XML 144 R125.htm IDEA: XBRL DOCUMENT
v3.25.0.1

Derivative Financial Instruments - Additional Information (Detail) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2024 | Dec. 31, 2023 | Dec. 31, 2022
Derivative [Line Items] |  |  |
Notional amounts of derivative contracts entered into for trading account purposes | $ 36,184 | $ 26,977 |
Reduction in estimated fair value of interest rate contracts in asset position | (686) | (783) |
Reduction in estimated fair value of interest rate contracts in liability position | (15) | (32) |
Unrealized gain recognized in other comprehensive income related to cash flow hedges | 135 |  |
Aggregate fair value of derivative financial instruments in asset position | 157 | 179 |
Collateral relating to net asset positions | 157 | 179 |
Fair Value Hedges |  |  |
Derivative [Line Items] |  |  |
Impact of estimated fair value gain (losses) on hedging instruments | 153 | 43 |
Cash Flow Hedges |  |  |
Derivative [Line Items] |  |  |
Impact of estimated fair value gain (losses) on hedging instruments | 136 | 214 |
Clearinghouse Credit Facilities |  |  |
Derivative [Line Items] |  |  |
Amount of initial margin posted | 257 | 129 |
Interest rate swap agreements |  |  |
Derivative [Line Items] |  |  |
Increase decrease in net interest income due to interest rate swap agreements | (414) | $ (302) | $ (26)
Notional amounts of derivative contracts entered into for trading account purposes | $ 36,184 |  |
Derivative Instrument, Gain (Loss) Reclassified from AOCI into Income, Effective Portion, Statement of Income or Comprehensive Income [Extensible Enumeration] | Interest and Dividend Income, Operating | Interest and Dividend Income, Operating | Interest and Dividend Income, Operating
Interest rate swap agreements | 2025 |  |  |
Derivative [Line Items] |  |  |
Unrealized gain recognized in other comprehensive income related to cash flow hedges | $ (47) |  |
Interest rate swap agreements | 2026 |  |  |
Derivative [Line Items] |  |  |
Unrealized gain recognized in other comprehensive income related to cash flow hedges | (49) |  |
Interest rate swap agreements | 2027 |  |  |
Derivative [Line Items] |  |  |
Unrealized gain recognized in other comprehensive income related to cash flow hedges | 6 |  |
Interest rate swap agreements | 2028 |  |  |
Derivative [Line Items] |  |  |
Unrealized gain recognized in other comprehensive income related to cash flow hedges | (45) |  |
Cash Flow Hedges |  |  |
Derivative [Line Items] |  |  |
Increase decrease in net interest income due to interest rate swap agreements | (364) | $ (250) | $ (36)
Interest Rate Contracts |  |  |
Derivative [Line Items] |  |  |
Notional amounts of derivative contracts entered into for trading account purposes | 40,500 | 44,400 |
Foreign Currency and Other Option and Futures Contracts |  |  |
Derivative [Line Items] |  |  |
Notional amounts of derivative contracts entered into for trading account purposes | 1,600 | 1,500 |
Forward-Starting Interest Rate Swap Agreements | Fair Value Hedges |  |  |
Derivative [Line Items] |  |  |
Notional amounts of derivative contracts entered into for trading account purposes | 3,400 | 1,000 |
Forward-Starting Interest Rate Swap Agreements | Cash Flow Hedges |  |  |
Derivative [Line Items] |  |  |
Notional amounts of derivative contracts entered into for trading account purposes | $ 10,000 | $ 9,000 |

X
- Definition Impact In Estimated Fair Value Gain Losses On Hedging Instruments + References No definition available. + Details
Name: | mtb_ImpactInEstimatedFairValueGainLossesOnHedgingInstruments
Namespace Prefix: | mtb_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition IncreaseDecreaseInEstimatedFairValueOfInterestRateContractsInAssetPosition + References No definition available. + Details
Name: | mtb_IncreaseDecreaseInEstimatedFairValueOfInterestRateContractsInAssetPosition
Namespace Prefix: | mtb_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition IncreaseDecreaseInEstimatedFairValueOfInterestRateContractsInLiabilityPosition + References No definition available. + Details
Name: | mtb_IncreaseDecreaseInEstimatedFairValueOfInterestRateContractsInLiabilityPosition
Namespace Prefix: | mtb_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The aggregate fair value of assets that are already posted, at the end of the reporting period, as collateral for derivative instruments with credit-risk-related contingent features. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4H -Subparagraph (d) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480434/815-10-50-4H + Details
Name: | us-gaap_CollateralAlreadyPostedAggregateFairValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Fair value of securities received as collateral against derivative assets. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 210 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 12 -Publisher FASB -URI https://asc.fasb.org/1943274/2147483444/210-20-55-12 + Details
Name: | us-gaap_DerivativeAssetFairValueOfCollateral
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Fair value, after offset of derivative liability, of financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset, before offset against an obligation to return collateral under a master netting arrangement. Includes assets elected not to be offset. Excludes assets not subject to a master netting arrangement. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Section 55 -Paragraph 9 -SubTopic 20 -Topic 210 -Publisher FASB -URI https://asc.fasb.org/1943274/2147483444/210-20-55-9 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (c) -SubTopic 20 -Topic 210 -Publisher FASB -URI https://asc.fasb.org/1943274/2147483466/210-20-50-3 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Section 55 -Paragraph 10 -SubTopic 20 -Topic 210 -Publisher FASB -URI https://asc.fasb.org/1943274/2147483444/210-20-55-10 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 8 -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480434/815-10-50-8 + Details
Name: | us-gaap_DerivativeFairValueOfDerivativeAssetAmountNotOffsetAgainstCollateral
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Indicates line item in statement of income or comprehensive income that includes gain (loss) from effective portion of derivative instrument reclassified from accumulated other comprehensive income (AOCI) into income. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 815 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 4D -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480434/815-10-50-4D + Details
Name: | us-gaap_DerivativeInstrumentGainLossReclassifiedFromAociIntoIncomeEffectivePortionStatementOfIncomeOrComprehensiveIncomeExtensibleEnumeration
Namespace Prefix: | us-gaap_
Data Type: | enum2:enumerationSetItemType
Balance Type: | na
Period Type: | duration

X
- Definition The effective portion of net gain (loss) reclassified from accumulated other comprehensive income into income on derivative instruments designated and qualifying as hedging instruments. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Section 50 -Paragraph 4D -Subparagraph (b) -SubTopic 10 -Topic 815 -Publisher FASB -URI https://asc.fasb.org/1943274/2147480434/815-10-50-4D Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 815 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 4C -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480434/815-10-50-4C + Details
Name: | us-gaap_DerivativeInstrumentsGainLossReclassifiedFromAccumulatedOCIIntoIncomeEffectivePortionNet
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 815 -SubTopic 40 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (f) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480237/815-40-50-5 + Details
Name: | us-gaap_DerivativeLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Nominal or face amount used to calculate payment on derivative. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 815 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 1B -Publisher FASB -URI https://asc.fasb.org/1943274/2147480434/815-10-50-1B Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 815 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 1A -Subparagraph (d) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480434/815-10-50-1A + Details
Name: | us-gaap_DerivativeNotionalAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | na
Period Type: | instant

X
- Definition Amount of unrealized gain (loss) related to the increase or decrease in fair value of interest rate derivatives designated as cash flow hedging instruments, which was recorded in accumulated other comprehensive income to the extent that the cash flow hedge was determined to be effective. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 815 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 4C -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480434/815-10-50-4C + Details
Name: | us-gaap_UnrealizedGainLossOnInterestRateCashFlowHedgesPretaxAccumulatedOtherComprehensiveIncomeLoss
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Details
Name: | us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis=us-gaap_FairValueHedgingMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis=us-gaap_CashFlowHedgingMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=mtb_ClearinghouseCreditFacilitiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=us-gaap_InterestRateSwapMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentRedemptionPeriodAxis=mtb_MaturityPeriodOneMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentRedemptionPeriodAxis=mtb_MaturityPeriodTwoMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentRedemptionPeriodAxis=mtb_MaturityPeriodThreeMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentRedemptionPeriodAxis=mtb_MaturityPeriodFourMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=us-gaap_CashFlowHedgingMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=us-gaap_InterestRateContractMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=mtb_ForeignCurrencyAndOtherOptionAndFuturesContractsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=mtb_ForwardStartingInterestRateSwapAgreementsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |