XML 103 R86.htm IDEA: XBRL DOCUMENT
v3.24.0.1

Derivative And Credit-Related Financial Instruments (Summary Of Criticized Letters Of Credit) (Details) - USD ($) $ in Millions | Dec. 31, 2023 | Dec. 31, 2022
--- | --- | ---
Derivative Instruments and Hedging Activities Disclosure [Abstract] |  |
Total criticized standby and commercial letters of credit | $ 50 | $ 37
As a percentage of total outstanding standby and commercial letters of credit | 1.40% | 1.00%

X
- Definition Total internally classified watch list standby and commercial letters of credit (generally consistent with regulatory defined special mention, substandard and doubtful). + References No definition available. + Details
Name: | cma_TotalInternallyClassifiedWatchListLettersOfCredit
Namespace Prefix: | cma_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Total internally classified watch list standby and commercial letters of credit as a percentage of total standby and commercial letters of credit. + References No definition available. + Details
Name: | cma_WatchListLettersOfCreditAsPercentageOfTotalLettersOfCredit
Namespace Prefix: | cma_
Data Type: | dtr-types1:percentItemType
Balance Type: | na
Period Type: | instant

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