Name:	mtb_DerivativeNotionalAmountToExpireInNextTwelveMonths
Namespace Prefix:	mtb_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	instant

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.

No definition available.

Name:	mtb_DerivativeNotionalAmountToExpireInYearSix
Namespace Prefix:	mtb_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	instant

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.

No definition available.

Name:	mtb_DerivativeNotionalAmountToExpireInYearTwo
Namespace Prefix:	mtb_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	instant

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.

No definition available.

Name:	us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Nominal or face amount used to calculate payment on derivative.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1B
-URI http://asc.fasb.org/extlink&oid=125515794&loc=SL5580258-113959

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1A
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=125515794&loc=SL5579245-113959