XML 66 R56.htm IDEA: XBRL DOCUMENT
v3.25.1

Derivative And Credit-Related Financial Instruments (Schedule Of Weighted Average Maturity And Interest Rates On Risk Management Cash Flow Swaps) (Details) - USD ($) $ in Millions | Mar. 31, 2025 | Dec. 31, 2024
--- | --- | ---
Schedule of Weighted Average Maturity And Interest Rates On Risk Management Cash Flow Swaps [Line Items] |  |  |
Notional/contract amount | [1] | $ 70,187 | $ 69,729
Risk management purposes |  |  |
Schedule of Weighted Average Maturity And Interest Rates On Risk Management Cash Flow Swaps [Line Items] |  |  |
Notional/contract amount | [1] | $ 29,694 | $ 30,603
Variable rate loans | Swaps - cash flow - receive fixed/pay floating rate | Risk management purposes | Cash flow swap |  |  |
Schedule of Weighted Average Maturity And Interest Rates On Risk Management Cash Flow Swaps [Line Items] |  |  |
Receive rate |  | 2.55% | 2.55%
Pay rate | [2] | 4.35% | 4.55%
[1] | Notional or contractual amounts, which represent the extent of involvement in the derivatives market, are used to determine the contractual cash flows required in accordance with the terms of the agreement. These amounts are typically not exchanged, significantly exceed amounts subject to credit or market risk and are not reflected in the Consolidated Balance Sheets.
[2] | Variable rates paid on receive fixed swaps designated as cash flow hedges were based on Secured Overnight Financing Rate (SOFR) rates in effect at March 31, 2025 and December 31, 2024.

X
- Definition Schedule of Weighted Average Maturity And Interest Rates On Risk Management Cash Flow Swaps + References No definition available. + Details
Name: | cma_ScheduleOfWeightedAverageMaturityAndInterestRatesOnRiskManagementCashFlowSwapsLineItems
Namespace Prefix: | cma_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Average fixed interest rate related to the group of interest rate derivatives. + References No definition available. + Details
Name: | us-gaap_DerivativeAverageFixedInterestRate
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Average variable interest rate related to the group of interest rate derivatives. + References No definition available. + Details
Name: | us-gaap_DerivativeAverageVariableInterestRate
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Nominal or face amount used to calculate payment on derivative. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 815 -SubTopic 10 -Name Accounting Standards Codification -Section 55 -Paragraph 181 -Publisher FASB -URI https://asc.fasb.org/1943274/2147480401/815-10-55-181 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 815 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 1B -Publisher FASB -URI https://asc.fasb.org/1943274/2147480434/815-10-50-1B Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 815 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 1A -Subparagraph (d) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480434/815-10-50-1A + Details
Name: | us-gaap_DerivativeNotionalAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | na
Period Type: | instant

X
- Details
Name: | cma_DerivativePurposeAxis=cma_RiskManagementDerivativesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_BalanceSheetLocationAxis=us-gaap_LoansMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis=us-gaap_CashFlowHedgingMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=us-gaap_SwapMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |