XML 100 R75.htm IDEA: XBRL DOCUMENT
v3.25.0.1

Significant Group Concentrations of Credit Risk Significant Group Concentrations of Credit Risk (Commercial Real Estate Exposure) (Details) - USD ($) $ in Millions | Dec. 31, 2024 | Dec. 31, 2023
--- | --- | ---
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Concentration Risk Threshold - Commercial Real Estate | 36.00% |
Current loans | $ 49,968 | $ 51,717
Real estate construction loans |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Current loans | 3,680 | 5,083
Commercial mortgage loans |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Current loans | 14,493 | 13,686
Total commercial real estate |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Current loans | 18,173 | 18,769
Total unused commitments | 3,130 | 4,382
Commercial Real Estate business line | Real estate construction loans |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Current loans | 3,358 | 4,570
Commercial Real Estate business line | Commercial mortgage loans |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Current loans | 6,044 | 4,727
Other Business Lines Member | Real estate construction loans |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Current loans | 322 | 513
Other Business Lines Member | Commercial mortgage loans |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Current loans | $ 8,449 | $ 8,959

X
- Definition Concentration Risk Threshold - Commercial Real Estate + References No definition available. + Details
Name: | cma_ConcentrationRiskThresholdCommercialRealEstate
Namespace Prefix: | cma_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Current loans + References No definition available. + Details
Name: | cma_CurrentLoans
Namespace Prefix: | cma_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Reflects unused commitments that have been issued to businesses to acquire real property, develop land for sale or construction thereon, to construct a facility and to provide financing on existing land or a building, which, pursuant to terms of the underlying debt instrument, are secured at a minimum but possibly exclusively by that real property. + References No definition available. + Details
Name: | cma_LoansReceivableUnusedCommitment
Namespace Prefix: | cma_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

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/2009/role/commonPracticeRef -Topic 310 -SubTopic 20 -Name Accounting Standards Codification -Section 40 -Paragraph 7 -Publisher FASB -URI https://asc.fasb.org/1943274/2147481628/310-20-40-7 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 310 -SubTopic 10 -Name Accounting Standards Codification -Section 45 -Paragraph 2 -Publisher FASB -URI https://asc.fasb.org/1943274/2147481990/310-10-45-2 + Details
Name: | us-gaap_AccountsNotesAndLoansReceivableLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_ConstructionLoansMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_RealEstateLoanMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_CommercialRealEstateMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | cma_CommercialRealEstateLineOfBusinessClassificationAxis=cma_CommercialRealEstateBusinessLineMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | cma_CommercialRealEstateLineOfBusinessClassificationAxis=cma_OtherBusinessLineMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |