XML 59 R49.htm IDEA: XBRL DOCUMENT
v3.26.1

Loans And Allowance For Credit Losses (Summary Classification Of Held To Maturity Loan Portfolio) (Details) - USD ($) $ in Thousands | Mar. 31, 2026 | Dec. 31, 2025
--- | --- | ---
Loans And Allowance For Loan Losses [Line Items] |  |
Loans | $ 20,461,064 | $ 17,771,263
Commercial Portfolio Segment [Member] |  |
Loans And Allowance For Loan Losses [Line Items] |  |
Loans | 12,391,684 | 11,551,959
Personal Banking Portfolio Segment [Member] |  |
Loans And Allowance For Loan Losses [Line Items] |  |
Loans | 8,069,380 | 6,219,304
Business Loan [Member] |  |
Loans And Allowance For Loan Losses [Line Items] |  |
Loans | 6,750,356 | 6,439,380
Business Loan [Member] | Commercial Portfolio Segment [Member] |  |
Loans And Allowance For Loan Losses [Line Items] |  |
Loans | 6,750,356 | 6,439,380
Real estate - construction and land |  |
Loans And Allowance For Loan Losses [Line Items] |  |
Loans | 1,581,789 | 1,438,012
Real estate - construction and land | Commercial Portfolio Segment [Member] |  |
Loans And Allowance For Loan Losses [Line Items] |  |
Loans | 1,581,789 | 1,438,012
Business Real Estate Loan [Member] |  |
Loans And Allowance For Loan Losses [Line Items] |  |
Loans | 4,059,539 | 3,674,567
Business Real Estate Loan [Member] | Commercial Portfolio Segment [Member] |  |
Loans And Allowance For Loan Losses [Line Items] |  |
Loans | 4,059,539 | 3,674,567
Personal Real Estate Loan [Member] |  |
Loans And Allowance For Loan Losses [Line Items] |  |
Loans | 4,407,606 | 3,053,435
Personal Real Estate Loan [Member] | Personal Banking Portfolio Segment [Member] |  |
Loans And Allowance For Loan Losses [Line Items] |  |
Loans | 4,407,606 | 3,053,435
Consumer Loan [Member] |  |
Loans And Allowance For Loan Losses [Line Items] |  |
Loans | 2,475,353 | 2,196,822
Consumer Loan [Member] | Personal Banking Portfolio Segment [Member] |  |
Loans And Allowance For Loan Losses [Line Items] |  |
Loans | 2,475,353 | 2,196,822
Revolving home equity |  |
Loans And Allowance For Loan Losses [Line Items] |  |
Loans | 619,178 | 375,159
Revolving home equity | Personal Banking Portfolio Segment [Member] |  |
Loans And Allowance For Loan Losses [Line Items] |  |
Loans | 619,178 | 375,159
Credit Card Receivable [Member] |  |
Loans And Allowance For Loan Losses [Line Items] |  |
Loans | 557,733 | 589,694
Credit Card Receivable [Member] | Personal Banking Portfolio Segment [Member] |  |
Loans And Allowance For Loan Losses [Line Items] |  |
Loans | 557,733 | 589,694
Overdrafts |  |
Loans And Allowance For Loan Losses [Line Items] |  |
Loans | 9,510 | 4,194
Overdrafts | Personal Banking Portfolio Segment [Member] |  |
Loans And Allowance For Loan Losses [Line Items] |  |
Loans | $ 9,510 | $ 4,194

X
- Definition Amortized cost excluding accrued interest, before allowance for credit loss, of financing receivable. Excludes net investment in lease. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 45 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479344/326-20-45-1 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 3B -Publisher FASB -URI https://asc.fasb.org/1943274/2147479319/326-20-50-3B Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479319/326-20-50-5 + Details
Name: | us-gaap_FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

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

X
- Details
Name: | us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_CommercialPortfolioSegmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivablePortfolioSegmentAxis=cbsh_PersonalBankingPortfolioSegmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=cbsh_BusinessLoanMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=cbsh_ConstructionAndLandLoansMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=cbsh_BusinessRealEstateLoanMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=cbsh_PersonalRealEstateLoanMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_ConsumerLoanMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_RevolvingCreditFacilityMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_CreditCardReceivablesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=cbsh_OverdraftsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |