XML 58 R65.htm IDEA: XBRL DOCUMENT v2.4.1.9
Derivative Financial Instruments - Information about Fair Values of Derivative Instruments in Consolidated Balance Sheet (Detail) (USD $)
In Thousands, unless otherwise specified
Mar. 31, 2015
Dec. 31, 2014
Derivatives, Fair Value [Line Items]    
Asset derivatives, Fair value $ 386,159us-gaap_DerivativeFairValueOfDerivativeAsset $ 338,855us-gaap_DerivativeFairValueOfDerivativeAsset
Liability derivatives, Fair value 252,314us-gaap_DerivativeFairValueOfDerivativeLiability 212,059us-gaap_DerivativeFairValueOfDerivativeLiability
Derivatives Not Designated and Qualifying as Hedging Instruments [Member]    
Derivatives, Fair Value [Line Items]    
Asset derivatives, Fair value 312,642us-gaap_DerivativeFairValueOfDerivativeAsset
/ us-gaap_HedgingDesignationAxis
= us-gaap_NondesignatedMember		 264,876us-gaap_DerivativeFairValueOfDerivativeAsset
/ us-gaap_HedgingDesignationAxis
= us-gaap_NondesignatedMember
Liability derivatives, Fair value 248,785us-gaap_DerivativeFairValueOfDerivativeLiability
/ us-gaap_HedgingDesignationAxis
= us-gaap_NondesignatedMember		 207,842us-gaap_DerivativeFairValueOfDerivativeLiability
/ us-gaap_HedgingDesignationAxis
= us-gaap_NondesignatedMember
Fair Value Hedges [Member] | Derivatives Designated and Qualifying as Hedging Instruments [Member]    
Derivatives, Fair Value [Line Items]    
Asset derivatives, Fair value 73,517us-gaap_DerivativeFairValueOfDerivativeAsset
/ us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis
= us-gaap_FairValueHedgingMember
/ us-gaap_HedgingDesignationAxis
= us-gaap_DesignatedAsHedgingInstrumentMember		 73,979us-gaap_DerivativeFairValueOfDerivativeAsset
/ us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis
= us-gaap_FairValueHedgingMember
/ us-gaap_HedgingDesignationAxis
= us-gaap_DesignatedAsHedgingInstrumentMember
Liability derivatives, Fair value 3,529us-gaap_DerivativeFairValueOfDerivativeLiability
/ us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis
= us-gaap_FairValueHedgingMember
/ us-gaap_HedgingDesignationAxis
= us-gaap_DesignatedAsHedgingInstrumentMember		 4,217us-gaap_DerivativeFairValueOfDerivativeLiability
/ us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis
= us-gaap_FairValueHedgingMember
/ us-gaap_HedgingDesignationAxis
= us-gaap_DesignatedAsHedgingInstrumentMember
Interest Rate Swap Agreements [Member] | Fair Value Hedges [Member] | Derivatives Designated and Qualifying as Hedging Instruments [Member]    
Derivatives, Fair Value [Line Items]    
Asset derivatives, Fair value 72,855us-gaap_DerivativeFairValueOfDerivativeAsset
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_InterestRateSwapMember
/ us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis
= us-gaap_FairValueHedgingMember
/ us-gaap_HedgingDesignationAxis
= us-gaap_DesignatedAsHedgingInstrumentMember		 73,251us-gaap_DerivativeFairValueOfDerivativeAsset
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_InterestRateSwapMember
/ us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis
= us-gaap_FairValueHedgingMember
/ us-gaap_HedgingDesignationAxis
= us-gaap_DesignatedAsHedgingInstrumentMember
Commitments to Sell Real Estate Loans [Member] | Derivatives Not Designated and Qualifying as Hedging Instruments [Member]    
Derivatives, Fair Value [Line Items]    
Asset derivatives, Fair value 1,571us-gaap_DerivativeFairValueOfDerivativeAsset
/ us-gaap_DerivativeInstrumentRiskAxis
= mtb_CommitmentsToSellRealEstateLoansMember
/ us-gaap_HedgingDesignationAxis
= us-gaap_NondesignatedMember		 754us-gaap_DerivativeFairValueOfDerivativeAsset
/ us-gaap_DerivativeInstrumentRiskAxis
= mtb_CommitmentsToSellRealEstateLoansMember
/ us-gaap_HedgingDesignationAxis
= us-gaap_NondesignatedMember
Liability derivatives, Fair value 8,552us-gaap_DerivativeFairValueOfDerivativeLiability
/ us-gaap_DerivativeInstrumentRiskAxis
= mtb_CommitmentsToSellRealEstateLoansMember
/ us-gaap_HedgingDesignationAxis
= us-gaap_NondesignatedMember		 4,330us-gaap_DerivativeFairValueOfDerivativeLiability
/ us-gaap_DerivativeInstrumentRiskAxis
= mtb_CommitmentsToSellRealEstateLoansMember
/ us-gaap_HedgingDesignationAxis
= us-gaap_NondesignatedMember
Commitments to Sell Real Estate Loans [Member] | Fair Value Hedges [Member] | Derivatives Designated and Qualifying as Hedging Instruments [Member]    
Derivatives, Fair Value [Line Items]    
Asset derivatives, Fair value 662us-gaap_DerivativeFairValueOfDerivativeAsset
/ us-gaap_DerivativeInstrumentRiskAxis
= mtb_CommitmentsToSellRealEstateLoansMember
/ us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis
= us-gaap_FairValueHedgingMember
/ us-gaap_HedgingDesignationAxis
= us-gaap_DesignatedAsHedgingInstrumentMember		 728us-gaap_DerivativeFairValueOfDerivativeAsset
/ us-gaap_DerivativeInstrumentRiskAxis
= mtb_CommitmentsToSellRealEstateLoansMember
/ us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis
= us-gaap_FairValueHedgingMember
/ us-gaap_HedgingDesignationAxis
= us-gaap_DesignatedAsHedgingInstrumentMember
Liability derivatives, Fair value 3,529us-gaap_DerivativeFairValueOfDerivativeLiability
/ us-gaap_DerivativeInstrumentRiskAxis
= mtb_CommitmentsToSellRealEstateLoansMember
/ us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis
= us-gaap_FairValueHedgingMember
/ us-gaap_HedgingDesignationAxis
= us-gaap_DesignatedAsHedgingInstrumentMember		 4,217us-gaap_DerivativeFairValueOfDerivativeLiability
/ us-gaap_DerivativeInstrumentRiskAxis
= mtb_CommitmentsToSellRealEstateLoansMember
/ us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis
= us-gaap_FairValueHedgingMember
/ us-gaap_HedgingDesignationAxis
= us-gaap_DesignatedAsHedgingInstrumentMember
Mortgage-Related Commitments to Originate Real Estate Loans for Sale [Member] | Derivatives Not Designated and Qualifying as Hedging Instruments [Member]    
Derivatives, Fair Value [Line Items]    
Asset derivatives, Fair value 26,295us-gaap_DerivativeFairValueOfDerivativeAsset
/ us-gaap_DerivativeInstrumentRiskAxis
= mtb_MortgageRelatedCommitmentsToOriginateRealEstateLoansForSaleMember
/ us-gaap_HedgingDesignationAxis
= us-gaap_NondesignatedMember		 17,396us-gaap_DerivativeFairValueOfDerivativeAsset
/ us-gaap_DerivativeInstrumentRiskAxis
= mtb_MortgageRelatedCommitmentsToOriginateRealEstateLoansForSaleMember
/ us-gaap_HedgingDesignationAxis
= us-gaap_NondesignatedMember
Liability derivatives, Fair value 65us-gaap_DerivativeFairValueOfDerivativeLiability
/ us-gaap_DerivativeInstrumentRiskAxis
= mtb_MortgageRelatedCommitmentsToOriginateRealEstateLoansForSaleMember
/ us-gaap_HedgingDesignationAxis
= us-gaap_NondesignatedMember		 49us-gaap_DerivativeFairValueOfDerivativeLiability
/ us-gaap_DerivativeInstrumentRiskAxis
= mtb_MortgageRelatedCommitmentsToOriginateRealEstateLoansForSaleMember
/ us-gaap_HedgingDesignationAxis
= us-gaap_NondesignatedMember
Interest Rate Contracts [Member] | Derivatives Not Designated and Qualifying as Hedging Instruments [Member]    
Derivatives, Fair Value [Line Items]    
Asset derivatives, Fair value 246,819us-gaap_DerivativeFairValueOfDerivativeAsset
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_InterestRateContractMember
/ us-gaap_HedgingDesignationAxis
= us-gaap_NondesignatedMember		 215,614us-gaap_DerivativeFairValueOfDerivativeAsset
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_InterestRateContractMember
/ us-gaap_HedgingDesignationAxis
= us-gaap_NondesignatedMember
Liability derivatives, Fair value 204,484us-gaap_DerivativeFairValueOfDerivativeLiability
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_InterestRateContractMember
/ us-gaap_HedgingDesignationAxis
= us-gaap_NondesignatedMember		 173,513us-gaap_DerivativeFairValueOfDerivativeLiability
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_InterestRateContractMember
/ us-gaap_HedgingDesignationAxis
= us-gaap_NondesignatedMember
Foreign Exchange and Other Option and Futures Contracts [Member] | Derivatives Not Designated and Qualifying as Hedging Instruments [Member]    
Derivatives, Fair Value [Line Items]    
Asset derivatives, Fair value 37,957us-gaap_DerivativeFairValueOfDerivativeAsset
/ us-gaap_DerivativeInstrumentRiskAxis
= mtb_ForeignExchangeAndOtherOptionAndFuturesContractsMember
/ us-gaap_HedgingDesignationAxis
= us-gaap_NondesignatedMember		 31,112us-gaap_DerivativeFairValueOfDerivativeAsset
/ us-gaap_DerivativeInstrumentRiskAxis
= mtb_ForeignExchangeAndOtherOptionAndFuturesContractsMember
/ us-gaap_HedgingDesignationAxis
= us-gaap_NondesignatedMember
Liability derivatives, Fair value $ 35,684us-gaap_DerivativeFairValueOfDerivativeLiability
/ us-gaap_DerivativeInstrumentRiskAxis
= mtb_ForeignExchangeAndOtherOptionAndFuturesContractsMember
/ us-gaap_HedgingDesignationAxis
= us-gaap_NondesignatedMember		 $ 29,950us-gaap_DerivativeFairValueOfDerivativeLiability
/ us-gaap_DerivativeInstrumentRiskAxis
= mtb_ForeignExchangeAndOtherOptionAndFuturesContractsMember
/ us-gaap_HedgingDesignationAxis
= us-gaap_NondesignatedMember