XML 128 R111.htm IDEA: XBRL DOCUMENT
v3.24.0.1

Employee Benefit Plans (Fair Values of the Corporation's Qualified Defined Benefit Pension Plan Investments Measured at Fair Value on a Recurring Basis) (Details) - USD ($) $ in Millions | Dec. 31, 2023 | Dec. 31, 2022
--- | --- | ---
Fair value of plan assets in qualified defined benefit pension plan, Excluding assets valued at net asset value | $ 1,397 | $ 1,269
Fair value of plan assets in qualified defined benefit pension plan | 2,665 | 2,499
Debt securities | U.S. Treasury and other U.S. government agency securities |  |
Fair value of plan assets in qualified defined benefit pension plan | 567 | 534
Debt securities | Corporate and municipal bonds and notes |  |
Fair value of plan assets in qualified defined benefit pension plan | 786 | 676
Debt securities | Mortgage-backed secutities |  |
Fair value of plan assets in qualified defined benefit pension plan |  | 20
Debt securities | Collective investments funds |  |
Fair value of plan assets in qualified defined benefit pension plan | 1,268 | 1,230
Private placements | Private placements |  |
Fair value of plan assets in qualified defined benefit pension plan | 44 | 39
Level 1 |  |
Fair value of plan assets in qualified defined benefit pension plan, Excluding assets valued at net asset value | 564 | 531
Level 1 | Debt securities | U.S. Treasury and other U.S. government agency securities |  |
Fair value of plan assets in qualified defined benefit pension plan | 564 | 531
Level 1 | Debt securities | Corporate and municipal bonds and notes |  |
Fair value of plan assets in qualified defined benefit pension plan | 0 | 0
Level 1 | Debt securities | Mortgage-backed secutities |  |
Fair value of plan assets in qualified defined benefit pension plan |  | 0
Level 1 | Private placements |  |
Fair value of plan assets in qualified defined benefit pension plan | 0 |
Level 1 | Private placements | Private placements |  |
Fair value of plan assets in qualified defined benefit pension plan |  | 0
Level 2 |  |
Fair value of plan assets in qualified defined benefit pension plan, Excluding assets valued at net asset value | 789 | 699
Level 2 | Debt securities | U.S. Treasury and other U.S. government agency securities |  |
Fair value of plan assets in qualified defined benefit pension plan | 3 | 3
Level 2 | Debt securities | Corporate and municipal bonds and notes |  |
Fair value of plan assets in qualified defined benefit pension plan | 786 | 676
Level 2 | Debt securities | Mortgage-backed secutities |  |
Fair value of plan assets in qualified defined benefit pension plan |  | 20
Level 2 | Private placements |  |
Fair value of plan assets in qualified defined benefit pension plan | 0 |
Level 2 | Private placements | Private placements |  |
Fair value of plan assets in qualified defined benefit pension plan |  | 0
Level 3 |  |
Fair value of plan assets in qualified defined benefit pension plan, Excluding assets valued at net asset value | 44 | 39
Level 3 | Debt securities | U.S. Treasury and other U.S. government agency securities |  |
Fair value of plan assets in qualified defined benefit pension plan | 0 | 0
Level 3 | Debt securities | Corporate and municipal bonds and notes |  |
Fair value of plan assets in qualified defined benefit pension plan | 0 | 0
Level 3 | Debt securities | Mortgage-backed secutities |  |
Fair value of plan assets in qualified defined benefit pension plan |  | 0
Level 3 | Private placements | Private placements |  |
Fair value of plan assets in qualified defined benefit pension plan | $ 44 | $ 39

X
- Definition Total assets at fair value in the fair value hierarchy valued on a nonrecurring basis. + References No definition available. + Details
Name: | cma_AssetsFairValueDisclosureExcludingAssetsValuedatNAV
Namespace Prefix: | cma_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of asset segregated and restricted to provide benefit under defined benefit plan. Asset includes, but is not limited to, stock, bond, other investment, earning from investment, and contribution by employer and employee. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 17 -Publisher FASB -URI https://asc.fasb.org//1943274/2147480482/715-20-55-17 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (d)(iv)(02) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-1 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (d)(ii) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-1 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (d)(iv)(01) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-1 Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-1 Reference 6: http://www.xbrl.org/2003/role/exampleRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (d)(ii) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-1 Reference 7: http://www.xbrl.org/2003/role/exampleRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (d)(iv)(01) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-1 + Details
Name: | us-gaap_DefinedBenefitPlanFairValueOfPlanAssets
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Details
Name: | us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=us-gaap_DebtSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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

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

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

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

X
- Details
Name: | us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=us-gaap_PrivatePlacementMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel1Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel2Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel3Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |