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

Derivative notional amount to expire in year five.

No definition available.

Name:	mtb_DerivativeNotionalAmountToExpireInYearFive
Namespace Prefix:	mtb_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Derivative notional amount to expire in year four.

No definition available.

Name:	mtb_DerivativeNotionalAmountToExpireInYearFour
Namespace Prefix:	mtb_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Derivative notional amount to expire in year ten.

No definition available.

Name:	mtb_DerivativeNotionalAmountToExpireInYearTen
Namespace Prefix:	mtb_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Derivative notional amount to expire in year three.

No definition available.

Name:	mtb_DerivativeNotionalAmountToExpireInYearThree
Namespace Prefix:	mtb_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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
-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