XML 103 R94.htm IDEA: XBRL DOCUMENT
v3.22.2.2

Fair Value Measurements and Disclosures (Schedule of Quantitative Information about Level Three Fair Value Measurements - Nonrecurring Basis) (Details) | 9 Months Ended
--- | ---
Sep. 30, 2022 USD ($)
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
Valuation Technique, Discounted cash flow | Discounted cash flow |
Mortgage Servicing Rights |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
Loans in foreclosure | $ 1,000 |
Mortgage Servicing Rights | Minimum [Member] |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
Discount rate | 9.51% |
Prepayment speeds (CPR)* | 6.25% | [1]
Performing loans | $ 70 |
Delinquent loans | $ 200 |
Mortgage Servicing Rights | Maximum [Member] |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
Discount rate | 9.81% |
Prepayment speeds (CPR)* | 6.53% | [1]
Performing loans | $ 72 |
Delinquent loans | $ 750 |
Mortgage Servicing Rights | Weighted Average [Member] |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
Discount rate | 9.61% | [1]
Prepayment speeds (CPR)* | 6.32% | [1]
Performing loans | $ 71 | [1]
[1] | *Ranges and weighted averages based on interest rate tranches

X
- Definition Fair value, discounted cash flow, valuation techniques. + References No definition available. + Details
Name: | cbsh_FairValueDiscountedCashFlowValuationTechniques
Namespace Prefix: | cbsh_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Unobservable Input, Discount Rate + References No definition available. + Details
Name: | cbsh_UnobservableInputDiscountRate
Namespace Prefix: | cbsh_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Unobservable Input, Loan Servicing Costs, Delinquent Loans + References No definition available. + Details
Name: | cbsh_UnobservableInputLoanServicingCostsDelinquentLoans
Namespace Prefix: | cbsh_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Unobservable Input, Loan Servicing Costs, Performing Loans + References No definition available. + Details
Name: | cbsh_UnobservableInputLoanServicingCostsPerformingLoans
Namespace Prefix: | cbsh_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Unobservable Input, Prepayment Speed + References No definition available. + Details
Name: | cbsh_UnobservableInputPrepaymentSpeed
Namespace Prefix: | cbsh_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Unobservable Inputs, Loan Servicing Costs, Loans in Foreclosure + References No definition available. + Details
Name: | cbsh_UnobservableInputsLoanServicingCostsLoansInForeclosure
Namespace Prefix: | cbsh_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

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_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_FairValueByAssetClassAxis=cbsh_MortgageServicingRightsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_MinimumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_MaximumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_WeightedAverageMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |