XML 106 R87.htm IDEA: XBRL DOCUMENT
v3.25.0.1

Capitalized Servicing Assets - Changes in Capitalized Servicing Assets (Detail) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2024 | Dec. 31, 2023 | Dec. 31, 2022
Residential Mortgage Loans |  |  |
Servicing Asset at Amortized Cost [Line Items] |  |  |
Beginning balance | $ 456 | $ 194 | $ 241
Originations | 20 | 13 | 7
Purchases | 0 | 350 | 0
Acquired in business combination | 0 | 0 | 12
Amortization | (108) | (101) | (66)
Ending balance | 368 | 456 | 194
Valuation allowance | 0 | 0 | 0
Ending balance, net | 368 | 456 | 194
Total loans serviced for others | 149,649 | 155,342 |
Residential Mortgage Loans | Loans serviced for others |  |  |
Servicing Asset at Amortized Cost [Line Items] |  |  |
Total loans serviced for others | 38,105 | 40,021 |
Residential Mortgage Loans | Loans sub-serviced for others |  |  |
Servicing Asset at Amortized Cost [Line Items] |  |  |
Total loans serviced for others | 111,544 | 115,321 |
Commercial Mortgage Loans |  |  |
Servicing Asset at Amortized Cost [Line Items] |  |  |
Beginning balance | 123 | 126 | 133
Originations | 34 | 27 | 24
Purchases | 0 | 0 | 0
Acquired in business combination | 0 | 0 | 0
Amortization | (31) | (30) | (31)
Ending balance | 126 | 123 | 126
Valuation allowance | 0 | 0 | 0
Ending balance, net | 126 | 123 | $ 126
Total loans serviced for others | 31,537 | 28,030 |
Commercial Mortgage Loans | Loans serviced for others |  |  |
Servicing Asset at Amortized Cost [Line Items] |  |  |
Total loans serviced for others | 27,474 | 24,157 |
Commercial Mortgage Loans | Loans sub-serviced for others |  |  |
Servicing Asset at Amortized Cost [Line Items] |  |  |
Total loans serviced for others | $ 4,063 | $ 3,873 |

X
- Definition Mortgage Loans Serviced For Others + References No definition available. + Details
Name: | mtb_MortgageLoansServicedForOthers
Namespace Prefix: | mtb_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Service Asset At Amortized Value Acquired In Business Combination + References No definition available. + Details
Name: | mtb_ServiceAssetAtAmortizedValueAcquiredInBusinessCombination
Namespace Prefix: | mtb_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Servicing Asset At Amortized Value Originations + References No definition available. + Details
Name: | mtb_ServicingAssetAtAmortizedValueOriginations
Namespace Prefix: | mtb_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amortized amount of contract to service financial assets under which the benefits of servicing are expected to more than adequately compensate the servicer. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 860 -SubTopic 50 -Name Accounting Standards Codification -Section 50 -Paragraph 4 -Subparagraph (a)(1) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481229/860-50-50-4 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 860 -SubTopic 50 -Name Accounting Standards Codification -Section 45 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org/1943274/2147481260/860-50-45-1 Reference 3: http://www.xbrl.org/2003/role/recommendedDisclosureRef -Topic 860 -SubTopic 50 -Name Accounting Standards Codification -Section 45 -Paragraph 2 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481260/860-50-45-2 + Details
Name: | us-gaap_ServicingAssetAtAmortizedValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of additions from purchases, assumption or transfer to contract to service financial assets under which the benefits of servicing are expected to more than adequately compensate the servicer. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 860 -SubTopic 50 -Name Accounting Standards Codification -Section 50 -Paragraph 4 -Subparagraph (a)(2) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481229/860-50-50-4 + Details
Name: | us-gaap_ServicingAssetAtAmortizedValueAdditions
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of amortization of contract to service financial assets under which the benefits of servicing are expected to more than adequately compensate the servicer. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 860 -SubTopic 50 -Name Accounting Standards Codification -Section 50 -Paragraph 4 -Subparagraph (a)(4) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481229/860-50-50-4 + Details
Name: | us-gaap_ServicingAssetAtAmortizedValueAmortization1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Fair value of contract to service financial assets under which the benefits of servicing are expected to more than adequately compensate the servicer. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 860 -SubTopic 50 -Name Accounting Standards Codification -Section 50 -Paragraph 4 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481229/860-50-50-4 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 815 -SubTopic 20 -Section 50 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org/1943274/2147480591/815-20-50-1 + Details
Name: | us-gaap_ServicingAssetAtAmortizedValueFairValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of increase (decrease) in the amortized amount from a decrease (increase) in the valuation allowance applied to the servicing asset for a contract to service financial assets under which the benefits of servicing are expected to more than adequately compensate the servicer. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 860 -SubTopic 50 -Name Accounting Standards Codification -Section 50 -Paragraph 4 -Subparagraph (a)(5) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481229/860-50-50-4 + Details
Name: | us-gaap_ServicingAssetAtAmortizedValueValuationAllowance
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
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 860 -SubTopic 50 -Name Accounting Standards Codification -Section 50 -Paragraph 4 -Subparagraph (a)(1) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481229/860-50-50-4 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 860 -SubTopic 50 -Name Accounting Standards Codification -Section 50 -Paragraph 4 -Subparagraph (a)(2) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481229/860-50-50-4 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 860 -SubTopic 50 -Name Accounting Standards Codification -Section 50 -Paragraph 4 -Subparagraph (a)(3) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481229/860-50-50-4 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Topic 860 -SubTopic 50 -Name Accounting Standards Codification -Section 50 -Paragraph 4 -Subparagraph (a)(4) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481229/860-50-50-4 Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Topic 860 -SubTopic 50 -Name Accounting Standards Codification -Section 50 -Paragraph 4 -Subparagraph (a)(5) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481229/860-50-50-4 Reference 6: http://www.xbrl.org/2003/role/disclosureRef -Topic 860 -SubTopic 50 -Name Accounting Standards Codification -Section 50 -Paragraph 4 -Subparagraph (a)(6) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481229/860-50-50-4 Reference 7: http://www.xbrl.org/2003/role/disclosureRef -Topic 860 -SubTopic 50 -Name Accounting Standards Codification -Section 50 -Paragraph 4 -Subparagraph (a)(7) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481229/860-50-50-4 + Details
Name: | us-gaap_ServicingAssetsAtAmortizedValueLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

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

X
- Details
Name: | us-gaap_ClassOfFinancingReceivableTypeOfBorrowerAxis=mtb_LoansServicedForOthersMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ClassOfFinancingReceivableTypeOfBorrowerAxis=mtb_SubServicingLoanMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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