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v3.24.3

Segment Information - Additional Information (Details) - USD ($) | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2024 | Sep. 30, 2023 | Sep. 30, 2024 | Sep. 30, 2023
Segment Reporting [Abstract] |  |  |  |
Taxable-equivalent adjustment | $ 13,000,000 | $ 15,000,000 | $ 38,000,000 | $ 41,000,000

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

X
- References No definition available. + Details
Name: | us-gaap_SegmentReportingAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration