XML 100 R82.htm IDEA: XBRL DOCUMENT v3.22.0.1

Significant Group Concentrations of Credit Risk Significant Group Concentrations of Credit Risk (Schedule of Automotive Industry Outstanding Loans and Total Exposure) (Details) - USD ($) $ in Millions		Dec. 31, 2021	Dec. 31, 2020
Concentration Risk [Line Items]
Total automotive loans		$ 5,274	$ 6,785
Total automotive exposure		12,706	11,920
Automotive Production
Concentration Risk [Line Items]
Total automotive loans	[1]	1,112	1,093
Total automotive exposure	[1]	2,041	2,267
Automotive Dealer
Concentration Risk [Line Items]
Total automotive loans		4,162	5,692
Total automotive exposure		$ 10,665	$ 9,653
[1] Excludes PPP loans.

X

- Definition

Total automotive exposure including loans and other credit commitments to automotive dealers and to borrowers involved with automotive production.

+ References

No definition available.

+ Details

Name:	cma_TotalAutomotiveExposure
Namespace Prefix:	cma_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

X

- Definition

Total automotive loans including loans to automotive dealers and to borrowers involved with automotive production.

+ References

No definition available.

+ Details

Name:	cma_TotalAutomotiveLoans
Namespace Prefix:	cma_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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

No definition available.

+ Details

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

X

- Details

Name:	us-gaap_AccountsNotesLoansAndFinancingReceivablesByIndustryOfCounterpartyTypeAxis=cma_AutomotiveProductionMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_AccountsNotesLoansAndFinancingReceivablesByIndustryOfCounterpartyTypeAxis=cma_AutomotiveDealerMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: