XML 91 R73.htm IDEA: XBRL DOCUMENT
v3.22.0.1

Credit Quality And Allowance For Credit Losses (Narrative) (Details) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2021 | Dec. 31, 2020
Loan interest receivable | $ 120 | $ 141
Financing Receivable, Nonaccrual, Interest Income | 0 | 0
Foreclosed property | 1 | 8
Retail loans secured by residential real estate in process of foreclosure | 0 | 0
Commitments to lend additional funds to TDR borrowers | 0 | 0
Loans with terms extended in accordance with CARES Act | $ 22 | $ 72
Principal deferrals |  |
Minimum period loan terms were extended | 90 days | 90 days
Subsequent default during period | $ 0 | $ 10
Interest Rate Reductions |  |
Minimum period loan terms were extended | 90 days | 90 days
Subsequent default during period | $ 0 | $ 0

X
- Definition Days that a principal or interest payment is past due to be defined as a subsequent default + References No definition available. + Details
Name: | cma_Dayspastduedefinedassubsequentdefault
Namespace Prefix: | cma_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Loan interest receivable + References No definition available. + Details
Name: | cma_LoanInterestReceivable
Namespace Prefix: | cma_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Loans with terms extended in accordance with CARES Act + References No definition available. + Details
Name: | cma_LoansWithTermsExtendedInAccordanceWithCARESAct
Namespace Prefix: | cma_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of financing receivable modified as troubled debt restructuring within previous 12 months, with subsequent payment default. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 34 -Subparagraph (a)(2) -URI http://asc.fasb.org/extlink&oid=123577603&loc=SL6953682-111524 + Details
Name: | us-gaap_FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of interest income on financing receivable on nonaccrual status. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 20 -Section 50 -Paragraph 16 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=124255953&loc=SL82919258-210447 + Details
Name: | us-gaap_FinancingReceivableNonaccrualInterestIncome
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Carrying amount as of the balance sheet date of all assets obtained in full or partial satisfaction of a debt arrangement through foreclosure proceedings or defeasance; includes real and personal property; equity interests in corporations, partnerships, and joint ventures; and beneficial interests in trusts. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 11 -URI http://asc.fasb.org/extlink&oid=123577603&loc=d3e5162-111524 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 45 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=124259787&loc=d3e4437-111522 + Details
Name: | us-gaap_ForeclosedAssets
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of unfunded portion of contractual agreement to lend funds to borrower for financing receivable modified as troubled debt restructuring. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 40 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=121585226&loc=d3e18794-111554 + Details
Name: | us-gaap_LoansAndLeasesReceivableImpairedCommitmentToLend
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Recorded investment of consumer mortgage loan receivables secured by residential real estate properties for which formal foreclosure proceedings are in process. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 35 -URI http://asc.fasb.org/extlink&oid=123577603&loc=SL49126937-111524 + Details
Name: | us-gaap_MortgageLoansInProcessOfForeclosureAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Details
Name: | us-gaap_LoanRestructuringModificationAxis=us-gaap_PaymentDeferralMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LoanRestructuringModificationAxis=us-gaap_ContractualInterestRateReductionMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |