Earnings Before Tax Cumulative effect on retained earnings before tax. Investments, Debt and Equity Securities [Abstract] All Other [Member] Other Segments [Member] Defined Benefit Plan, Plan Assets, Amount, Total Defined benefit plan fair value of plan assets Fair value of plan assets at beginning of year Fair value of plan assets at end of year Defined Benefit Plan, Plan Assets, Amount LIBOR [Member] LIBOR [Member] LIBOR. Pension plans and other postretirement benefits Retirement Benefits [Text Block] BB [Member] Bb [Member] BB. Commercial Loans [Member] Commercial Loans [Member] Commercial loans. Payments to Acquire Businesses, Gross Cash Less: Preferred stock dividends Preferred Stock Dividends, Income Statement Impact Amount of initial margin posted Collateral Already Posted, Aggregate Fair Value Sales and securitizations of financial assets Transfers and Servicing of Financial Assets, Policy [Policy Text Block] Other securities, Gross unrealized losses Other Securities Gross Unrealized Losses Other securities gross unrealized losses. Income 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 investment securities Equity Securities, FV-NI, Cost Significant Accounting Policies [Line Items] Significant Accounting Policies [Line Items] Significant accounting policies. Series G Fixed-Rate Reset Non-Cumulative Perpetual Preferred Stock [Member] Series G Fixed Rate Reset Non Cumulative Perpetual Preferred Stock [Member] Series G fixed rate reset non-cumulative perpetual preferred stock. 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Federal Current Federal Tax Expense (Benefit) Schedule of Equity Method Investments [Line Items] Schedule of Equity Method Investments [Line Items] Goodwill, Ending Balance Goodwill, Beginning Balance Goodwill, Total Goodwill Goodwill Proceeds from issuance of Series I and G preferred stock Proceeds from Issuance of Preferred Stock and Preference Stock Proceeds from issuance of Series I preferred stock Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Table] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table] Money-Market Investments [Member] Money Market Investments [Member] Money market investment. Schedule Of Financing Receivable Allowance For Credit Losses [Table] Financing Receivable, Allowance for Credit Loss [Table] Statement of Cash Flows [Abstract] Unrealized gain 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) Directors’ Stock Compensation Programs [Member] Director [Member] Asset-backed notes weighed average estimated life Asset Backed Notes Weighred Average Estimated Life Asset backed notes weighred average estimated life Variable interest entities and asset securitizations Variable Interest Entities And Asset Securitizations [Text Block] Variable interest entities and asset securitizations. Capitalized servicing rights Amortized value, Beginning balance Amortized value, ending balance 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] Sales-Type and Direct Financing Leases, Payment to be Received, Maturity [Table Text Block] Minimum Future Lease Payments to be Received from Lease Financings Business combination recognized identifiable assets acquired and liabilities assumed loans and leases net. Business Combination Recognized Identifiable Assets Acquired and Liabilities Assumed Loans and Leases Net Loans and leases Trust preferred capital securities Trust Preferred Securities Included In Tier One Capital Percent Trust preferred securities included in tier one capital percent. Income Tax Authority Income Tax Authority [Domain] Preferred stock, dividend declared per share 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 Premises and equipment Property, Plant and Equipment, Policy [Policy Text Block] Segment Reporting Information [Line Items] Segment Reporting Information [Line Items] Concentration Risk Benchmark Concentration Risk Benchmark [Axis] Document Annual Report Document Annual Report Unrealized losses on cash flow hedges Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification and Tax Other income Other Income Regulatory Assets [Abstract] Regulatory assets. Debt Security Category Debt Security Category [Axis] Common stock, par value Common Stock, Par or Stated Value Per Share Discount rate Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate Income available to common shareholders: Net income available to common shareholders Net Income (Loss) Available to Common Stockholders, Basic [Abstract] Impact on fair value of 20% adverse change Sensitivity Analysis of Fair Value, Transferor's Interests in Transferred Financial Assets, Impact of 20 Percent Adverse Change in Other Assumption Interest rate of debt instrument Debt Instrument, Interest Rate, Stated Percentage Unrecognized compensation cost expected to be recognized over a weighted-average period (in years) Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition Long-Lived Tangible Asset Long-Lived Tangible Asset [Axis] Other Short-Term Borrowings Commercial Real Estate [Member] Commercial Real Estate Segment [Member] Commercial real estate segment. FHA Guaranteed Mortgage Loans [Member] Federal Housing Administration Loan [Member] Reconciliation Of Unrecognized Tax Benefits [Table] Reconciliation Of Unrecognized Tax Benefits [Table] Reconciliation Of Unrecognized Tax Benefits [Table] Salaries and employee benefits. Salaries and employee benefits Schedule Of Share Based Compensation Arrangements By Share Based Payment Award [Table] Schedule of Share-Based Compensation Arrangements by Share-Based Payment Award [Table] Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets [Abstract] Identifiable assets Maximum [Member] Maximum [Member] Cumulative effect of change in accounting principle — credit losses New Accounting Pronouncement Or Change In Accounting Principle Effect Of Adoption Quantification1 New accounting pronouncement or change in accounting principle effect of adoption quantification. Due after ten years Debt Securities, Available-for-Sale, Amortized Cost, Maturity, Allocated and Single Maturity Date, after Year 10 Daily-average amount outstanding Short-Term Debt, Average Outstanding Amount Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities [Abstract] Liabilities and preferred stock: 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] Other Income And Expenses [Table] Other income and expenses. Qualified affordable housing project tax benefits, net Effective Income Tax Rate Reconciliation, Tax Credit, Amount, Total Effective Income Tax Rate Reconciliation, Tax Credit, Amount Series H Preferred Stock [Member] Series H Preferred Stock [Member] Guaranteed amount included in the estimated residual value of leased assets associated with direct financing leases Capital Leases Net Investment In Direct Financing Leases Guaranteed Residual Values Of Leased Property The amount of residual value associated with direct financing leases that are guaranteed by the lessees or others. Reconciliation of Beginning and Ending Amount of Unrecognized Tax Benefits Schedule of Unrecognized Tax Benefits Roll Forward [Table Text Block] Federal, State and Local Tax [Member] Federal State And Local Tax [Member] Federal state and local tax. Secured overnight financing rate plus basis points. Secured overnight financing rate plus basis points 2033 Derivative notional amount to expire in year ten Derivative notional amount to expire in year ten. 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] Short-term Debt, Type Short-Term Debt, Type [Domain] Noninterest-bearing Deposit Liabilities, Domestic, Total Noninterest-bearing deposits Noninterest-bearing deposits Noninterest-Bearing Deposit Liabilities, Domestic FHA gauranteed mortgage loan 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 Debt and Equity Securities, Gain (Loss), Total Gain (loss) on bank investment 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 Repayments and other reductions of borrowings by directors, certain officers and their associates Loans and Leases Receivable, Related Parties, Proceeds 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. Purchase price of servicing rights Payments to Acquire Mortgage Servicing Rights (MSR) Internal Credit Assessment Internal Credit Assessment [Domain] 2027 Defined Benefit Plan, Expected Future Benefit Payment, Year Four Incremental Common Shares Attributable to Share-based Payment Arrangements, Total Plus: Incremental shares from assumed conversion of stock-based compensation awards and warrants to purchase common stock Incremental Common Shares Attributable to Dilutive Effect of Share-Based Payment Arrangements International Activities [Table] International Activities [Table] International Activities [Table] Investment Securities in Continuous Unrealized Loss Position Investment Securities In Continuous Unrealized Loss Position Table [Text Block] Investment securities in continuous unrealized loss position. Document Financial Statement Error Correction [Flag] 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 2026 Derivative notional amount to expire in year three. Derivative Notional Amount To Expire In Year Three Other expense Noninterest Expense [Abstract] Preferred equity. Preferred Equity Preferred stock Collateralized mortgage obligations, Estimated fair value Collateralized Mortgage Obligations Estimated Fair Value Fair value of collateralized mortgage obligations included in mortgage-backed securities. Segment information Segment Reporting Disclosure [Text Block] Cash flows from financing activities Net Cash Provided by (Used in) Financing Activities, Continuing Operations [Abstract] Carrying Amounts and Estimated Fair Value for Financial Instrument Assets (Liabilities) Fair Value, by Balance Sheet Grouping [Table Text Block] City Area Code City Area Code State and local Deferred State and Local Income Tax Expense (Benefit) 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 purchased credit deteriorated loans. Allowance On Acquired Purchased Credit Deteriorated Loans Allowance on acquired PCD loans Investment securities Investments in Debt and Marketable Equity Securities (and Certain Trading Assets) Disclosure [Text Block] Consolidation Items Consolidation Items [Axis] Asset-backed notes Asset-Backed Securities, at Carrying Value Document Information [Line Items] Intersegment Activity Eliminated in Arriving at Consolidated Totals was Included in "All Other" Category Segment, Reconciliation of Other Items from Segments to Consolidated [Table Text Block] 7.41% fixed/variable due 2029 [Member] Fixed and Variable Rate Seven Point Four One Percentage Due Two Thousand Twenty Nine [Member] Fixed and variable rate seven point four one percentage due two thousand twenty nine. Later years Lessee, Operating Lease, Liability, to be Paid, after Rolling Year Five Proceeds from Issuance of Long-term Debt, Total Proceeds from long-term borrowings Proceeds from Issuance of Long-Term Debt Retirement benefits Deferred Tax Liabilities Retirement Benefits Deferred tax liabilities retirement benefits. 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] Wilmington Trust, N.A. [Member] Wilmington Trust Na [Member] Wilmington Trust N.A. Defined Benefit Plan, Plan Assets, Business Combination Business combinations Weighted-average shares outstanding: Weighted Average Number of Shares Outstanding, Basic [Abstract] Rate of increase in future compensation levels Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Rate of Compensation Increase Change in benefit obligation: Defined Benefit Plan, Change in Benefit Obligation [Roll Forward] Commercial Loans and Commercial Real Estate [Member] Commercial Loans And Commercial Real Estate [Member] Commercial loans and commercial real estate. Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment, Ending Balance Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment, Beginning Balance Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment, Total Less: accumulated depreciation and amortization Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment 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. Gains (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. Benefits paid Defined Benefit Plan, Plan Assets, Benefits Paid Loans and leases Loans and leases, net Loans and Leases Receivable, Net Amount Weighted Average Number of Shares Outstanding, Basic, Total Weighted-average shares outstanding Weighted Average Number of Shares Outstanding, Basic Effective Income Tax Rate Reconciliation, Other Reconciling Items, Amount, Total Other Effective Income Tax Rate Reconciliation, Other Reconciling Items, Amount Depreciation and amortization Deferred Tax Liability Depreciation And Amortization Deferred tax liability depreciation and amortization Salaries and employee benefits Labor and Related Expense Income taxes attributable to gains or losses on bank investment securities Income Taxes Attributable To Gains Or Losses On Bank Investment Securities Income taxes attributable to gains or losses on bank investment securities. Cumulative effect of change in accounting principle ?equity securities Cumulative Effect On Retained Earnings Tax Cumulative effect on retained earnings tax. 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. Fixed Rate Term Loans 2.90% Due 2025 [Member] Fixed Rate Term Loans Of Senior Notes Due Two Thousand Twenty Five [Member] Fixed rate term loans of senior notes due two thousand twenty five. Class of Financing Receivable, Type of Borrower [Domain] Investment in partnership carrying amount Investments In Variable Interest Entity Carrying Amount The carrying amount of investments in variable interest entity. Amortization of actuarial gains (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. Investments in trust preferred entities (note 20) Investments In Trust Preferred Entities Investments in trust preferred entities. International Mutual Fund Equity Securities [Member] International Mutual Fund Equity Securities [Member] International mutual fund equity securities. Other Hedge Funds [Member] Hedge Funds [Member] Statement [Table] Statement [Table] Derivatives not designated as hedging instruments, Derivatives Gain (Loss) on Derivative Instruments Held for Trading Purposes, Net Purchased Impaired [Member] Purchased Impaired [Member] Purchased impaired. Two Independent Pricing Quotes [Member] Two Independent Pricing Quotes [Member] Two independent pricing quotes. Business Combination, Recognized Identifiable Asset Acquired and Liability Assumed, Lease Obligation Assumed in business combination Ending balance, net Servicing Asset at Amortized Cost, Fair Value Document Fiscal Period Focus Document Fiscal Period Focus Total lease payments Lessee, Operating Lease, Liability, to be Paid Effect of 25 basis point decrease in rate of return on pension expense Defined Benefit Plan Effect Of Twenty Five Basis Point Decrease In Rate Of Return On Pension Expense Defined benefit plan effect of twenty five basis point decrease in rate of return on pension expense. Income (Loss) from Equity Method Investments, Total Income (loss) from equity method investments Income (Loss) from Equity Method Investments Investment Securities [Member] Securities Investment [Member] Commercial Mortgage Sub Servicing Loan [Member] Sub Servicing Loan One [Member] Sub servicing loan one. Derivatives Not Designated and Qualifying as Hedging Instruments [Member] Not Designated as Hedging Instrument [Member] Rate of increase in future compensation levels Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Rate of Compensation Increase Schedule Of Sale Of Subsidiary [Abstract] Schedule of sale of subsidiary. Fixed Rate Term Loans 2.25% Due 2019 [Member] Fixed Rate Term Loans Of Senior Notes Due Two Thousand Nineteen One [Member] Fixed rate term loans of senior notes due two thousand nineteen one. 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. Collateral Held Collateral Held [Axis] Statement [Line Items] Statement [Line Items] Interest rate swap agreements used for interest rate risk management Interest Rate Swap Agreements Used For Interest Rate Risk Management Interest rate swap agreements used for interest rate risk management. Gains (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 Interest on short-term borrowings Taxable-equivalent adjustment Taxable Equivalent Adjustment Taxable equivalent adjustment. Long-term Borrowings Schedule of Long-Term Debt Instruments [Table Text Block] 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 Reclassification of income tax effects to retained earnings Reclassification of income tax effects to retained earnings Tax Cuts And Jobs Act Of2017 Reclassification From A O C I To Retained Earnings Tax cuts and jobs act of 2017 reclassification from AOCI to retained earnings. Increase (Decrease) in Deposits, Total Increase (Decrease) in Deposits Net increase (decrease) in deposits Amounts and Interest Rates of Short-term Borrowings Schedule of Short-Term Debt [Table Text Block] 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 Valuation allowance Servicing Asset at Amortized Cost, Increase (Decrease) for Valuation Allowance Adjustment Total lease cost Lease, Cost 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 Liabilities Assumed Fair value of Liabilities assumed Performance share unit dividends Dividends Performance Share Units Dividends performance share units. Defined Benefit Plan, Net Periodic Benefit Cost (Credit) Excluding Service Cost, Statement of Income or Comprehensive Income [Extensible Enumeration] 2025 Derivative Notional Amount To Expire In Year Two The notional amount of interest rate swap agreements entered into for risk management purposes that mature during the second year after the balance sheet date. Percentage of eligible employees contribution for Retirement Savings Plan Percentage Of Eligible Employees Contribution For Retirement Savings Plan Maximum percentage of qualified compensation that eligible employees may contribute to the defined contribution plan. 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Common Stock [Member] Common Stock [Member] Debt Instrument [Line Items] Debt Instrument [Line Items] Finite-Lived Intangible Assets, Net, Amortization Expense, Rolling Maturity [Abstract] Total Debt Securities [Member] Defined Benefit Plan, Debt Security [Member] Derivative Asset, Fair Value, Amount Not Offset Against Collateral, Total Aggregate fair value of derivative financial instruments in asset position Derivative Asset, Subject to Master Netting Arrangement, before Offset of Collateral 2027 Lessee, Operating Lease, Liability, to be Paid, Rolling Year Four Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), after Reclassification Adjustment, before Tax, Total Total recognized in other comprehensive income, pre-tax Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), after Reclassification Adjustment, before Tax Decreases in unrecognized tax benefits because appliable returns are no longer subject to examination Decreases in unrecognized tax benefits because appliable returns are no longer subject to examination Unrecognized Tax Benefits, Reduction Resulting from Lapse of Applicable Statute of Limitations Cash and Cash Equivalents, at Carrying Value, Total Cash and cash equivalents Cash and cash equivalents at beginning of year Cash and cash equivalents at end of year 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. 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Treasury stock - common, at cost - [13,300,298] shares at December 31, 2023; 10,165,419 shares at December 31, 2022 Treasury Stock, Value, Ending Balance Treasury Stock, Value, Beginning Balance Treasury Stock, Value, Total Treasury Stock, Value Cover [Abstract] 3.40% due 2027 [Member] Subordinated Notes Due Two Zero Two Seven [Member] Subordinated notes due two zero two seven. Amortized Cost Impaired Financing Receivable, Related Allowance Allowance for credit losses at acquisition Allowance for credit losses at acquisition Current Current Income Tax Expense (Benefit), Continuing Operations [Abstract] Document Fiscal Year Focus Document Fiscal Year Focus Unrealized gains Deferred Tax Liabilities Unrealized Gains On Investment Securities Amount of deferred tax liability attributable to taxable temporary differences from unrealized gains on investment securities. 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Restricted Stock Awards [Member] Restricted Stock Awards [Member] Restricted Stock Awards [Member] Financial guarantees and indemnification contracts Commitments Regarding Financial Guarantees And Indemnification Contracts Commitments regarding financial guarantees and indemnification contracts. Capital conservation buffer Capital Conservation Buffer Ratio Capital conservation buffer ratio. State and local Current State and Local Tax Expense (Benefit) Goodwill And Other Intangible Assets [Line Items] Goodwill And Other Intangible Assets [Line Items] Goodwill and other intangible assets. Right-of-use assets obtained in exchange for new operating lease liabilities 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] 3.55% Fixed Rate Due 2023 [Member] Fixed Rate Three Point Five Five Percentage Due Two Thousand Twenty Three [Member] Fixed rate three point five five percentage due two thousand twenty three. Total Debt Securities [Member] Debt Security [Member] Debt security. M&T Insurance Agency, Inc. M&T Insurance Agency, Inc [Member] Marketing and Advertising Expense, Total Advertising and marketing Marketing and Advertising Expense Variable Rate Senior Notes [Member] Floating Rate Senior Notes [Member] Floating rate senior notes. Business Acquisition, Acquiree Business Acquisition, Acquiree [Domain] Total other comprehensive income (loss), tax Other Comprehensive Income (Loss), Tax M&T Bank [Member] Legal Entity [Axis] Pre-tax adjustment to accumulated other comprehensive income Defined Benefit Plan, Accumulated Other Comprehensive (Income) Loss, before Tax Financial Instrument Financial Instrument [Axis] Adjusted weighted-average 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. Summary of Restricted Stock and Restricted Stock Unit Activity Share-Based Payment Arrangement, Restricted Stock and Restricted Stock Unit, Activity [Table Text Block] Loans And Leases Receivable [Line Items] Loans And Leases Receivable [Line Items] Loans and leases receivable. 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Accounting Standards Update Accounting Standards Update [Domain] Prepaid asset recognized in the Consolidated Balance Sheet Assets for Plan Benefits, Defined Benefit Plan Minority interest in Bayview Lending Group LLC Equity Method Investment, Ownership Percentage Outstanding balance of secured debt Certain Loans Acquired in Transfer Accounted for as Debt Securities, Outstanding Balance M&T Bank [Member] M And T Bank [Member] M&T Bank. Schedule of Finite-Lived Intangible Assets, Future Amortization Expense [Table Text Block] Summary of Estimated Amortization Expense 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] Long term debt two thousand twenty two. Long Term Debt Two Thousand Twenty Two [Member] Term Loans 2022 [Member] Defined Benefit Plan, ultimate health care cost trend rate Defined Benefit Plan, Ultimate Health Care Cost Trend Rate Payments to Acquire Debt Securities, Available-for-Sale Purchases of investment securities Available for sale Bank Subsidiaries [Member] Subsidiaries [Member] Medicare Part D reimbursement Defined Benefit Plan, Plan Assets, Prescription Drug Subsidy Receipt Leases Leases [Abstract] Finite-Lived Intangible Asset, Expected Amortization, after Year Five Later years Derivative, Gain (Loss) on Derivative, Net, Total Derivatives in fair value hedging relationships, Derivatives Derivative, Gain (Loss) on Derivative, Net 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 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 Debt maturity date Debt Instrument Maturity Year Debt instrument maturity year. 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Pledged Status [Domain] Other Income and Other Expense Interest and Other Income [Table Text Block] Gross deferred tax assets Deferred Tax Assets, Gross Loans and leases Receivable [Policy Text Block] Amortization of unrealized holding losses on held-to-maturity securities Other Comprehensive Income Unrealized Holding Gain Loss On Held To Maturity Securities Arising During Period Net Of Tax Amount after tax of increase (decrease) in accumulated other comprehensive income (loss) related to the reclassification adjustment for other than temporary impairment (OTTI) related to factors other than credit loss on a previously impaired investment on held-to-maturity security. Actuarial (gain) loss Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss) Net Increase Decrease In Loan Servicing Advances The net cash outflow or inflow for the increase (decrease) of loan servicing advances. 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Unrealized holding gains (losses), net of tax OCI, Debt Securities, Available-for-Sale, Unrealized Holding Gain (Loss), before Adjustment, after Tax Amortization Servicing Asset at Amortized Cost, Amortization 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 Other Acquired [Member] Other Acquired Loans [Member] Balance of acquired loans that were not purchased impaired. Maturity Period 2024 [Member] Maturity Period One [Member] Maturity Period One [Member]. Recreational Finance [Member] Recreational Finance [Member] Recreational finance. 2025 Lessee, Operating Lease, Liability, to be Paid, Rolling Year Two Other Assets, Total Other assets Other Assets Share-Based Payment Arrangement [Abstract] Cash Flow Hedges Derivative Instruments at Fair Value, Net, Total Cash flow hedges drerivative instruments income Cash Flow Hedges Derivative Instruments at Fair Value, Net Taxes Defined Benefit Plan Accumulated Other Comprehensive Income Tax The amount of income tax related to the net gain (loss), prior service cost (credit), and transition assets (obligations), as well as minimum pension liability if still remaining, included in accumulated other comprehensive income associated with a defined benefit pension or other postretirement plan(s) because they have yet to be recognized as components of net periodic benefit cost. 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Interest Rate Contracts [Member] Interest Rate Contract [Member] 2025 Sales-Type and Direct Financing Leases, Payment to be Received, Year Two Total gains realized/unrealized: Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] Accrued Liabilities and Other Liabilities, Total Accrued expenses and other liabilities Accrued Liabilities and Other Liabilities Fixed Rate Term Loans 2.625% Due 2021 [Member] Fixed Rate Term Loans Of Senior Notes Due Two Thousand Twenty One [Member] Fixed rate term loans of senior notes due two thousand twenty one. 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 December 31, 2023 and December 31, 2022; Liquidation preference of $10,000 per share: 140,000 shares at December 31, 2023 and December 31,2022; Liquidation preference of $25 per share: 10,000,000 shares at December 31, 2023 and December 31, 2022 Preferred Stock, Value, Issued, Ending Balance Preferred Stock, Value, Issued, Beginning Balance Preferred Stock, Value, Issued, Total Carrying Value Preferred Stock, Value, Issued Entity Small Business Entity Small Business Total Impaired Financing Receivable, Unpaid Principal Balance Unpaid principal balance Entity Shell Company Entity Shell Company Sale of Stock, Number of Shares Issued in Transaction Common stock issued in transaction Investment Type Investment Type [Axis] 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 Fair value of Assets acquired (noncash) Total loans Financing Receivable, before Allowance for Credit Loss Total loans Loans Loans Receivable [Abstract] Loans receivable. 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. CET1 to RWA, Well Capitalized Common Equity Tier One Risk Based Capital To Well Capitalized To Risk Weighted Assets Common equity tier one risk based capital to well capitalized to risk weighted assets. Leverage - Tier 1 capital to average total assets, as defined Banking Regulation, Tier 1 Leverage Capital Ratio, Capital Adequacy, Minimum Southern Financial Statutory Trust I - 10.60%, due 2030 [Member] Southern Financial Statutory Trust One Fixed Rates Due Two Zero Three Zero [Member] Southern Financial Statutory Trust I - 10.60%, due 2030. Entity Address, Address Line One Entity Address, Address Line One Sales Revenue, Net [Member] Revenue Benchmark [Member] Other information Other Lease Cost Information [Abstract] Other lease cost information. Direct Financing Lease, Unguaranteed Residual Asset Estimated residual value of leased assets Effect of 25 basis point increase in discount rate on benefit obligation Defined Benefit Plan Decrease Of Twenty Five Basis Point Increase In Discount Rate On Benefit Obligation Defined benefit plan decrease of twenty five basis point increase in discount rate on benefit obligation. ACL for non-purchased credit deteriorated loan and leases. A C L for non-purchased credit deteriorated loan and leases ACL for non-PCD loan and leases Option Indexed to Issuer's Equity, Type Option Indexed to Issuer's Equity, Type [Axis] Fair Value Hedges [Member] Fair Value Hedging [Member] BSB Capital Trust I - 8.125%, due 2028 [Member] Bsb Capital Trust One Fixed Rates Due Two Zero Two Eight [Member] BSB Capital Trust I - 8.125%, due 2028. Allowance for Loan and Lease Losses Write-offs, Net, Total Net charge-offs Allowance for Loan and Lease Losses, Writeoff, Net Net fair value of derivative financial instruments in a net liability position Derivative, Net Liability Position, Aggregate Fair Value Finite-Lived Intangible Assets, Gross, Total Gross Carrying Amount Finite-Lived Intangible Assets, Gross Allfirst Asset Trust - due 2029 [Member] Allfirst Asset Trust Variable Rates Due Two Zero Two Nine [Member] Allfirst Asset Trust - due 2029. Director and Certain Officers [Member] Director And Certain Officers [Member] Director and certain officers. Other assets Other Assets, Fair Value Disclosure Preferred shares redemption date Preferred Stock, Redemption Date Commercial Banking [Member] Commercial Banking [Member] Commercial banking segment. Other revenues from operations Noninterest Income, Other Operating Income Total interest income Interest and Dividend Income, Operating Amortization of actuarial gains (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. Weighted-average interest rate Short-Term Debt, Weighted Average Interest Rate, at Point in Time Issued and Outstanding Preferred Stock Schedule of Stock by Class [Table Text Block] Discretionary Portfolio [Member] Discretionary Portfolio [Member] Discretionary portfolio segment. 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Commitments to Sell Real Estate Loans [Member] Commitments To Sell Real Estate Loans [Member] Commitments to sell real estate loans. Other Securities [Member] Other Securities [Member] Other securities. Geographic Distribution Geographic Distribution [Domain] First Maryland Capital II - due 2027 [Member] First Maryland Capital Two Variable Rates Due Two Zero Two Seven [Member] First Maryland Capital II - due 2027. Long-term Debt, Type Long-Term Debt, Type [Axis] Commercial Mortgage Loans [Member] Commercial Loan [Member] Fair Value, Measurements, Nonrecurring [Member] Fair Value, Nonrecurring [Member] Right-of-use assets acquired in business combination. Right-of-use assets acquired in business combination Right-of-use assets acquired in business combination Consumer loan delinquent period threshold for consideration for charge off Consumer Loan Delinquent Period Threshold For Consideration For Charge Off The period of delinquency threshold for consumer loans that generally results in the loan being charged off. All Other [Member] All Other [Member] Corporate, Non-Segment [Member] Significant Observable Inputs (Level 2) [Member] Fair Value, Inputs, Level 2 [Member] Class of Financing Receivable Class of Financing Receivable [Axis] M&T Equity Securities [Member] M And T Equity Securities [Member] M and T equity securities. Shares issued Share-Based Compensation Arrangement by Share-Based Payment Award, Shares Issued in Period 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. Noninterest income Noninterest Income Expense Amount of noninterest income net of other-than-temporary impairment of marketable securities. Estimated residual value of leased assets Leveraged Leases, Net Investment in Leveraged Leases Disclosure, Residual Value of Leased Assets Securities [Member] Securities. Investment in leveraged leases Leveraged Leases, Net Investment in Leveraged Leases Disclosure, Investment in Leveraged Leases, Net Equity securities, Gross Unrealized Gains Equity Securities Gross Unrealized Gains Equity securities gross unrealized gains. Total loans serviced for others Mortgage Loans Serviced For Others Mortgage loans serviced for others. Product and Service Product and Service [Axis] Purchases of treasury stock Treasury Stock, Value, Acquired, Cost Method Tier 1 capital to RWA, Well capitalized Banking Regulation, Tier 1 Risk-Based Capital Ratio, Well Capitalized, Minimum 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 Receivable, Deferred Income, Total Unearned discount Loans and Leases Receivable, Deferred Income State and local income taxes, net of federal income tax effect Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Amount Accumulated Amortization Finite-Lived Intangible Assets, Accumulated Amortization Equity Securities [Member] Equity Securities [Member] Subordinated notes due two zero two four. Subordinated Notes Due Two Zero Two Four [Member] 4.00% due 2024 [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. 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Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Other Noncurrent Assets Other assets Amortization of capitalized mortgage servicing rights 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] Period for decreasing the annual rate Defined Benefit Plan Period For Applying Ultimate Health Care Cost Trend Rate Defined benefit plan period for applying ultimate health care cost trend rate. Minimum pension liability Defined Benefit Plans Accumulated Other Comprehensive Income Minimum Pension Liability Before Tax Defined benefit plans accumulated other comprehensive income minimum pension liability before tax. Subordinated Capital Notes [Member] Subordinated Debt [Member] Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, before Tax Accretion of net gain on terminated cash flow hedges Accretion of net gain on terminated cash flow hedges, before tax Brokerage services income Brokerage Commissions Revenue Trading Activity Trading Activity [Axis] Property Plant And Equipment Capitalized Interest Costs [Abstract] Property plant and equipment capitalized interest costs. Other [Member] Other Loans [Member] Other loans. Period of noncancelable operating lease in years Noncancelable Operating Lease Period Noncancelable operating lease period in years. International Activities [Abstract] International activities. Treasury Stock [Member] Treasury Stock, Common [Member] Accounting Changes and Error Corrections [Abstract] CIT [Member] CIT [Member] CIT. Loans Serviced for Others [Member] Loans Serviced for Others [Member] Loans serviced for others. Total deposits Deposits Cash flows from investing activities Net Cash Provided by (Used in) Investing Activities [Abstract] Carrying Amount [Member] Reported Value Measurement [Member] Impact on fair value of 20% adverse change Sensitivity Analysis of Fair Value, Transferor's Interests in Transferred Financial Assets, Impact of 20 Percent Adverse Change in Prepayment Speed 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. Other cost of operations. Other cost of operations Changes in Plan Assets and Benefit Obligations Recognized in Other Comprehensive Income Schedule of Defined Benefit Plan Amounts Recognized in Other Comprehensive Income (Loss) [Table Text Block] PCD acquired loans. PCD Acquired Loans Member PCD Acquired Loans [Member] PCD Derivative [Table] Derivative [Table] Long-term Line of Credit, Total Outstanding borrowings Long-Term Line of Credit Impairment of goodwill Goodwill, Impairment Loss Supplies and Postage Expense, Total Printing, postage and supplies Supplies and Postage Expense Portion at Fair Value Measurement [Member] [Default] Fair Value Disclosure Item Amounts [Default] Portion at Fair Value Measurement [Member] Business combination recognized identifiable assets acquired and liabilities assumed investment securities. Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed Investment securities Investment securities Unallocated [Member] Unallocated Financing Receivables [Member] Long-Lived Tangible Asset Long-Lived Tangible Asset [Domain] Assumed Weighted-Average Rates Used to Determine Net Benefit Expense Assumed Weighted Average Rates Used To Determine Net Benefit Expense Table [Text Block] Assumed weighted-average rates used to determine net benefit expense. Decreases in unrecognized tax benefits as a result of settlements with taxing authorities Decreases in unrecognized tax benefits as a result of settlements with taxing authorities Decreases as a result of settlements with taxing authorities Unrecognized Tax Benefits, Decrease Resulting from Settlements with Taxing Authorities Percent of total loan class at period end Financing receivable modification percent of total loan class Financing receivable modification percent of total loan class. Core deposit and other intangible assets. Core Deposit And Other Intangible Assets Member Core Deposit and Other Intangible Assets [Member] Residential Builder and Developer [Member] Residential Builder And Developer [Member] Residential builder and developer. Commitments to originate real estate loans for sale Commitments To Originate Real Estate Loans For Sale Commitments to originate real estate loans for sale. Preferred stock, liquidation preference per share Preferred Stock, Liquidation Preference Per Share Nonaccrual Loans and Leases Receivable, Nonperforming, Nonaccrual of Interest Depreciation and other amortization Other Depreciation and Amortization Financing: Capital Leases, Net Investment in Direct Financing Leases [Abstract] 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 SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate, Loan Type [Axis] Residential Mortgage-Backed Securities [Member] Residential [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 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] 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] International Equity Securities [Member] Defined Benefit Plan, Equity Securities, Non-US [Member] Weighted-Average Life (In Years), Exercisable Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term 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] Other Private Equity [Member] Private Equity Funds [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] Stock-based compensation plans Share-Based Payment Arrangement [Text Block] Weighted-Average Grant Price, Cancelled Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value Allowance for credit losses Loans and Leases Receivable, Allowance for Loan Losses Policy [Policy Text Block] New borrowings by directors, certain officers and their associates Loans and Leases Receivable, Related Parties, Additions 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 Financing Receivable, Troubled Debt Restructuring, Postmodification Loans and leases, net of unearned discount Financing Receivable, Modified in Period, Amount Repurchase agreements and short term borrowings Short-term borrowings Short-Term Debt 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. Average notional amounts of interest rate swap agreements impacting net interest income, contract entered into for interest rate risk management purposes Average Notional Amount Of Interest Rate Fair Value Hedge Derivatives The average notional amounts of interest rate swap agreement impacting net interest income that were entered into for interest rate risk management purposes. 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. Impaired Financing Receivables [Table Text Block] Summary of Unpaid Principal Balance to Fair Value of Loans and Leases by Portfolio Segment Condensed Balance Sheet Condensed Balance Sheet [Table Text Block] Retirement Plan Type Retirement Plan Type [Axis] Common Equity Tier One Risk Based Capital To Risk Weighted Assets CET1 to RWA, Minimum Ratio Common equity tier one risk based capital divided by risk weighted assets as defined by regulations. Repurchase Agreements [Member] Securities Sold under Agreements to Repurchase [Member] Concentration Risk Type Concentration Risk Type [Domain] Federal Reserve Bank of New York [Member] Federal Reserve Bank Of New York [Member] Federal reserve bank of New York. Trading account Trading Account Trading account. Income Statement Location Income Statement Location [Domain] Weighted-Average Exercise Price, Granted Share-Based Compensation Arrangements by Share-Based Payment Award, Options, Grants in Period, Weighted Average Exercise Price Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification and Tax, Total Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification and Tax Cash flow hedges adjustments 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 (credit) Defined Benefit Plan, Amortization of Prior Service Cost (Credit) Sales-Type and Direct Financing Leases, Payment to be Received, after Year Five Later years Amortization of prior service (cost) credit Amortization of prior service credit, before tax Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), Reclassification Adjustment from AOCI, before Tax Exempt from federal taxes Interest Income, Securities, Operating, Tax Exempt Deposits, Foreign, Total Deposits at Cayman Islands office Deposits at foreign office Deposits at Cayman Islands office Deposits, Foreign Financing Receivable Portfolio Segment Financing Receivable Portfolio Segment [Domain] Summary of Lease Financing Receivables Summary Of Lease Financing Receivables Table [Text Block] Summary of lease financing receivables. Line of credit facility Line of Credit Facility, Current Borrowing Capacity Net cash provided (used) by investing activities Net Cash Provided by (Used in) Investing Activities Asset Pledged as Collateral without Right [Member] Net loss (gain) Defined Benefit Plan, Accumulated Other Comprehensive Income (Loss), Gain (Loss), before Tax Series I Fixed-Rate Reset Non-Cumulative Perpetual Preferred Stock [Member] Series I Fixed Rate Reset Non Cumulative Perpetual Preferred Stock [Member] Series I fixed rate reset non cumulative perpetual preferred stock. Schedule Of Borrowings [Line Items] Schedule Of Borrowings [Line Items] Schedule of borrowings. Variable Rate Due 2021 [Member] Variable Rate Subordinated Notes Due Two Thousand And Twenty One [Member] Variable rate subordinated notes due two thousand and twenty one. Other costs of operations: Other Expenses [Abstract] Goodwill and other intangible assets Goodwill and Intangible Assets Disclosure [Text Block] Income before equity in undistributed income of subsidiaries Income Loss Before Equity In Undistributed Income Of Subsidiaries Income loss before equity in undistributed income of subsidiaries. Real Estate Partnerships [Member] Real estate partnerships. Notional amounts of derivative contracts entered into for trading account purposes Total Notional Amount Derivative, Notional Amount Redemption of Series A and Series C preferred stock Redemption of Series A and C preferred stock Payments for Repurchase of Preferred Stock and Preference Stock Net income available to common shareholders Basic Net Income (Loss) Available to Common Stockholders, Basic Other Deferred Tax Liabilities, Other Quantitative Information Related to Significant Unobservable Inputs Quantitative Information Related To Significant Unobservable Inputs Table [Text Block] Quantitative information related to significant unobservable inputs. Restricted Stock Outstanding, Cancelled Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Forfeited in Period Deferred taxes payable arising from leveraged leases Leveraged Leases, Net Investment in Leveraged Leases Disclosure, Deferred Taxes Arising from Leveraged Leases Net cash provided (used) by financing activities Net Cash Provided by (Used in) Financing Activities Debt Instrument, Redemption, Period Debt Instrument, Redemption, Period [Domain] Defined Benefit Plan, Plan Assets, Category Defined Benefit Plan, Plan Assets, Category [Domain] Financing Receivable Allowance For Credit Losses Other Discount Financing Receivable Allowance For Credit Losses Other Discount Other discount Bayview Financial [Member] Bayview Financial [Member] Bayview Financial. Pledged Status [Axis] Entity Filer Category Entity Filer Category Preferred Stock, Redemption Feature, Redemption Term Preferred Stock Redemption Period After Stock Disqualifies As Tier I Capital Preferred stock redemption period after stock disqualifies as tier I capital. Highest amount at a month-end Short-Term Debt, Maximum Month-end Outstanding Amount Other costs of operations Other Noninterest Expense Supplemental schedule of noncash investing and financing activities Cash Flow, Noncash Investing and Financing Activities Disclosure [Abstract] Loans Sub-serviced for Others [Member] Residential Mortgage Sub Servicing Loan [Member] Sub Servicing Loan [Member] Sub servicing loan. Debt Securities, Held-to-Maturity, Fair Value, Maturity, Allocated and Single Maturity Date, after Year 5 Through 10 Due after five years through ten years Total debt securities Gross unrealized gains Investment In Debt Securities Gross Unrealized Gains Investment in debt securities gross unrealized gains. Weighted-Average Exercise Price, Expired Share-Based Compensation Arrangements by Share-Based Payment Award, Options, Expirations in Period, Weighted Average Exercise Price Balance Sheet Location Balance Sheet Location [Domain] 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. First Maryland Capital I - due 2027 [Member] First Maryland Capital One Variable Rates Due Two Zero Two Seven [Member] First Maryland Capital I variable rates due 2027. Fixed Rate Term Loans 2.10% Due 2020 [Member] Fixed Rate Term Loans Of Senior Notes Due Two Thousand Twenty [Member] Fixed rate term loans of senior notes due two thousand twenty. 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 Geographic Concentration Risk [Member] Geographic Concentration Risk [Member] Net cash used by financing activities Net Cash Provided by (Used in) Financing Activities, Continuing Operations 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 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. 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. Amount Banking Regulation, Total Capital, Actual Defined contribution pension and retirement savings plans total expense Pension and Other Postretirement Benefits Cost (Reversal of Cost), Total Pension and Other Postretirement Benefits Cost (Reversal of Cost) Asset Class Asset Class [Axis] 2026 Defined Benefit Plan, Expected Future Benefit Payment, Year Three Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, after Tax Accretion of net gain on terminated cash flow hedges, net of tax Domestic Mutual Fund Equity Securities [Member] Domestic Mutual Fund Equity Securities [Member] Domestic mutual fund equity securities. Total liabilities Liabilities Derivative Instruments And Hedging Activities Disclosures [Line Items] Derivative Instruments and Hedging Activities Disclosures [Line Items] Other revenues from operations: Component of Operating Income [Abstract] Schedule Of Property Plant And Equipment [Table] Property, Plant and Equipment [Table] Average Maturity (in years) Derivative, Average Remaining Maturity Originations Servicing Asset At Amortized Value Originations Amount of contract to service financial assets originated during the period, under which the benefits of servicing are expected to more than adequately compensate the servicer. Advances from the FHLB latest maturity date, Federal Home Loan Bank, Advances, General Debt Obligations, Disclosures, Due Date, Last Estimated useful lives Finite-Lived Intangible Asset, Useful Life Amortization period Accumulated Other Comprehensive Income Loss [Table] Accumulated Other Comprehensive Income (Loss) [Table] Debt Securities, Held-to-Maturity, Amortized Cost, after Allowance for Credit Loss, Maturity, Allocated and Single Maturity Date, after Year 5 through 10 Due after five years through ten years Series H preferred stocks. Series H Preferred Stocks [Member] Series H Preferred Stock [Member] Recoveries Financing Receivable, Allowance for Credit Loss, Recovery Asset Impairment Charges, Total Asset write-downs Asset Impairment Charges Convertible Preferred Stock Converted to Other Securities Fair value of Preferred stock converted Total shareholders’ equity Shareholders’ equity Beginning balance Ending balance Equity, Attributable to Parent Finance leases net investment in direct financing leases unearned income. Finance Leases Net Investment in Direct Financing Leases Unearned Income Unearned income Commercial and other Commitments To Extend Credit For Commercial And Other Commitments to extend credit for commercial and other. Impact on fair value of 10% adverse change Sensitivity Analysis of Fair Value, Transferor's Interests in Transferred Financial Assets, Impact of 10 Percent Adverse Change in Other Assumption SOFR [Member] Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member] Parent company financial statements Condensed Financial Information of Parent Company Only Disclosure [Text Block] Consolidated Entities Consolidated Entities [Axis] Documents Incorporated by Reference [Text Block] Documents Incorporated by Reference [Text Block] Accrued Interest [Member] Accrued Interest [Member] Accrued interest. Equity and other securities (cost: : $1,125 at December 31, 2023; $934 at December 31, 2022) Equity and other securities, Estimated Fair Value Equity And Other Securities Estimated Fair Value Equity and other securities estimated fair value. Collective Investment Trust. Collective Investment Trust [Member] Transfers and Servicing [Abstract] Net income Net income (loss) Percentage of employer matching contribution to employee's contribution Percentage Of Employee Benefit Plan Expected Contribution By Employer Maximum amount of employer matching contributions to the defined contribution plan for an eligible employee stated as a percentage of the eligible employee's contribution. Defined Benefit Plan, Benefit Obligation, Increase (Decrease) for Plan Amendment Plan amendment Total interest expense Interest Expense Percentage of total assets Defined Benefit Plan Percentage Of Plan Assets The amount of defined benefit pension plan assets that consist of real estate, private equity and other investments, as a percentage of the total defined benefit pension plan assets. Investment securities Interest and Dividend Income, Securities, by Taxable Status [Abstract] Geographic Distribution Geographic Distribution [Axis] Net Periodic Pension Expense for Defined Benefit Plans Schedule of Defined Benefit Plans Disclosures [Table Text Block] Private Equity/Debt [Member] Private Equity Debt [Member] Private equity debt. Trading account Trading Account Policy [Text Block] Trading account. Tax-exempt income Effective Income Tax Rate Reconciliation, Tax Exempt Income, Amount 5.05% fixed/variable due 2034 [Member] Fixed and Variable Rate Five Point Zero Five Percentage Due Two Thousand Thirty Four [Member] Fixed and variable rate five point zero five percentage due two thousand thirty four. Corporate Debt Securities [Member] Corporate Debt Securities [Member] Purchases of investment securities Held to maturity Payments to Acquire Held-to-Maturity Securities Less: Federal, state and local income tax benefits Unrecognized Federal State And Local Income Tax Benefits Net amount of federal, state and local income tax benefit that would be realized if the gross unrecognized tax benefits were to be recognized, including the federal income tax reduction that would result from the payment of the accrued interest on a previously unrecognized tax benefit. This amount reduces the unrecognized tax benefits that, if recognized, would impact the effective income tax rate. Variable Rate Term Loans Due 2022 [Member] Variable Rate Term Loans Due Two Thousand And Twenty Two [Member] Variable rate term loans due two thousand and twenty two. Statement of Financial Position [Abstract] Credit cards Commitments To Extend Credit For Credit Cards Commitments to extend credit for credit cards. Parent Company Only Financial Information [Line Items] Parent Company Only Financial Information [Line Items] Parent Company Only Financial Information [Line Items] 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 Weighted Average Number of Shares Outstanding, Diluted Accumulated benefit obligation Defined Benefit Plan, Accumulated Benefit Obligation Current year benefit plans gains, tax Other Comprehensive (Income) Loss, Defined Benefit Plan, before Reclassification Adjustment, Tax, Total Current year benefit plans gains loss, tax Other Comprehensive (Income) Loss, Defined Benefit Plan, before Reclassification Adjustment, Tax Economic Assumptions Used to Determine Fair Value of Capitalized Servicing Rights and Sensitivity of Value to Changes in Assumptions Schedule of Sensitivity Analysis of Fair Value, Transferor's Interests in Transferred Financial Assets [Table Text Block] Schedule of Income Tax Expense Benefit Reconciliation Schedule of Effective Income Tax Rate Reconciliation [Table Text Block] Credit Facility Credit Facility [Axis] Gain (Loss) on Disposition of Assets for Financial Service Operations, Total Gain (Loss) on Disposition of Assets for Financial Service Operations Net gain on sales of assets Intangible Liability Disclosure [Abstract] Intangible Liability Disclosure [Abstract] Expenses Expenses Total aggregate amount of all interest and noninterest expenses. Commercial letters of credit Commitments Regarding Commercial Letters Of Credit Commitments regarding commercial letters of credit. Other Income and Expenses [Abstract] Other Income and Expenses [Abstract] Federal Deferred Federal Income Tax Expense (Benefit) Offsetting [Abstract] Changes in net unrealized gains (losses) included in earnings related to assets/ instruments still held at end of period 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) Loans receivable Remaining balance of loans and leases Total loans and leases Loans and Leases Receivable, Gross Payments to Acquire Productive Assets, Total Capital expenditures Payments to Acquire Productive Assets Core Deposit and Other Intangible Assets [Member] Core Deposits And Other Intangible Assets [Member] Core deposits and other intangible assets . 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 2026 Lessee, Operating Lease, Liability, to be Paid, Rolling Year Three Other Expenses, Total Other Expenses Interest rate and foreign exchange contracts not designated as hedging instruments Interest rate and foreign exchange contracts not designated as hedging instruments Investment securities available for sale, amortized cost Investment securities, available for sale, amortized cost Debt Securities, Available-for-Sale, Amortized Cost Weighted-average remaining lease term Operating Lease, Weighted Average Remaining Lease Term Amortization of investments in qualified affordable housing projects Amortization Method Qualified Affordable Housing Project Investments, Amortization Defined contribution pension plan expense Net periodic pension (benefit) cost Defined Benefit Plan, Net Periodic Benefit Cost (Credit) Target allocations for plan assets Defined Benefit Plan, Plan Assets, Target Allocation, Percentage Servicing Asset At Amortized Value Additional Disclosures [Abstract] Servicing Asset At Amortized Value Additional Disclosures [Abstract] Income tax benefit recognition criteria percentage threshold Income Tax Benefit Recognition Criteria Percentage Threshold The percentage threshold of the likelihood of an uncertain tax position being realized upon ultimate settlement for recognition of the benefit. Income taxes Income Tax Disclosure [Text Block] Assets Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets Total identifiable assets acquired Total income Income Loss Before Expenses And Tax Credits Attributable To Parent Reflects the sum of all revenue and income (prior to any tax credits) recognized by the entity in the period, including dividends from consolidated bank subsidiaries, the entity's proportionate share for the period of the net income (loss) of its investee (such as unconsolidated subsidiaries and joint ventures) to which the equity method of accounting is applied, and all other revenue and income recognized by the entity. Institutional Services and Wealth Management [ Member] Institutional Services and Wealth Management [ Member] Maximum employer contribution on Employee's qualified contribution Maximum Employer Contribution On Employees Qualified Contribution Maximum amount of employer matching contributions to the defined contribution plan for an eligible employee stated as a percentage of the eligible employee's qualified compensation. Weighted-Average Exercise Price, Outstanding, Beginning balance Weighted-Average Exercise Price, Outstanding, Ending balance Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Weighted Average Exercise Price Preferred stock cash dividends Dividends, Preferred Stock, Cash Finite-Lived Intangible Assets [Line Items] Finite-Lived Intangible Assets [Line Items] Non-U.S. Government [Member] Debt Security, Government, Non-US [Member] Common stock issuable, shares Common Stock Issuable Share Number of shares of common stock issuable in connection with deferred compensation plans. Payment Deferral [Member] Loan Restructuring Modification [Axis] Valuation Approach and Technique Valuation Approach and Technique [Axis] Disaggregation Of Revenue [Line Items] Disaggregation of Revenue [Line Items] Fair value of Purchased loans and leases. Fair value of Purchased loans and leases Fair value Valuation Allowance for Impairment of Recognized Servicing Assets, Additions (Deductions) for Expenses (Recoveries), Total Valuation Charge Recognized Valuation Allowance for Impairment of Recognized Servicing Assets, Additions (Deductions) for Expenses (Recoveries) 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 speeds Assumption for Fair Value of Assets or Liabilities that relate to Transferor's Continuing Involvement, Prepayment Speed Capital Ratios and Amounts of Company and its Banking Subsidiaries Schedule of Compliance with Regulatory Capital Requirements under Banking Regulations [Table Text Block] Income Tax Authority Income Tax Authority [Axis] 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. Stockholders Equity Excluding Portion Attributable To Subsidiaries Noncontrolling Interest [Abstract] Stockholders Equity Excluding Portion Attributable To Subsidiaries Noncontrolling Interest [Abstract] Fair Value Disclosures [Abstract] Shares issuable under deferred compensation plans Deferred Compensation Arrangement with Individual, Shares Authorized for Issuance Total current Current Income Tax Expense (Benefit) Initial estimate of expected credit losses. Initial Estimate Of Expected Credit Losses Initial estimate of expected credit losses Furniture and equipment Furniture and Fixtures, Gross Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] Fair Value Hierarchy and NAV [Axis] Measurement Frequency Measurement Frequency [Domain] Statement of Partners' Capital [Abstract] Repurchase Agreements Securities Sold under Agreements to Repurchase Fixed Rate Term Loans 4.70% due 2028 [Member] Fixed Rate Term Loans Of Four Point Seven Zero Senior Notes Due Two Thousand Twenty Eight [Member] Fixed rate term loans of four point seven zero senior notes due two thousand twenty eight. Hedging Designation Hedging Designation [Axis] Equipment and net occupancy Occupancy, Net Professional and other services Professional and Contract Services Expense Geographic Distribution, Foreign [Member] Geographic Distribution, Foreign [Member] Reclassifications Reclassification, Comparability Adjustment [Policy Text Block] Revision of Prior Period Revision of Prior Period [Domain] Restricted Stock Outstanding, Vested Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Vested in Period Discount rates for fair value estimations Measurement Input Adjustments Measurement input adjustments. Delinquent period of loans secured by real estate resulting in charge off Delinquent Period Of Loans Secured By Real Estate Resulting In Charge Off Period of time that a delinquent loan secured by real estate will result in the excess of the loan balance over the net realizable value of the property collateralizing the loan is charged off. Other Assets and Other Liabilities [Member] Other Assets And Other Liabilities [Member] Other assets and other liabilities. Accrued liability recognized in the Consolidated Balance Sheet Liability, Defined Benefit Plan, Total Liability, Defined Benefit Plan Business Acquisition Business Acquisition [Axis] Interest Expense, Long-term Debt, Total Interest on long-term borrowings Long-term borrowings Interest Expense, Long-Term Debt Changes to goodwill assigned to reporting unit Goodwill, Period Increase (Decrease), Total Goodwill, Period Increase (Decrease) Decrease in goodwill Long Term Fixed Rate Advances From Fhlb Long Term Fixed Rate Advances From Fhlb [Member] Long-term fixed rate advances from the FHLB. Loans and Leases Receivable, Allowance, Total Allowance for credit losses Beginning balance Ending balance Loans and Leases Receivable, Allowance Income Tax Disclosure [Abstract] 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 Finite-Lived Intangible Assets by Major Class [Axis] Commercial, Financial, Leasing, etc. [Member] Commercial Financial Leasing [Member] Commercial financial leasing. Included in other comprehensive income Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss) Cash Flow Hedges [Member] Cash Flow Hedging [Member] Defined Benefit Plan, Funded (Unfunded) Status of Plan, Total Funded status Defined Benefit Plan, Funded (Unfunded) Status of Plan Net gain Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss) Arising During Period, before Tax