$CBSH
COMMERCE BANCSHARES INC /MO/ Stock $cbsh

$cbsh Overview Financials Valuation SEC Filings Company Website

2019 Q4 Form 10-Q Financial Statement

#000002235619000043 Filed on November 04, 2019

Income Statement

Concept	2019 Q4	2019 Q3	2018 Q3
Revenue		$0.00	$0.00
YoY Change
Cost Of Revenue
YoY Change
Gross Profit
YoY Change
Gross Profit Margin
Selling, General & Admin
YoY Change
% of Gross Profit
Research & Development
YoY Change
% of Gross Profit
Depreciation & Amortization	$10.40M	$10.40M	$9.600M
YoY Change	5.05%	8.33%	0.0%
% of Gross Profit
Operating Expenses
YoY Change
Operating Profit
YoY Change
Interest Expense		$28.23M	$17.00M
YoY Change		66.09%	45.86%
% of Operating Profit
Other Income/Expense, Net
YoY Change
Pretax Income	$135.5M	$139.2M	$140.7M
YoY Change	-1.31%	-1.09%	32.1%
Income Tax	$28.20M	$29.10M	$26.65M
% Of Pretax Income	20.81%	20.91%	18.94%
Net Earnings	$106.9M	$109.2M	$112.6M
YoY Change	-2.55%	-2.96%	50.98%
Net Earnings / Revenue
Basic Earnings Per Share		$0.93	$0.99
Diluted Earnings Per Share	$865.6K	$0.93	$0.98
COMMON SHARES
Basic Shares Outstanding	107.3M shares	109.7M shares	106.6M shares
Diluted Shares Outstanding

Balance Sheet

Concept	2019 Q4	2019 Q3	2018 Q3
SHORT-TERM ASSETS
Cash & Short-Term Investments
YoY Change
Cash & Equivalents	$907.8M	$884.4M	$805.2M
Short-Term Investments
Other Short-Term Assets
YoY Change
Inventory
Prepaid Expenses
Receivables
Other Receivables
Total Short-Term Assets
YoY Change
LONG-TERM ASSETS
Property, Plant & Equipment	$370.6M	$365.9M	$331.9M
YoY Change	11.26%	10.27%	-1.04%
Goodwill	$138.9M	$138.9M	$138.9M
YoY Change	0.0%	0.0%	0.0%
Intangibles	$9.534M	$9.139M	$8.470M
YoY Change	8.41%	7.9%	14.65%
Long-Term Investments	$0.00
YoY Change
Other Assets
YoY Change
Total Long-Term Assets
YoY Change
TOTAL ASSETS
Total Short-Term Assets
Total Long-Term Assets
Total Assets	$26.07B	$25.88B	$25.06B
YoY Change	2.36%	3.25%	0.33%
SHORT-TERM LIABILITIES
YoY Change
Accounts Payable
YoY Change
Accrued Expenses	$27.00M	$27.00M
YoY Change
Deferred Revenue
YoY Change
Short-Term Debt	$1.851B	$1.641B	$1.862B
YoY Change	-5.37%	-11.87%	32.15%
Long-Term Debt Due
YoY Change
Total Short-Term Liabilities	$27.00M	$27.00M	$1.862B
YoY Change	-98.62%	-98.55%	32.15%
LONG-TERM LIABILITIES
Long-Term Debt	$2.000M	$257.0M	$2.000M
YoY Change	-77.78%	12750.0%	-98.06%
Other Long-Term Liabilities	$527.0M	$535.0M	$257.0M
YoY Change	121.43%	108.17%	-19.44%
Total Long-Term Liabilities	$529.0M	$792.0M	$259.0M
YoY Change	114.17%	205.79%	-38.63%
TOTAL LIABILITIES
Total Short-Term Liabilities	$27.00M	$27.00M	$1.862B
Total Long-Term Liabilities	$529.0M	$792.0M	$259.0M
Total Liabilities	$22.93B	$22.77B	$22.25B
YoY Change	1.78%	2.32%	-0.09%
SHAREHOLDERS EQUITY
Retained Earnings	$201.6M	$463.2M	$493.6M
YoY Change	-16.42%	-6.16%	12.12%
Common Stock	$564.0M	$559.4M	$535.4M
YoY Change	0.81%	4.49%	4.98%
Preferred Stock
YoY Change
Treasury Stock (at cost)	$37.55M	$251.7M	$33.17M
YoY Change	9.67%	658.62%	235.26%
Treasury Stock Shares	446.0K shares	4.315M shares	516.5K shares
Shareholders Equity	$3.135B	$3.103B	$2.803B
YoY Change
Total Liabilities & Shareholders Equity	$26.07B	$25.88B	$25.06B
YoY Change	2.36%	3.25%	0.33%

Cashflow Statement

Concept	2019 Q4	2019 Q3	2018 Q3
OPERATING ACTIVITIES
Net Income	$106.9M	$109.2M	$112.6M
YoY Change	-2.55%	-2.96%	50.98%
Depreciation, Depletion And Amortization	$10.40M	$10.40M	$9.600M
YoY Change	5.05%	8.33%	0.0%
Cash From Operating Activities	$135.5M	$125.6M	$158.6M
YoY Change	27.83%	-20.81%	24.69%
INVESTING ACTIVITIES
Capital Expenditures	-$13.20M	-$9.100M	-$7.900M
YoY Change	10.92%	15.19%	-10.23%
Acquisitions
YoY Change
Other Investing Activities	-$262.8M	-$297.1M	-$371.8M
YoY Change	-650.94%	-20.09%	-301.08%
Cash From Investing Activities	-$275.9M	-$306.3M	-$379.7M
YoY Change	-870.67%	-19.33%	-315.49%
FINANCING ACTIVITIES
Cash Dividend Paid
YoY Change
Common Stock Issuance & Retirement, Net
YoY Change
Debt Paid & Issued, Net
YoY Change
Cash From Financing Activities	163.8M	103.6M	478.6M
YoY Change	-37.58%	-78.35%	-308.27%
NET CHANGE
Cash From Operating Activities	135.5M	125.6M	158.6M
Cash From Investing Activities	-275.9M	-306.3M	-379.7M
Cash From Financing Activities	163.8M	103.6M	478.6M
Net Change In Cash	23.40M	-77.10M	257.5M
YoY Change	-94.21%	-129.94%	249.86%
FREE CASH FLOW
Cash From Operating Activities	$135.5M	$125.6M	$158.6M
Capital Expenditures	-$13.20M	-$9.100M	-$7.900M
Free Cash Flow	$148.7M	$134.7M	$166.5M
YoY Change	26.12%	-19.1%	22.43%

Facts In Submission

Frame	Concept Type	Concept / XBRL Key	Value	Unit
CY2019Q3	cbsh	Available For Sale Securities Pledged To Secure Structured Repurchase Agreements AvailableForSaleSecuritiesPledgedToSecureStructuredRepurchaseAgreements	205554000	USD
CY2018Q3	cbsh	Capitalized Interest Or Dividends CapitalizedInterestOrDividends	0	USD
CY2018Q4	cbsh	Available For Sale Securities Pledged To Secure Structured Repurchase Agreements AvailableForSaleSecuritiesPledgedToSecureStructuredRepurchaseAgreements	463325000	USD
CY2019Q3	cbsh	Capitalized Interest Or Dividends CapitalizedInterestOrDividends	0	USD
CY2019Q3	cbsh	Hfs Loansonnonaccrualstatus HFSLoansonnonaccrualstatus	0	USD
CY2018Q3	cbsh	Investment Securities Called InvestmentSecuritiesCalled	0	USD
	cbsh	Investment Securities Called InvestmentSecuritiesCalled	0	USD
CY2019Q3	cbsh	Investment Securities Sold InvestmentSecuritiesSold	0	USD
	cbsh	Investment Securities Sold InvestmentSecuritiesSold	0	USD
CY2019Q3	cbsh	Loans Held For Sale90 Days Past Dueand Still Accruing LoansHeldForSale90DaysPastDueandStillAccruing	0	USD
CY2018Q3	cbsh	Sales And Repayments Of Private Equity Securities SalesAndRepaymentsOfPrivateEquitySecurities	0	USD
CY2019Q3	cbsh	Sales And Repayments Of Private Equity Securities SalesAndRepaymentsOfPrivateEquitySecurities	0	USD
	dei	Amendment Flag AmendmentFlag	false
	dei	Current Fiscal Year End Date CurrentFiscalYearEndDate	--12-31
	dei	Document Fiscal Period Focus DocumentFiscalPeriodFocus	Q3
	dei	Document Fiscal Year Focus DocumentFiscalYearFocus	2019
	dei	Entity Central Index Key EntityCentralIndexKey	0000022356
CY2018Q3	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	0.224
	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	0.671
CY2019Q3	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	0.260
	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	0.780
CY2018Q4	us-gaap	Common Stock Par Or Stated Value Per Share CommonStockParOrStatedValuePerShare	5.00
CY2019Q3	us-gaap	Common Stock Par Or Stated Value Per Share CommonStockParOrStatedValuePerShare	5.00
CY2019Q3	us-gaap	Common Stock Shares Authorized CommonStockSharesAuthorized	140000000	shares
CY2018Q4	us-gaap	Common Stock Shares Issued CommonStockSharesIssued	111886450	shares
CY2019Q3	us-gaap	Common Stock Shares Issued CommonStockSharesIssued	111886450	shares
	us-gaap	Defined Benefit Plan Contributions By Employer DefinedBenefitPlanContributionsByEmployer	0	USD
CY2018Q4	us-gaap	Mortgages Held For Sale Fair Value Disclosure MortgagesHeldForSaleFairValueDisclosure	13529000	USD
CY2019Q3	us-gaap	Mortgages Held For Sale Fair Value Disclosure MortgagesHeldForSaleFairValueDisclosure	14393000	USD
CY2018Q3	us-gaap	Preferred Stock Dividends Per Share Cash Paid PreferredStockDividendsPerShareCashPaid	0.375
CY2019Q3	us-gaap	Preferred Stock Dividends Per Share Cash Paid PreferredStockDividendsPerShareCashPaid	0.375
	us-gaap	Preferred Stock Dividends Per Share Cash Paid PreferredStockDividendsPerShareCashPaid	1.125
CY2018Q3	us-gaap	Revenues Revenues	0	USD
CY2018Q4	us-gaap	Treasury Stock Shares TreasuryStockShares	555100	shares
	us-gaap	Revenues Revenues	0	USD
CY2019Q3	us-gaap	Revenues Revenues	0	USD
	us-gaap	Preferred Stock Dividends Per Share Cash Paid PreferredStockDividendsPerShareCashPaid	1.125
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CY2019Q3	us-gaap	Preferred Stock Par Or Stated Value Per Share PreferredStockParOrStatedValuePerShare	1.00
CY2018Q4	us-gaap	Preferred Stock Shares Authorized PreferredStockSharesAuthorized	2000000	shares
CY2019Q3	us-gaap	Preferred Stock Shares Authorized PreferredStockSharesAuthorized	2000000	shares
CY2018Q4	us-gaap	Preferred Stock Shares Issued PreferredStockSharesIssued	6000	shares
CY2019Q3	us-gaap	Preferred Stock Shares Issued PreferredStockSharesIssued	6000	shares
CY2019Q3	us-gaap	Treasury Stock Shares TreasuryStockShares	4314736	shares
	dei	Document Type DocumentType	10-Q
	dei	Document Quarterly Report DocumentQuarterlyReport	true
	dei	Document Period End Date DocumentPeriodEndDate	2019-09-30
	dei	Document Transition Report DocumentTransitionReport	false
	dei	Entity File Number EntityFileNumber	0-2989
	dei	Entity Registrant Name EntityRegistrantName	COMMERCE BANCSHARES, INC.
	dei	Entity Incorporation State Country Code EntityIncorporationStateCountryCode	MO
	dei	Entity Tax Identification Number EntityTaxIdentificationNumber	43-0889454
	dei	Entity Address Address Line1 EntityAddressAddressLine1	1000 Walnut,
	dei	Entity Address City Or Town EntityAddressCityOrTown	Kansas City,
	dei	Entity Address State Or Province EntityAddressStateOrProvince	MO
	dei	Entity Address Postal Zip Code EntityAddressPostalZipCode	64106
	dei	City Area Code CityAreaCode	816
	dei	Local Phone Number LocalPhoneNumber	234-2000
	dei	Entity Current Reporting Status EntityCurrentReportingStatus	Yes
	dei	Entity Interactive Data Current EntityInteractiveDataCurrent	Yes
	dei	Entity Filer Category EntityFilerCategory	Large Accelerated Filer
	dei	Entity Small Business EntitySmallBusiness	false
	dei	Entity Emerging Growth Company EntityEmergingGrowthCompany	false
	dei	Entity Shell Company EntityShellCompany	false
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	us-gaap	Interest Expense Time Deposits100000 Or More InterestExpenseTimeDeposits100000OrMore	10221000	USD
CY2019Q3	us-gaap	Interest Expense Federal Funds Purchased And Securities Sold Under Agreements To Repurchase InterestExpenseFederalFundsPurchasedAndSecuritiesSoldUnderAgreementsToRepurchase	8273000	USD
CY2018Q3	us-gaap	Interest Expense Federal Funds Purchased And Securities Sold Under Agreements To Repurchase InterestExpenseFederalFundsPurchasedAndSecuritiesSoldUnderAgreementsToRepurchase	5022000	USD
	us-gaap	Interest Expense Federal Funds Purchased And Securities Sold Under Agreements To Repurchase InterestExpenseFederalFundsPurchasedAndSecuritiesSoldUnderAgreementsToRepurchase	23839000	USD
	us-gaap	Interest Expense Federal Funds Purchased And Securities Sold Under Agreements To Repurchase InterestExpenseFederalFundsPurchasedAndSecuritiesSoldUnderAgreementsToRepurchase	12979000	USD
CY2019Q3	cbsh	Interest On Other Borrowings InterestOnOtherBorrowings	453000	USD
CY2018Q3	cbsh	Interest On Other Borrowings InterestOnOtherBorrowings	12000	USD
	cbsh	Interest On Other Borrowings InterestOnOtherBorrowings	463000	USD
	cbsh	Interest On Other Borrowings InterestOnOtherBorrowings	36000	USD
CY2019Q3	us-gaap	Interest Expense InterestExpense	28231000	USD
CY2018Q3	us-gaap	Interest Expense InterestExpense	16997000	USD
	us-gaap	Interest Expense InterestExpense	79386000	USD
	us-gaap	Interest Expense InterestExpense	44764000	USD
CY2019Q3	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	203512000	USD
CY2018Q3	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	207754000	USD
	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	618634000	USD
	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	611605000	USD
CY2019Q3	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	10963000	USD
CY2018Q3	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	9999000	USD
	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	35232000	USD
	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	30438000	USD
CY2019Q3	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	192549000	USD
CY2018Q3	cbsh	Bank Card Transaction Fees BankCardTransactionFees	42427000	USD
	cbsh	Bank Card Transaction Fees BankCardTransactionFees	126800000	USD
CY2018Q3	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	197755000	USD
	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	583402000	USD
	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	581167000	USD
CY2019Q3	cbsh	Bank Card Transaction Fees BankCardTransactionFees	44510000	USD
	cbsh	Bank Card Transaction Fees BankCardTransactionFees	127095000	USD
CY2019Q3	cbsh	Trustfeerevenue Trustfeerevenue	39592000	USD
CY2018Q3	cbsh	Trustfeerevenue Trustfeerevenue	37400000	USD
	cbsh	Trustfeerevenue Trustfeerevenue	115223000	USD
	cbsh	Trustfeerevenue Trustfeerevenue	110498000	USD
CY2019Q3	cbsh	Depositfeerevenue Depositfeerevenue	24032000	USD
CY2018Q3	cbsh	Depositfeerevenue Depositfeerevenue	23755000	USD
	cbsh	Depositfeerevenue Depositfeerevenue	71009000	USD
	cbsh	Depositfeerevenue Depositfeerevenue	70630000	USD
CY2019Q3	us-gaap	Noninterest Income Other NoninterestIncomeOther	1787000	USD
CY2018Q3	us-gaap	Noninterest Income Other NoninterestIncomeOther	1595000	USD
	us-gaap	Noninterest Income Other NoninterestIncomeOther	5610000	USD
	us-gaap	Noninterest Income Other NoninterestIncomeOther	5878000	USD
CY2019Q3	us-gaap	Brokerage Commissions Revenue BrokerageCommissionsRevenue	4030000	USD
CY2018Q3	us-gaap	Brokerage Commissions Revenue BrokerageCommissionsRevenue	3884000	USD
	us-gaap	Brokerage Commissions Revenue BrokerageCommissionsRevenue	11665000	USD
	us-gaap	Brokerage Commissions Revenue BrokerageCommissionsRevenue	11623000	USD
CY2019Q3	cbsh	Loan Fees And Sales LoanFeesAndSales	4755000	USD
CY2018Q3	cbsh	Loan Fees And Sales LoanFeesAndSales	3579000	USD
	cbsh	Loan Fees And Sales LoanFeesAndSales	12302000	USD
	cbsh	Loan Fees And Sales LoanFeesAndSales	9670000	USD
CY2019Q3	us-gaap	Noninterest Income Other Operating Income NoninterestIncomeOtherOperatingIncome	14037000	USD
CY2018Q3	us-gaap	Noninterest Income Other Operating Income NoninterestIncomeOtherOperatingIncome	11074000	USD
	us-gaap	Noninterest Income Other Operating Income NoninterestIncomeOtherOperatingIncome	38633000	USD
	us-gaap	Noninterest Income Other Operating Income NoninterestIncomeOtherOperatingIncome	32860000	USD
CY2019Q3	us-gaap	Noninterest Income NoninterestIncome	132743000	USD
CY2018Q3	us-gaap	Noninterest Income NoninterestIncome	123714000	USD
	us-gaap	Noninterest Income NoninterestIncome	381242000	USD
	us-gaap	Noninterest Income NoninterestIncome	368254000	USD
CY2019Q3	us-gaap	Gain Loss On Investments GainLossOnInvestments	4909000	USD
CY2018Q3	us-gaap	Gain Loss On Investments GainLossOnInvestments	4306000	USD
	us-gaap	Gain Loss On Investments GainLossOnInvestments	3874000	USD
	us-gaap	Gain Loss On Investments GainLossOnInvestments	6641000	USD
CY2019Q3	us-gaap	Labor And Related Expense LaborAndRelatedExpense	123836000	USD
CY2018Q3	us-gaap	Labor And Related Expense LaborAndRelatedExpense	116194000	USD
	us-gaap	Labor And Related Expense LaborAndRelatedExpense	366026000	USD
	us-gaap	Labor And Related Expense LaborAndRelatedExpense	347677000	USD
CY2019Q3	us-gaap	Occupancy Net OccupancyNet	12293000	USD
CY2018Q3	us-gaap	Occupancy Net OccupancyNet	11631000	USD
	us-gaap	Occupancy Net OccupancyNet	34939000	USD
	us-gaap	Occupancy Net OccupancyNet	34333000	USD
CY2019Q3	us-gaap	Equipment Expense EquipmentExpense	4941000	USD
CY2018Q3	us-gaap	Equipment Expense EquipmentExpense	4592000	USD
	us-gaap	Equipment Expense EquipmentExpense	14202000	USD
	us-gaap	Equipment Expense EquipmentExpense	13617000	USD
CY2019Q3	cbsh	Supplies Postage And Communication SuppliesPostageAndCommunication	5106000	USD
CY2018Q3	cbsh	Supplies Postage And Communication SuppliesPostageAndCommunication	5103000	USD
	cbsh	Supplies Postage And Communication SuppliesPostageAndCommunication	15543000	USD
	cbsh	Supplies Postage And Communication SuppliesPostageAndCommunication	15542000	USD
CY2019Q3	us-gaap	Information Technology And Data Processing InformationTechnologyAndDataProcessing	23457000	USD
CY2018Q3	us-gaap	Information Technology And Data Processing InformationTechnologyAndDataProcessing	22056000	USD
	us-gaap	Information Technology And Data Processing InformationTechnologyAndDataProcessing	68965000	USD
	us-gaap	Information Technology And Data Processing InformationTechnologyAndDataProcessing	63762000	USD
CY2019Q3	us-gaap	Marketing Expense MarketingExpense	6048000	USD
CY2018Q3	us-gaap	Marketing Expense MarketingExpense	4999000	USD
	us-gaap	Marketing Expense MarketingExpense	17963000	USD
	us-gaap	Marketing Expense MarketingExpense	14946000	USD
CY2019Q3	us-gaap	Federal Deposit Insurance Corporation Premium Expense FederalDepositInsuranceCorporationPremiumExpense	1621000	USD
CY2018Q3	us-gaap	Federal Deposit Insurance Corporation Premium Expense FederalDepositInsuranceCorporationPremiumExpense	3167000	USD
	us-gaap	Federal Deposit Insurance Corporation Premium Expense FederalDepositInsuranceCorporationPremiumExpense	5024000	USD
	us-gaap	Federal Deposit Insurance Corporation Premium Expense FederalDepositInsuranceCorporationPremiumExpense	9750000	USD
CY2019Q3	cbsh	Community Service CommunityService	564000	USD
CY2018Q3	cbsh	Community Service CommunityService	580000	USD
	cbsh	Community Service CommunityService	2008000	USD
	cbsh	Community Service CommunityService	1965000	USD
CY2019Q3	us-gaap	Other Noninterest Expense OtherNoninterestExpense	13154000	USD
CY2018Q3	us-gaap	Other Noninterest Expense OtherNoninterestExpense	16737000	USD
	us-gaap	Other Noninterest Expense OtherNoninterestExpense	47554000	USD
	us-gaap	Other Noninterest Expense OtherNoninterestExpense	47604000	USD
CY2019Q3	us-gaap	Noninterest Expense NoninterestExpense	191020000	USD
CY2018Q3	us-gaap	Noninterest Expense NoninterestExpense	185059000	USD
	us-gaap	Noninterest Expense NoninterestExpense	572224000	USD
	us-gaap	Noninterest Expense NoninterestExpense	549196000	USD
CY2019Q3	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	139181000	USD
CY2018Q3	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	140716000	USD
	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	396294000	USD
	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	406866000	USD
CY2019Q3	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	29101000	USD
CY2018Q3	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	26647000	USD
	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	80860000	USD
	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	79412000	USD
CY2019Q3	us-gaap	Profit Loss ProfitLoss	110080000	USD
CY2018Q3	us-gaap	Profit Loss ProfitLoss	114069000	USD
	us-gaap	Profit Loss ProfitLoss	315434000	USD
	us-gaap	Profit Loss ProfitLoss	327454000	USD
CY2019Q3	us-gaap	Net Income Loss Attributable To Noncontrolling Interest NetIncomeLossAttributableToNoncontrollingInterest	838000	USD
CY2018Q3	us-gaap	Net Income Loss Attributable To Noncontrolling Interest NetIncomeLossAttributableToNoncontrollingInterest	1493000	USD
	us-gaap	Net Income Loss Attributable To Noncontrolling Interest NetIncomeLossAttributableToNoncontrollingInterest	1083000	USD
	us-gaap	Net Income Loss Attributable To Noncontrolling Interest NetIncomeLossAttributableToNoncontrollingInterest	3564000	USD
CY2019Q3	us-gaap	Net Income Loss NetIncomeLoss	109242000	USD
CY2018Q3	us-gaap	Net Income Loss NetIncomeLoss	112576000	USD
	us-gaap	Net Income Loss NetIncomeLoss	314351000	USD
	us-gaap	Net Income Loss NetIncomeLoss	323890000	USD
CY2019Q3	us-gaap	Preferred Stock Dividends Income Statement Impact PreferredStockDividendsIncomeStatementImpact	2250000	USD
CY2018Q3	us-gaap	Preferred Stock Dividends Income Statement Impact PreferredStockDividendsIncomeStatementImpact	2250000	USD
	us-gaap	Preferred Stock Dividends Income Statement Impact PreferredStockDividendsIncomeStatementImpact	6750000	USD
	us-gaap	Preferred Stock Dividends Income Statement Impact PreferredStockDividendsIncomeStatementImpact	6750000	USD
CY2019Q3	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	106992000	USD
CY2018Q3	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	110326000	USD
	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	307601000	USD
	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	317140000	USD
CY2019Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.98
CY2018Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.99
	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	2.79
	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	2.83
CY2019Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.98
CY2018Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.98
	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	2.79
	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	2.82
CY2019Q3	us-gaap	Profit Loss ProfitLoss	110080000	USD
CY2018Q3	us-gaap	Profit Loss ProfitLoss	114069000	USD
	us-gaap	Profit Loss ProfitLoss	315434000	USD
	us-gaap	Profit Loss ProfitLoss	327454000	USD
CY2019Q3	cbsh	Net Unrealizedgainslossesonsecuritiesforwhichaportionofanotherthantemporaryimpairmenthasbeenrecordedinearnings NetUnrealizedgainslossesonsecuritiesforwhichaportionofanotherthantemporaryimpairmenthasbeenrecordedinearnings	-245000	USD
CY2018Q3	cbsh	Net Unrealizedgainslossesonsecuritiesforwhichaportionofanotherthantemporaryimpairmenthasbeenrecordedinearnings NetUnrealizedgainslossesonsecuritiesforwhichaportionofanotherthantemporaryimpairmenthasbeenrecordedinearnings	53000	USD
	cbsh	Net Unrealizedgainslossesonsecuritiesforwhichaportionofanotherthantemporaryimpairmenthasbeenrecordedinearnings NetUnrealizedgainslossesonsecuritiesforwhichaportionofanotherthantemporaryimpairmenthasbeenrecordedinearnings	-432000	USD
	cbsh	Net Unrealizedgainslossesonsecuritiesforwhichaportionofanotherthantemporaryimpairmenthasbeenrecordedinearnings NetUnrealizedgainslossesonsecuritiesforwhichaportionofanotherthantemporaryimpairmenthasbeenrecordedinearnings	-25000	USD
CY2019Q3	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	21030000	USD
CY2018Q3	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	-32232000	USD
	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	171421000	USD
	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	-125442000	USD
CY2019Q3	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Adjustment Net Of Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax	-389000	USD
CY2018Q3	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Adjustment Net Of Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax	-393000	USD
	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Adjustment Net Of Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax	-1166000	USD
	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Adjustment Net Of Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax	-1180000	USD
CY2019Q3	us-gaap	Other Comprehensive Income Loss Derivatives Qualifying As Hedges Net Of Tax OtherComprehensiveIncomeLossDerivativesQualifyingAsHedgesNetOfTax	14101000	USD
CY2018Q3	us-gaap	Other Comprehensive Income Loss Derivatives Qualifying As Hedges Net Of Tax OtherComprehensiveIncomeLossDerivativesQualifyingAsHedgesNetOfTax	-1029000	USD
	us-gaap	Other Comprehensive Income Loss Derivatives Qualifying As Hedges Net Of Tax OtherComprehensiveIncomeLossDerivativesQualifyingAsHedgesNetOfTax	36687000	USD
	us-gaap	Other Comprehensive Income Loss Derivatives Qualifying As Hedges Net Of Tax OtherComprehensiveIncomeLossDerivativesQualifyingAsHedgesNetOfTax	-1029000	USD
CY2019Q3	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	35275000	USD
CY2018Q3	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	-32815000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	208842000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	-125316000	USD
CY2019Q3	us-gaap	Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	145355000	USD
CY2018Q3	us-gaap	Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	81254000	USD
	us-gaap	Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	524276000	USD
	us-gaap	Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	202138000	USD
CY2019Q3	us-gaap	Comprehensive Income Net Of Tax Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest	838000	USD
CY2018Q3	us-gaap	Comprehensive Income Net Of Tax Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest	1493000	USD
	us-gaap	Comprehensive Income Net Of Tax Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest	1083000	USD
	us-gaap	Comprehensive Income Net Of Tax Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest	3564000	USD
CY2019Q3	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	144517000	USD
CY2018Q3	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	79761000	USD
	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	523193000	USD
	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	198574000	USD
CY2019Q2	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	3171363000	USD
CY2019Q3	us-gaap	Profit Loss ProfitLoss	110080000	USD
CY2019Q3	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	35275000	USD
CY2019Q3	us-gaap	Minority Interest Decrease From Distributions To Noncontrolling Interest Holders MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders	56000	USD
CY2019Q3	us-gaap	Treasury Stock Value Acquired Cost Method TreasuryStockValueAcquiredCostMethod	33891000	USD
CY2019Q3	cbsh	Accelerated Share Repurchases Initial Price Paid AcceleratedShareRepurchasesInitialPricePaid	150000000	USD
CY2019Q3	us-gaap	Stock Issued During Period Value Share Based Compensation StockIssuedDuringPeriodValueShareBasedCompensation	0	USD
CY2019Q3	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	3486000	USD
CY2019Q3	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	27993000	USD
CY2019Q3	us-gaap	Dividends Preferred Stock Cash DividendsPreferredStockCash	2250000	USD
CY2019Q3	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	3106014000	USD
CY2018Q2	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	2771383000	USD
CY2018Q3	us-gaap	Profit Loss ProfitLoss	114069000	USD
CY2018Q3	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	-32815000	USD
CY2018Q3	us-gaap	Minority Interest Decrease From Distributions To Noncontrolling Interest Holders MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders	172000	USD
CY2018Q3	us-gaap	Treasury Stock Value Acquired Cost Method TreasuryStockValueAcquiredCostMethod	20506000	USD
CY2018Q3	us-gaap	Stock Issued During Period Value Share Based Compensation StockIssuedDuringPeriodValueShareBasedCompensation	-1000	USD
CY2018Q3	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	3161000	USD
CY2018Q3	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	25059000	USD
CY2018Q3	us-gaap	Dividends Preferred Stock Cash DividendsPreferredStockCash	2250000	USD
CY2018Q3	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	2807810000	USD
CY2018Q4	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	2937149000	USD
	us-gaap	Profit Loss ProfitLoss	315434000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	208842000	USD
	us-gaap	Minority Interest Decrease From Distributions To Noncontrolling Interest Holders MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders	3520000	USD
	us-gaap	Treasury Stock Value Acquired Cost Method TreasuryStockValueAcquiredCostMethod	119970000	USD
	cbsh	Accelerated Share Repurchases Initial Price Paid AcceleratedShareRepurchasesInitialPricePaid	150000000	USD
	us-gaap	Stock Issued During Period Value Share Based Compensation StockIssuedDuringPeriodValueShareBasedCompensation	-3000	USD
	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	10365000	USD
	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	85533000	USD
	us-gaap	Dividends Preferred Stock Cash DividendsPreferredStockCash	6750000	USD
CY2019Q3	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	3106014000	USD
CY2017Q4	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	2718184000	USD
	us-gaap	Profit Loss ProfitLoss	327454000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	-125316000	USD
	us-gaap	Minority Interest Decrease From Distributions To Noncontrolling Interest Holders MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders	471000	USD
	us-gaap	Treasury Stock Value Acquired Cost Method TreasuryStockValueAcquiredCostMethod	39575000	USD
	us-gaap	Stock Issued During Period Value Share Based Compensation StockIssuedDuringPeriodValueShareBasedCompensation	-10000	USD
	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	9555000	USD
	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	75261000	USD
	us-gaap	Dividends Preferred Stock Cash DividendsPreferredStockCash	6750000	USD
CY2018Q3	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	2807810000	USD
	us-gaap	Profit Loss ProfitLoss	315434000	USD
	us-gaap	Profit Loss ProfitLoss	327454000	USD
	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	35232000	USD
	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	30438000	USD
	us-gaap	Depreciation Amortization And Accretion Net DepreciationAmortizationAndAccretionNet	30729000	USD
	us-gaap	Depreciation Amortization And Accretion Net DepreciationAmortizationAndAccretionNet	28824000	USD
	us-gaap	Accretion Amortization Of Discounts And Premiums Investments AccretionAmortizationOfDiscountsAndPremiumsInvestments	-20436000	USD
	us-gaap	Accretion Amortization Of Discounts And Premiums Investments AccretionAmortizationOfDiscountsAndPremiumsInvestments	-18758000	USD
	us-gaap	Gain Loss On Investments GainLossOnInvestments	3874000	USD
	us-gaap	Gain Loss On Investments GainLossOnInvestments	6641000	USD
	us-gaap	Gain Loss On Sale Of Loans And Leases GainLossOnSaleOfLoansAndLeases	7881000	USD
	us-gaap	Gain Loss On Sale Of Loans And Leases GainLossOnSaleOfLoansAndLeases	4770000	USD
	cbsh	Origination Of Loans Held For Sale OriginationOfLoansHeldForSale	187792000	USD
	cbsh	Origination Of Loans Held For Sale OriginationOfLoansHeldForSale	149397000	USD
	us-gaap	Proceeds From Sale Of Loans Held For Sale ProceedsFromSaleOfLoansHeldForSale	194344000	USD
	us-gaap	Proceeds From Sale Of Loans Held For Sale ProceedsFromSaleOfLoansHeldForSale	156637000	USD
	us-gaap	Increase Decrease In Trading Securities IncreaseDecreaseInTradingSecurities	428000	USD
	us-gaap	Increase Decrease In Trading Securities IncreaseDecreaseInTradingSecurities	4886000	USD
	us-gaap	Share Based Compensation ShareBasedCompensation	10365000	USD
	us-gaap	Share Based Compensation ShareBasedCompensation	9555000	USD
	us-gaap	Increase Decrease In Interest And Dividends Receivable IncreaseDecreaseInInterestAndDividendsReceivable	-229000	USD
	us-gaap	Increase Decrease In Interest And Dividends Receivable IncreaseDecreaseInInterestAndDividendsReceivable	5021000	USD
	us-gaap	Increase Decrease In Interest Payable Net IncreaseDecreaseInInterestPayableNet	5938000	USD
	us-gaap	Increase Decrease In Interest Payable Net IncreaseDecreaseInInterestPayableNet	689000	USD
	us-gaap	Increase Decrease In Accrued Income Taxes Payable IncreaseDecreaseInAccruedIncomeTaxesPayable	23530000	USD
	us-gaap	Increase Decrease In Accrued Income Taxes Payable IncreaseDecreaseInAccruedIncomeTaxesPayable	30107000	USD
	us-gaap	Increase Decrease In Other Operating Capital Net IncreaseDecreaseInOtherOperatingCapitalNet	58928000	USD
	us-gaap	Increase Decrease In Other Operating Capital Net IncreaseDecreaseInOtherOperatingCapitalNet	-14964000	USD
	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	377334000	USD
	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	446711000	USD
	cbsh	Proceedsfromsalesandmaturitiesofavailableforsaledebtequityandothersecurities Proceedsfromsalesandmaturitiesofavailableforsaledebtequityandothersecurities	379641000	USD
	cbsh	Proceedsfromsalesandmaturitiesofavailableforsaledebtequityandothersecurities Proceedsfromsalesandmaturitiesofavailableforsaledebtequityandothersecurities	193047000	USD
	us-gaap	Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities	1007553000	USD
	us-gaap	Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities	1222998000	USD
	us-gaap	Payments To Acquire Investments PaymentsToAcquireInvestments	1306607000	USD
	us-gaap	Payments To Acquire Investments PaymentsToAcquireInvestments	1520235000	USD
	us-gaap	Payments For Proceeds From Loans And Leases PaymentsForProceedsFromLoansAndLeases	357438000	USD
	us-gaap	Payments For Proceeds From Loans And Leases PaymentsForProceedsFromLoansAndLeases	3588000	USD
	us-gaap	Payments For Securities Purchased Under Agreements To Resell PaymentsForSecuritiesPurchasedUnderAgreementsToResell	150000000	USD
	us-gaap	Payments For Securities Purchased Under Agreements To Resell PaymentsForSecuritiesPurchasedUnderAgreementsToResell	100000000	USD
	us-gaap	Proceeds From Securities Purchased Under Agreements To Resell ProceedsFromSecuritiesPurchasedUnderAgreementsToResell	0	USD
	us-gaap	Proceeds From Securities Purchased Under Agreements To Resell ProceedsFromSecuritiesPurchasedUnderAgreementsToResell	100000000	USD
	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	29441000	USD
	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	21358000	USD
	us-gaap	Proceeds From Sale Of Property Plant And Equipment ProceedsFromSaleOfPropertyPlantAndEquipment	2029000	USD
	us-gaap	Proceeds From Sale Of Property Plant And Equipment ProceedsFromSaleOfPropertyPlantAndEquipment	2342000	USD
	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-454263000	USD
	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-126794000	USD
	cbsh	Net Increase Decrease Non Interest Bearing Savings Interest Checking And Money Market Deposits NetIncreaseDecreaseNonInterestBearingSavingsInterestCheckingAndMoneyMarketDeposits	-230229000	USD
	cbsh	Net Increase Decrease Non Interest Bearing Savings Interest Checking And Money Market Deposits NetIncreaseDecreaseNonInterestBearingSavingsInterestCheckingAndMoneyMarketDeposits	-177368000	USD
	us-gaap	Increase Decrease In Time Deposits IncreaseDecreaseInTimeDeposits	411098000	USD
	us-gaap	Increase Decrease In Time Deposits IncreaseDecreaseInTimeDeposits	-94906000	USD
	us-gaap	Increase Decrease In Federal Funds Purchased And Securities Sold Under Agreements To Repurchase Net IncreaseDecreaseInFederalFundsPurchasedAndSecuritiesSoldUnderAgreementsToRepurchaseNet	-315115000	USD
	us-gaap	Increase Decrease In Federal Funds Purchased And Securities Sold Under Agreements To Repurchase Net IncreaseDecreaseInFederalFundsPurchasedAndSecuritiesSoldUnderAgreementsToRepurchaseNet	354979000	USD
	us-gaap	Repayments Of Long Term Debt RepaymentsOfLongTermDebt	163000	USD
	us-gaap	Repayments Of Long Term Debt RepaymentsOfLongTermDebt	224000	USD
	us-gaap	Proceeds From Repayments Of Short Term Debt ProceedsFromRepaymentsOfShortTermDebt	248734000	USD
	us-gaap	Proceeds From Repayments Of Short Term Debt ProceedsFromRepaymentsOfShortTermDebt	0	USD
	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	119970000	USD
	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	39575000	USD
	cbsh	Acceleratedstockrepurchaseagreement Acceleratedstockrepurchaseagreement	150000000	USD
	cbsh	Acceleratedstockrepurchaseagreement Acceleratedstockrepurchaseagreement	0	USD
	cbsh	Paymentsforstockvalueissuedundersharebasedcompensationplans Paymentsforstockvalueissuedundersharebasedcompensationplans	3000	USD
	cbsh	Paymentsforstockvalueissuedundersharebasedcompensationplans Paymentsforstockvalueissuedundersharebasedcompensationplans	10000	USD
	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	85533000	USD
	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	75261000	USD
	us-gaap	Payments Of Dividends Preferred Stock And Preference Stock PaymentsOfDividendsPreferredStockAndPreferenceStock	6750000	USD
	us-gaap	Payments Of Dividends Preferred Stock And Preference Stock PaymentsOfDividendsPreferredStockAndPreferenceStock	6750000	USD
	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	-247931000	USD
	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	-39115000	USD
	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Excluding Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffect	-324860000	USD
	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Excluding Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffect	280802000	USD
CY2018Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	1209240000	USD
CY2017Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	524352000	USD
CY2019Q3	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	884380000	USD
CY2018Q3	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	805154000	USD
	us-gaap	Income Taxes Paid Net IncomeTaxesPaidNet	54161000	USD
	us-gaap	Income Taxes Paid Net IncomeTaxesPaidNet	46122000	USD
	us-gaap	Interest Paid Net InterestPaidNet	73448000	USD
	us-gaap	Interest Paid Net InterestPaidNet	44074000	USD
	us-gaap	Transfer To Other Real Estate TransferToOtherRealEstate	558000	USD
	us-gaap	Transfer To Other Real Estate TransferToOtherRealEstate	1312000	USD
CY2019Q3	us-gaap	Restricted Cash And Cash Equivalents RestrictedCashAndCashEquivalents	25100000	USD
CY2018Q3	us-gaap	Restricted Cash And Cash Equivalents RestrictedCashAndCashEquivalents	13000000.0	USD
CY2019Q3	us-gaap	Loans And Leases Receivable Gross Carrying Amount LoansAndLeasesReceivableGrossCarryingAmount	14462594000	USD
CY2018Q4	us-gaap	Loans And Leases Receivable Gross Carrying Amount LoansAndLeasesReceivableGrossCarryingAmount	14140298000	USD
CY2019Q3	us-gaap	Pledged Financial Instruments Not Separately Reported Loans Receivable Pledged For Federal Home Loan Bank Debt PledgedFinancialInstrumentsNotSeparatelyReportedLoansReceivablePledgedForFederalHomeLoanBankDebt	4000000000.0	USD
CY2019Q3	cbsh	Pledged Financial Instruments Not Separately Reported Loans Pledged For Federal Reserve Bank Debt PledgedFinancialInstrumentsNotSeparatelyReportedLoansPledgedForFederalReserveBankDebt	1600000000	USD
CY2019Q2	us-gaap	Loans And Leases Receivable Allowance LoansAndLeasesReceivableAllowance	161182000	USD
CY2018Q4	us-gaap	Loans And Leases Receivable Allowance LoansAndLeasesReceivableAllowance	159932000	USD
CY2019Q3	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	10963000	USD
	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	35232000	USD
CY2019Q3	us-gaap	Allowance For Loan And Lease Losses Write Offs AllowanceForLoanAndLeaseLossesWriteOffs	14480000	USD
	us-gaap	Allowance For Loan And Lease Losses Write Offs AllowanceForLoanAndLeaseLossesWriteOffs	43669000	USD
CY2019Q3	us-gaap	Allowance For Loan And Lease Loss Recovery Of Bad Debts AllowanceForLoanAndLeaseLossRecoveryOfBadDebts	3017000	USD
	us-gaap	Allowance For Loan And Lease Loss Recovery Of Bad Debts AllowanceForLoanAndLeaseLossRecoveryOfBadDebts	9187000	USD
CY2019Q3	us-gaap	Allowance For Loan And Lease Losses Writeoffs Net AllowanceForLoanAndLeaseLossesWriteoffsNet	11463000	USD
	us-gaap	Allowance For Loan And Lease Losses Writeoffs Net AllowanceForLoanAndLeaseLossesWriteoffsNet	34482000	USD
CY2019Q3	us-gaap	Loans And Leases Receivable Allowance LoansAndLeasesReceivableAllowance	160682000	USD
CY2019Q3	us-gaap	Loans And Leases Receivable Allowance LoansAndLeasesReceivableAllowance	160682000	USD
CY2018Q2	us-gaap	Loans And Leases Receivable Allowance LoansAndLeasesReceivableAllowance	159532000	USD
CY2017Q4	us-gaap	Loans And Leases Receivable Allowance LoansAndLeasesReceivableAllowance	159532000	USD
CY2018Q3	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	9999000	USD
	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	30438000	USD
CY2018Q3	us-gaap	Allowance For Loan And Lease Losses Write Offs AllowanceForLoanAndLeaseLossesWriteOffs	13000000	USD
	us-gaap	Allowance For Loan And Lease Losses Write Offs AllowanceForLoanAndLeaseLossesWriteOffs	40416000	USD
CY2018Q3	us-gaap	Allowance For Loan And Lease Loss Recovery Of Bad Debts AllowanceForLoanAndLeaseLossRecoveryOfBadDebts	3201000	USD
	us-gaap	Allowance For Loan And Lease Loss Recovery Of Bad Debts AllowanceForLoanAndLeaseLossRecoveryOfBadDebts	10178000	USD
CY2018Q3	us-gaap	Allowance For Loan And Lease Losses Writeoffs Net AllowanceForLoanAndLeaseLossesWriteoffsNet	9799000	USD
	us-gaap	Allowance For Loan And Lease Losses Writeoffs Net AllowanceForLoanAndLeaseLossesWriteoffsNet	30238000	USD
CY2018Q3	us-gaap	Loans And Leases Receivable Allowance LoansAndLeasesReceivableAllowance	159732000	USD
CY2018Q3	us-gaap	Loans And Leases Receivable Allowance LoansAndLeasesReceivableAllowance	159732000	USD
CY2019Q3	us-gaap	Impaired Financing Receivable Related Allowance ImpairedFinancingReceivableRelatedAllowance	2499000	USD
CY2019Q3	us-gaap	Impaired Financing Receivable Recorded Investment ImpairedFinancingReceivableRecordedInvestment	83682000	USD
CY2019Q3	cbsh	Loans And Leases Receivable Allowance Excluding Impaired Financing Receivable Related Allowance LoansAndLeasesReceivableAllowanceExcludingImpairedFinancingReceivableRelatedAllowance	158183000	USD
CY2019Q3	cbsh	Loans And Leases Receivable Excluding Impaired Financing Receivables Recorded Investment LoansAndLeasesReceivableExcludingImpairedFinancingReceivablesRecordedInvestment	14378912000	USD
CY2018Q4	us-gaap	Impaired Financing Receivable Related Allowance ImpairedFinancingReceivableRelatedAllowance	2696000	USD
CY2018Q4	us-gaap	Impaired Financing Receivable Recorded Investment ImpairedFinancingReceivableRecordedInvestment	78616000	USD
CY2018Q4	cbsh	Loans And Leases Receivable Allowance Excluding Impaired Financing Receivable Related Allowance LoansAndLeasesReceivableAllowanceExcludingImpairedFinancingReceivableRelatedAllowance	157236000	USD
CY2018Q4	cbsh	Loans And Leases Receivable Excluding Impaired Financing Receivables Recorded Investment LoansAndLeasesReceivableExcludingImpairedFinancingReceivablesRecordedInvestment	14061682000	USD
CY2019Q3	us-gaap	Financing Receivable Recorded Investment Nonaccrual Status FinancingReceivableRecordedInvestmentNonaccrualStatus	11733000	USD
CY2018Q4	us-gaap	Financing Receivable Recorded Investment Nonaccrual Status FinancingReceivableRecordedInvestmentNonaccrualStatus	12536000	USD
CY2019Q3	cbsh	Accruing Restructured Loans AccruingRestructuredLoans	71949000	USD
CY2018Q4	cbsh	Accruing Restructured Loans AccruingRestructuredLoans	66080000	USD
CY2019Q3	us-gaap	Impaired Financing Receivable Recorded Investment ImpairedFinancingReceivableRecordedInvestment	83682000	USD
CY2018Q4	us-gaap	Impaired Financing Receivable Recorded Investment ImpairedFinancingReceivableRecordedInvestment	78616000	USD
CY2019Q3	us-gaap	Impaired Financing Receivable With No Related Allowance Recorded Investment ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment	8996000	USD
CY2019Q3	us-gaap	Impaired Financing Receivable With No Related Allowance Unpaid Principal Balance ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance	15464000	USD
CY2019Q3	cbsh	Impaired Financing Receivablewith No Related Allowance Allowance ImpairedFinancingReceivablewithNoRelatedAllowanceAllowance	0	USD
CY2019Q3	us-gaap	Impaired Financing Receivable With Related Allowance Recorded Investment ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment	74686000	USD
CY2019Q3	us-gaap	Impaired Financing Receivable With Related Allowance Unpaid Principal Balance ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance	76519000	USD
CY2019Q3	us-gaap	Impaired Financing Receivable Related Allowance ImpairedFinancingReceivableRelatedAllowance	2499000	USD
CY2019Q3	us-gaap	Impaired Financing Receivable Recorded Investment ImpairedFinancingReceivableRecordedInvestment	83682000	USD
CY2019Q3	us-gaap	Impaired Financing Receivable Unpaid Principal Balance ImpairedFinancingReceivableUnpaidPrincipalBalance	91983000	USD
CY2019Q3	us-gaap	Impaired Financing Receivable Related Allowance ImpairedFinancingReceivableRelatedAllowance	2499000	USD
CY2018Q4	us-gaap	Impaired Financing Receivable With No Related Allowance Recorded Investment ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment	8725000	USD
CY2018Q4	us-gaap	Impaired Financing Receivable With No Related Allowance Unpaid Principal Balance ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance	14477000	USD
CY2018Q4	cbsh	Impaired Financing Receivablewith No Related Allowance Allowance ImpairedFinancingReceivablewithNoRelatedAllowanceAllowance	0	USD
CY2018Q4	us-gaap	Impaired Financing Receivable With Related Allowance Recorded Investment ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment	69891000	USD
CY2018Q4	us-gaap	Impaired Financing Receivable With Related Allowance Unpaid Principal Balance ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance	72597000	USD
CY2018Q4	us-gaap	Impaired Financing Receivable Related Allowance ImpairedFinancingReceivableRelatedAllowance	2696000	USD
CY2018Q4	us-gaap	Impaired Financing Receivable Recorded Investment ImpairedFinancingReceivableRecordedInvestment	78616000	USD
CY2018Q4	us-gaap	Impaired Financing Receivable Unpaid Principal Balance ImpairedFinancingReceivableUnpaidPrincipalBalance	87074000	USD
CY2018Q4	us-gaap	Impaired Financing Receivable Related Allowance ImpairedFinancingReceivableRelatedAllowance	2696000	USD
CY2019Q3	cbsh	Financing Receivable Average Recorded Investment Nonaccrual Status FinancingReceivableAverageRecordedInvestmentNonaccrualStatus	11558000	USD
CY2019Q3	cbsh	Financing Receivable Modifications Average Recorded Investment FinancingReceivableModificationsAverageRecordedInvestment	69161000	USD
CY2019Q3	us-gaap	Impaired Financing Receivable Average Recorded Investment ImpairedFinancingReceivableAverageRecordedInvestment	80719000	USD
	cbsh	Financing Receivable Average Recorded Investment Nonaccrual Status FinancingReceivableAverageRecordedInvestmentNonaccrualStatus	11955000	USD
	cbsh	Financing Receivable Modifications Average Recorded Investment FinancingReceivableModificationsAverageRecordedInvestment	63853000	USD
	us-gaap	Impaired Financing Receivable Average Recorded Investment ImpairedFinancingReceivableAverageRecordedInvestment	75808000	USD
CY2018Q3	cbsh	Financing Receivable Average Recorded Investment Nonaccrual Status FinancingReceivableAverageRecordedInvestmentNonaccrualStatus	9339000	USD
CY2018Q3	cbsh	Financing Receivable Modifications Average Recorded Investment FinancingReceivableModificationsAverageRecordedInvestment	99902000	USD
CY2018Q3	us-gaap	Impaired Financing Receivable Average Recorded Investment ImpairedFinancingReceivableAverageRecordedInvestment	109241000	USD
	cbsh	Financing Receivable Average Recorded Investment Nonaccrual Status FinancingReceivableAverageRecordedInvestmentNonaccrualStatus	10149000	USD
	cbsh	Financing Receivable Modifications Average Recorded Investment FinancingReceivableModificationsAverageRecordedInvestment	98969000	USD
	us-gaap	Impaired Financing Receivable Average Recorded Investment ImpairedFinancingReceivableAverageRecordedInvestment	109118000	USD
CY2019Q3	us-gaap	Impaired Financing Receivable Interest Income Accrual Method ImpairedFinancingReceivableInterestIncomeAccrualMethod	875000	USD
CY2018Q3	us-gaap	Impaired Financing Receivable Interest Income Accrual Method ImpairedFinancingReceivableInterestIncomeAccrualMethod	1312000	USD
	us-gaap	Impaired Financing Receivable Interest Income Accrual Method ImpairedFinancingReceivableInterestIncomeAccrualMethod	2618000	USD
	us-gaap	Impaired Financing Receivable Interest Income Accrual Method ImpairedFinancingReceivableInterestIncomeAccrualMethod	3937000	USD
CY2019Q3	cbsh	Financing Receivable Recorded Investment Currentor Lessthan30days Past Due FinancingReceivableRecordedInvestmentCurrentorLessthan30daysPastDue	14358064000	USD
CY2019Q3	cbsh	Financing Receivable Recorded Investment Thirty To Eighty Nine Days Past Due FinancingReceivableRecordedInvestmentThirtyToEightyNineDaysPastDue	76489000	USD
CY2019Q3	us-gaap	Financing Receivable Recorded Investment90 Days Past Due And Still Accruing FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing	16308000	USD
CY2019Q3	us-gaap	Financing Receivable Recorded Investment Nonaccrual Status FinancingReceivableRecordedInvestmentNonaccrualStatus	11733000	USD
CY2019Q3	us-gaap	Loans And Leases Receivable Gross Carrying Amount LoansAndLeasesReceivableGrossCarryingAmount	14462594000	USD
CY2018Q4	cbsh	Financing Receivable Recorded Investment Currentor Lessthan30days Past Due FinancingReceivableRecordedInvestmentCurrentorLessthan30daysPastDue	14038417000	USD
CY2018Q4	cbsh	Financing Receivable Recorded Investment Thirty To Eighty Nine Days Past Due FinancingReceivableRecordedInvestmentThirtyToEightyNineDaysPastDue	72687000	USD
CY2018Q4	us-gaap	Financing Receivable Recorded Investment90 Days Past Due And Still Accruing FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing	16658000	USD
CY2018Q4	us-gaap	Financing Receivable Recorded Investment Nonaccrual Status FinancingReceivableRecordedInvestmentNonaccrualStatus	12536000	USD
CY2018Q4	us-gaap	Loans And Leases Receivable Gross Carrying Amount LoansAndLeasesReceivableGrossCarryingAmount	14140298000	USD
CY2019Q3	cbsh	Credit Quality Personal Real Estate Loans Excluded CreditQualityPersonalRealEstateLoansExcluded	196100000	USD
CY2018Q4	cbsh	Credit Quality Personal Real Estate Loans Excluded CreditQualityPersonalRealEstateLoansExcluded	201700000	USD
CY2019Q3	cbsh	Consumer Healthcare Loans Excluded ConsumerHealthcareLoansExcluded	178400000	USD
CY2018Q4	cbsh	Consumer Healthcare Loans Excluded ConsumerHealthcareLoansExcluded	170300000	USD
CY2019Q3	cbsh	Credit Quality Personal Banking Loan Table Percentage Loans Excluded CreditQualityPersonalBankingLoanTablePercentageLoansExcluded	0.08	Rate
CY2019Q3	us-gaap	Financing Receivable Modifications Recorded Investment FinancingReceivableModificationsRecordedInvestment	81502000	USD
CY2018Q4	us-gaap	Financing Receivable Modifications Recorded Investment FinancingReceivableModificationsRecordedInvestment	75839000	USD
	cbsh	Period After Which Loans Are Deemed In Default PeriodAfterWhichLoansAreDeemedInDefault	P90D
CY2019Q3	us-gaap	Financing Receivable Modifications Recorded Investment FinancingReceivableModificationsRecordedInvestment	81502000	USD
CY2019Q3	cbsh	Financing Receivable Troubled Debt Restructurings That Subsequently Defaulted Recorded Investment FinancingReceivableTroubledDebtRestructuringsThatSubsequentlyDefaultedRecordedInvestment	994000	USD
	cbsh	Effect On Interest Income Resulting From Modification To Credit Card Loans EffectOnInterestIncomeResultingFromModificationToCreditCardLoans	1100000	USD
CY2019Q3	us-gaap	Loans And Leases Receivable Impaired Commitment To Lend LoansAndLeasesReceivableImpairedCommitmentToLend	5200000	USD
CY2019Q3	us-gaap	Loans Held For Sale Fair Value Disclosure LoansHeldForSaleFairValueDisclosure	14400000	USD
CY2019Q3	cbsh	Unpaid Principal Balanceon Personal Real Estate Loans Heldfor Sale UnpaidPrincipalBalanceonPersonalRealEstateLoansHeldforSale	14000000.0	USD
CY2019Q3	cbsh	Student Loans Heldfor Sale Lowerof Costor Fair Value StudentLoansHeldforSaleLowerofCostorFairValue	5700000	USD
CY2019Q3	cbsh	Hfs Loansonnonaccrualstatus HFSLoansonnonaccrualstatus	0	USD
CY2019Q3	us-gaap	Real Estate Acquired Through Foreclosure RealEstateAcquiredThroughForeclosure	502000	USD
CY2018Q4	us-gaap	Real Estate Acquired Through Foreclosure RealEstateAcquiredThroughForeclosure	1400000	USD
CY2019Q3	us-gaap	Other Foreclosed Assets OtherForeclosedAssets	1800000	USD
CY2018Q4	us-gaap	Other Foreclosed Assets OtherForeclosedAssets	2000000.0	USD
CY2019Q3	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	8660419000	USD
CY2018Q4	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	8538041000	USD
CY2019Q3	us-gaap	Trading Securities TradingSecurities	35918000	USD
CY2018Q4	us-gaap	Trading Securities TradingSecurities	27059000	USD
CY2019Q3	us-gaap	Equity Securities Fv Ni EquitySecuritiesFvNi	2902000	USD
CY2018Q4	us-gaap	Equity Securities Fv Ni EquitySecuritiesFvNi	2585000	USD
CY2019Q3	cbsh	Equtiy Securitieswithout Readily Determinable Fair Values EqutiySecuritieswithoutReadilyDeterminableFairValues	1284000	USD
CY2018Q4	cbsh	Equtiy Securitieswithout Readily Determinable Fair Values EqutiySecuritieswithoutReadilyDeterminableFairValues	1824000	USD
CY2019Q3	us-gaap	Federal Reserve Bank Stock FederalReserveBankStock	33770000	USD
CY2018Q4	us-gaap	Federal Reserve Bank Stock FederalReserveBankStock	33498000	USD
CY2019Q3	us-gaap	Federal Home Loan Bank Stock FederalHomeLoanBankStock	20000000	USD
CY2018Q4	us-gaap	Federal Home Loan Bank Stock FederalHomeLoanBankStock	10000000	USD
CY2019Q3	cbsh	Private Equity Investments PrivateEquityInvestments	93441000	USD
CY2018Q4	cbsh	Private Equity Investments PrivateEquityInvestments	85659000	USD
CY2019Q3	cbsh	Total Investment Securities TotalInvestmentSecurities	8847734000	USD
CY2018Q4	cbsh	Total Investment Securities TotalInvestmentSecurities	8698666000	USD
CY2019Q3	us-gaap	Available For Sale Debt Securities Amortized Cost Basis AvailableForSaleDebtSecuritiesAmortizedCostBasis	8496993000	USD
CY2019Q3	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	8660419000	USD
CY2019Q3	us-gaap	Available For Sale Debt Securities Amortized Cost Basis AvailableForSaleDebtSecuritiesAmortizedCostBasis	8496993000	USD
CY2019Q3	cbsh	Available For Sale Securities Gross Unreailzed Gainat Period End AvailableForSaleSecuritiesGrossUnreailzedGainatPeriodEnd	169967000	USD
CY2019Q3	cbsh	Available For Sale Securities Gross Unrealized Lossat Period End AvailableForSaleSecuritiesGrossUnrealizedLossatPeriodEnd	6541000	USD
CY2019Q3	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	8660419000	USD
CY2018Q4	us-gaap	Available For Sale Debt Securities Amortized Cost Basis AvailableForSaleDebtSecuritiesAmortizedCostBasis	8602599000	USD
CY2018Q4	cbsh	Available For Sale Securities Gross Unreailzed Gainat Period End AvailableForSaleSecuritiesGrossUnreailzedGainatPeriodEnd	35266000	USD
CY2018Q4	cbsh	Available For Sale Securities Gross Unrealized Lossat Period End AvailableForSaleSecuritiesGrossUnrealizedLossatPeriodEnd	99824000	USD
CY2018Q4	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	8538041000	USD
	cbsh	Percentage Decrease In Fair Value Below Amortized Cost PercentageDecreaseInFairValueBelowAmortizedCost	0.20
CY2019Q3	cbsh	Fair Value Securities On Other Than Temporary Impairment Watch List FairValueSecuritiesOnOtherThanTemporaryImpairmentWatchList	47900000	USD
CY2018Q4	cbsh	Fair Value Securities On Other Than Temporary Impairment Watch List FairValueSecuritiesOnOtherThanTemporaryImpairmentWatchList	57700000	USD
CY2018Q4	us-gaap	Other Than Temporary Impairment Credit Losses Recognized In Earnings Credit Losses On Debt Securities Held OtherThanTemporaryImpairmentCreditLossesRecognizedInEarningsCreditLossesOnDebtSecuritiesHeld	14092000	USD
CY2017Q4	us-gaap	Other Than Temporary Impairment Credit Losses Recognized In Earnings Credit Losses On Debt Securities Held OtherThanTemporaryImpairmentCreditLossesRecognizedInEarningsCreditLossesOnDebtSecuritiesHeld	14199000	USD
	us-gaap	Other Than Temporary Impairment Credit Losses Recognized In Earnings Additions No Previous Impairment OtherThanTemporaryImpairmentCreditLossesRecognizedInEarningsAdditionsNoPreviousImpairment	48000	USD
	us-gaap	Other Than Temporary Impairment Credit Losses Recognized In Earnings Additions No Previous Impairment OtherThanTemporaryImpairmentCreditLossesRecognizedInEarningsAdditionsNoPreviousImpairment	58000	USD
	us-gaap	Other Than Temporary Impairment Credit Losses Recognized In Earnings Additions Additional Credit Losses OtherThanTemporaryImpairmentCreditLossesRecognizedInEarningsAdditionsAdditionalCreditLosses	85000	USD
	us-gaap	Other Than Temporary Impairment Credit Losses Recognized In Earnings Additions Additional Credit Losses OtherThanTemporaryImpairmentCreditLossesRecognizedInEarningsAdditionsAdditionalCreditLosses	10000	USD
	us-gaap	Other Than Temporary Impairment Credit Losses Recognized In Earnings Reductions Cash Flows OtherThanTemporaryImpairmentCreditLossesRecognizedInEarningsReductionsCashFlows	831000	USD
	us-gaap	Other Than Temporary Impairment Credit Losses Recognized In Earnings Reductions Cash Flows OtherThanTemporaryImpairmentCreditLossesRecognizedInEarningsReductionsCashFlows	138000	USD
CY2019Q3	us-gaap	Other Than Temporary Impairment Credit Losses Recognized In Earnings Credit Losses On Debt Securities Held OtherThanTemporaryImpairmentCreditLossesRecognizedInEarningsCreditLossesOnDebtSecuritiesHeld	13394000	USD
CY2018Q3	us-gaap	Other Than Temporary Impairment Credit Losses Recognized In Earnings Credit Losses On Debt Securities Held OtherThanTemporaryImpairmentCreditLossesRecognizedInEarningsCreditLossesOnDebtSecuritiesHeld	14129000	USD
CY2019Q3	us-gaap	Available For Sale Securities Continuous Unrealized Loss Position Less Than Twelve Months Fair Value AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue	857830000	USD
CY2019Q3	us-gaap	Available For Sale Securities Continuous Unrealized Loss Position Less Than12 Months Accumulated Loss AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss	3488000	USD
CY2019Q3	us-gaap	Available For Sale Securities Continuous Unrealized Loss Position Twelve Months Or Longer Fair Value AvailableForSaleSecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue	733953000	USD
CY2019Q3	us-gaap	Available For Sale Securities Continuous Unrealized Loss Position12 Months Or Longer Accumulated Loss AvailableForSaleSecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss	3053000	USD
CY2019Q3	us-gaap	Available For Sale Securities Continuous Unrealized Loss Position Fair Value AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValue	1591783000	USD
CY2019Q3	us-gaap	Available For Sale Securities Continuous Unrealized Loss Position Accumulated Loss AvailableForSaleSecuritiesContinuousUnrealizedLossPositionAccumulatedLoss	6541000	USD
CY2018Q4	us-gaap	Available For Sale Securities Continuous Unrealized Loss Position Less Than Twelve Months Fair Value AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue	1213809000	USD
CY2018Q4	us-gaap	Available For Sale Securities Continuous Unrealized Loss Position Less Than12 Months Accumulated Loss AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss	11098000	USD
CY2018Q4	us-gaap	Available For Sale Securities Continuous Unrealized Loss Position Twelve Months Or Longer Fair Value AvailableForSaleSecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue	4221687000	USD
CY2018Q4	us-gaap	Available For Sale Securities Continuous Unrealized Loss Position12 Months Or Longer Accumulated Loss AvailableForSaleSecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss	88726000	USD
CY2018Q4	us-gaap	Available For Sale Securities Continuous Unrealized Loss Position Fair Value AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValue	5435496000	USD
CY2018Q4	us-gaap	Available For Sale Securities Continuous Unrealized Loss Position Accumulated Loss AvailableForSaleSecuritiesContinuousUnrealizedLossPositionAccumulatedLoss	99824000	USD
CY2019Q3	us-gaap	Available For Sale Securities Continuous Unrealized Loss Position Fair Value AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValue	1600000000	USD
CY2018Q4	us-gaap	Available For Sale Securities Continuous Unrealized Loss Position Fair Value AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValue	5400000000	USD
CY2019Q3	us-gaap	Available For Sale Securities Continuous Unrealized Loss Position Accumulated Loss AvailableForSaleSecuritiesContinuousUnrealizedLossPositionAccumulatedLoss	6500000	USD
	cbsh	Af Ssecuritiesinlosspositionatperiodendchangeinunrealizedloss AFSsecuritiesinlosspositionatperiodendchangeinunrealizedloss	93300000	USD
	us-gaap	Proceeds From Sale Of Available For Sale Securities ProceedsFromSaleOfAvailableForSaleSecurities	368939000	USD
	us-gaap	Proceeds From Sale Of Available For Sale Securities ProceedsFromSaleOfAvailableForSaleSecurities	153066000	USD
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	cbsh	Proceedsfromsaleofequitysecurities Proceedsfromsaleofequitysecurities	39981000	USD
	cbsh	Proceeds From Sale Of Other Securities ProceedsFromSaleOfOtherSecurities	7243000	USD
	cbsh	Proceeds From Sale Of Other Securities ProceedsFromSaleOfOtherSecurities	0	USD
	cbsh	Proceedsfromsalesandmaturitiesofavailableforsaledebtequityandothersecurities Proceedsfromsalesandmaturitiesofavailableforsaledebtequityandothersecurities	379641000	USD
	cbsh	Proceedsfromsalesandmaturitiesofavailableforsaledebtequityandothersecurities Proceedsfromsalesandmaturitiesofavailableforsaledebtequityandothersecurities	193047000	USD
	us-gaap	Gain Loss On Investments GainLossOnInvestments	3874000	USD
	us-gaap	Gain Loss On Investments GainLossOnInvestments	6641000	USD
CY2019Q3	cbsh	Investment Securities Pledged At Fair Value InvestmentSecuritiesPledgedAtFairValue	3900000000	USD
CY2019Q3	us-gaap	Financial Instruments Owned And Pledged As Collateral Amount Eligible To Be Repledged By Counterparty FinancialInstrumentsOwnedAndPledgedAsCollateralAmountEligibleToBeRepledgedByCounterparty	205600000	USD
CY2019Q3	cbsh	Investments Exceeding Ten Percent Of Stockholders Equity InvestmentsExceedingTenPercentOfStockholdersEquity	0
CY2019Q3	cbsh	Percentage Of Stockholders Equity Of Which No Investment From Single Issuer Exceeds PercentageOfStockholdersEquityOfWhichNoInvestmentFromSingleIssuerExceeds	0.10
CY2019Q3	us-gaap	Finite Lived Intangible Assets Gross FiniteLivedIntangibleAssetsGross	43468000	USD
CY2019Q3	us-gaap	Finite Lived Intangible Assets Accumulated Amortization FiniteLivedIntangibleAssetsAccumulatedAmortization	33925000	USD
CY2019Q3	us-gaap	Valuation Allowances And Reserves Balance ValuationAllowancesAndReservesBalance	404000	USD
CY2019Q3	us-gaap	Intangible Assets Net Excluding Goodwill IntangibleAssetsNetExcludingGoodwill	9139000	USD
CY2018Q4	us-gaap	Finite Lived Intangible Assets Gross FiniteLivedIntangibleAssetsGross	41609000	USD
CY2018Q4	us-gaap	Finite Lived Intangible Assets Accumulated Amortization FiniteLivedIntangibleAssetsAccumulatedAmortization	32815000	USD
CY2018Q4	us-gaap	Valuation Allowances And Reserves Balance ValuationAllowancesAndReservesBalance	0	USD
CY2018Q4	us-gaap	Intangible Assets Net Excluding Goodwill IntangibleAssetsNetExcludingGoodwill	8794000	USD
CY2019Q3	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	395000	USD
CY2018Q3	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	318000	USD
	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	1100000	USD
	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	952000	USD
CY2019Q3	us-gaap	Finite Lived Intangible Assets Amortization Expense Next Twelve Months FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths	1494000	USD
CY2019Q3	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Two FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo	1441000	USD
CY2019Q3	us-gaap	Unrecorded Unconditional Purchase Obligation Balance Sheet Amount UnrecordedUnconditionalPurchaseObligationBalanceSheetAmount	2900000	USD
CY2019Q3	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Three FiniteLivedIntangibleAssetsAmortizationExpenseYearThree	1210000	USD
CY2019Q3	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Four FiniteLivedIntangibleAssetsAmortizationExpenseYearFour	1025000	USD
CY2019Q3	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Five FiniteLivedIntangibleAssetsAmortizationExpenseYearFive	851000	USD
CY2019Q3	us-gaap	Goodwill Goodwill	138921000	USD
CY2019Q3	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	26400000	USD
CY2019Q3	us-gaap	Operating Lease Liability OperatingLeaseLiability	27100000	USD
CY2019Q3	us-gaap	Lease Cost LeaseCost	1800000	USD
	us-gaap	Lease Cost LeaseCost	5500000	USD
CY2019Q3	us-gaap	Lessee Operating Lease Liability Payments Remainder Of Fiscal Year LesseeOperatingLeaseLiabilityPaymentsRemainderOfFiscalYear	1452000	USD
CY2019Q3	us-gaap	Lessee Operating Lease Liability Payments Due Year Two LesseeOperatingLeaseLiabilityPaymentsDueYearTwo	5400000	USD
CY2019Q3	us-gaap	Lessee Operating Lease Liability Payments Due Year Three LesseeOperatingLeaseLiabilityPaymentsDueYearThree	4579000	USD
CY2019Q3	us-gaap	Lessee Operating Lease Liability Payments Due Year Four LesseeOperatingLeaseLiabilityPaymentsDueYearFour	4093000	USD
CY2019Q3	us-gaap	Lessee Operating Lease Liability Payments Due Year Five LesseeOperatingLeaseLiabilityPaymentsDueYearFive	3772000	USD
CY2019Q3	us-gaap	Lessee Operating Lease Liability Payments Due After Year Five LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive	15123000	USD
CY2019Q3	us-gaap	Lessee Operating Lease Liability Payments Due LesseeOperatingLeaseLiabilityPaymentsDue	34419000	USD
CY2019Q3	us-gaap	Lessee Operating Lease Liability Undiscounted Excess Amount LesseeOperatingLeaseLiabilityUndiscountedExcessAmount	7337000	USD
CY2019Q3	us-gaap	Operating Lease Liability OperatingLeaseLiability	27082000	USD
CY2019Q3	us-gaap	Operating Lease Weighted Average Remaining Lease Term1 OperatingLeaseWeightedAverageRemainingLeaseTerm1	P11Y9M18D
CY2019Q3	us-gaap	Operating Lease Weighted Average Discount Rate Percent OperatingLeaseWeightedAverageDiscountRatePercent	0.0372
CY2019Q3	us-gaap	Operating Lease Payments OperatingLeasePayments	1446000	USD
	us-gaap	Operating Lease Payments OperatingLeasePayments	4487000	USD
CY2019Q3	us-gaap	Right Of Use Asset Obtained In Exchange For Operating Lease Liability RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability	659000	USD
	us-gaap	Right Of Use Asset Obtained In Exchange For Operating Lease Liability RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability	2751000	USD
CY2018Q4	us-gaap	Operating Leases Future Minimum Payments Due Current OperatingLeasesFutureMinimumPaymentsDueCurrent	5763000	USD
CY2018Q4	us-gaap	Operating Leases Future Minimum Payments Due In Two Years OperatingLeasesFutureMinimumPaymentsDueInTwoYears	4817000	USD
CY2018Q4	us-gaap	Operating Leases Future Minimum Payments Due In Three Years OperatingLeasesFutureMinimumPaymentsDueInThreeYears	4055000	USD
CY2018Q4	us-gaap	Operating Leases Future Minimum Payments Due In Four Years OperatingLeasesFutureMinimumPaymentsDueInFourYears	3598000	USD
CY2018Q4	us-gaap	Operating Leases Future Minimum Payments Due In Five Years OperatingLeasesFutureMinimumPaymentsDueInFiveYears	3273000	USD
CY2018Q4	us-gaap	Operating Leases Future Minimum Payments Due Thereafter OperatingLeasesFutureMinimumPaymentsDueThereafter	15161000	USD
CY2018Q4	us-gaap	Operating Leases Future Minimum Payments Due OperatingLeasesFutureMinimumPaymentsDue	36667000	USD
CY2019Q3	us-gaap	Sales Type And Direct Financing Leases Profit Loss SalesTypeAndDirectFinancingLeasesProfitLoss	6092000	USD
	us-gaap	Sales Type And Direct Financing Leases Profit Loss SalesTypeAndDirectFinancingLeasesProfitLoss	17988000	USD
CY2019Q3	us-gaap	Operating Lease Lease Income OperatingLeaseLeaseIncome	1984000	USD
	us-gaap	Operating Lease Lease Income OperatingLeaseLeaseIncome	5816000	USD
CY2019Q3	us-gaap	Lease Income LeaseIncome	8076000	USD
	us-gaap	Lease Income LeaseIncome	23804000	USD
CY2019Q3	us-gaap	Sales Type And Direct Financing Leases Lease Receivable SalesTypeAndDirectFinancingLeasesLeaseReceivable	710676000	USD
CY2019Q3	cbsh	Salestypeand Direct Financing Leases Unguaranteed Residual Asset SalestypeandDirectFinancingLeasesUnguaranteedResidualAsset	54938000	USD
CY2019Q3	us-gaap	Net Investment In Lease NetInvestmentInLease	765614000	USD
CY2019Q3	us-gaap	Deferred Costs Leasing Net DeferredCostsLeasingNet	3546000	USD
CY2019Q3	us-gaap	Net Investment In Direct Financing And Sales Type Leases NetInvestmentInDirectFinancingAndSalesTypeLeases	769160000	USD
CY2019Q3	us-gaap	Sales Type And Direct Financing Leases Lease Receivable Payments To Be Received Remainder Of Fiscal Year SalesTypeAndDirectFinancingLeasesLeaseReceivablePaymentsToBeReceivedRemainderOfFiscalYear	51888000	USD
CY2019Q3	us-gaap	Lessor Operating Lease Payments To Be Received Remainder Of Fiscal Year LessorOperatingLeasePaymentsToBeReceivedRemainderOfFiscalYear	1918000	USD
CY2019Q3	cbsh	Lessor Total Paymentstobe Received Remainderof Fiscal Year LessorTotalPaymentstobeReceivedRemainderofFiscalYear	53806000	USD
CY2019Q3	us-gaap	Sales Type And Direct Financing Leases Lease Receivable Payments To Be Received Two Years SalesTypeAndDirectFinancingLeasesLeaseReceivablePaymentsToBeReceivedTwoYears	200390000	USD
CY2019Q3	us-gaap	Lessor Operating Lease Payments To Be Received Two Years LessorOperatingLeasePaymentsToBeReceivedTwoYears	7057000	USD
CY2019Q3	cbsh	Lessor Total Paymentstobe Received Two Years LessorTotalPaymentstobeReceivedTwoYears	207447000	USD
CY2019Q3	us-gaap	Sales Type And Direct Financing Leases Lease Receivable Payments To Be Received Three Years SalesTypeAndDirectFinancingLeasesLeaseReceivablePaymentsToBeReceivedThreeYears	156798000	USD
CY2019Q3	us-gaap	Lessor Operating Lease Payments To Be Received Three Years LessorOperatingLeasePaymentsToBeReceivedThreeYears	7036000	USD
CY2019Q3	cbsh	Lessor Total Paymentstobe Received Three Years LessorTotalPaymentstobeReceivedThreeYears	163834000	USD
CY2019Q3	us-gaap	Sales Type And Direct Financing Leases Lease Receivable Payments To Be Received Four Years SalesTypeAndDirectFinancingLeasesLeaseReceivablePaymentsToBeReceivedFourYears	117779000	USD
CY2019Q3	us-gaap	Lessor Operating Lease Payments To Be Received Four Years LessorOperatingLeasePaymentsToBeReceivedFourYears	13314000	USD
CY2019Q3	cbsh	Lessor Total Paymentstobe Received Four Years LessorTotalPaymentstobeReceivedFourYears	131093000	USD
CY2019Q3	us-gaap	Sales Type And Direct Financing Leases Lease Receivable Payments To Be Received Five Years SalesTypeAndDirectFinancingLeasesLeaseReceivablePaymentsToBeReceivedFiveYears	86746000	USD
CY2019Q3	us-gaap	Lessor Operating Lease Payments To Be Received Five Years LessorOperatingLeasePaymentsToBeReceivedFiveYears	5084000	USD
CY2019Q3	cbsh	Lessor Total Paymentstobe Received Five Years LessorTotalPaymentstobeReceivedFiveYears	91830000	USD
CY2019Q3	us-gaap	Sales Type And Direct Financing Leases Lease Receivable Payments To Be Received Thereafter SalesTypeAndDirectFinancingLeasesLeaseReceivablePaymentsToBeReceivedThereafter	160852000	USD
CY2019Q3	us-gaap	Lessor Operating Lease Payments To Be Received Thereafter LessorOperatingLeasePaymentsToBeReceivedThereafter	13096000	USD
CY2019Q3	cbsh	Lessor Total Paymentstobe Received Thereafter LessorTotalPaymentstobeReceivedThereafter	173948000	USD
CY2019Q3	us-gaap	Sales Type And Direct Financing Leases Lease Receivable Payments To Be Received SalesTypeAndDirectFinancingLeasesLeaseReceivablePaymentsToBeReceived	774453000	USD
CY2019Q3	us-gaap	Lessor Operating Lease Payments To Be Received LessorOperatingLeasePaymentsToBeReceived	47505000	USD
CY2019Q3	cbsh	Lessor Total Paymentstobe Received LessorTotalPaymentstobeReceived	821958000	USD
CY2019Q3	us-gaap	Sales Type And Direct Financing Leases Lease Receivable Undiscounted Excess Amount SalesTypeAndDirectFinancingLeasesLeaseReceivableUndiscountedExcessAmount	63777000	USD
CY2019Q3	us-gaap	Sales Type And Direct Financing Leases Lease Receivable SalesTypeAndDirectFinancingLeasesLeaseReceivable	710676000	USD
CY2019Q3	us-gaap	Defined Benefit Plan Service Cost DefinedBenefitPlanServiceCost	159000	USD
CY2018Q3	us-gaap	Defined Benefit Plan Service Cost DefinedBenefitPlanServiceCost	127000	USD
	us-gaap	Defined Benefit Plan Service Cost DefinedBenefitPlanServiceCost	477000	USD
	us-gaap	Defined Benefit Plan Service Cost DefinedBenefitPlanServiceCost	432000	USD
CY2019Q3	us-gaap	Defined Benefit Plan Interest Cost DefinedBenefitPlanInterestCost	1065000	USD
CY2018Q3	us-gaap	Defined Benefit Plan Interest Cost DefinedBenefitPlanInterestCost	916000	USD
	us-gaap	Defined Benefit Plan Interest Cost DefinedBenefitPlanInterestCost	3195000	USD
	us-gaap	Defined Benefit Plan Interest Cost DefinedBenefitPlanInterestCost	2817000	USD
CY2019Q3	us-gaap	Defined Benefit Plan Expected Return On Plan Assets DefinedBenefitPlanExpectedReturnOnPlanAssets	1196000	USD
CY2018Q3	us-gaap	Defined Benefit Plan Expected Return On Plan Assets DefinedBenefitPlanExpectedReturnOnPlanAssets	1067000	USD
	us-gaap	Defined Benefit Plan Expected Return On Plan Assets DefinedBenefitPlanExpectedReturnOnPlanAssets	3589000	USD
	us-gaap	Defined Benefit Plan Expected Return On Plan Assets DefinedBenefitPlanExpectedReturnOnPlanAssets	3942000	USD
CY2019Q3	us-gaap	Defined Benefit Plan Amortization Of Prior Service Cost Credit DefinedBenefitPlanAmortizationOfPriorServiceCostCredit	-68000	USD
CY2018Q3	us-gaap	Defined Benefit Plan Amortization Of Prior Service Cost Credit DefinedBenefitPlanAmortizationOfPriorServiceCostCredit	-68000	USD
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	us-gaap	Defined Benefit Plan Amortization Of Prior Service Cost Credit DefinedBenefitPlanAmortizationOfPriorServiceCostCredit	-203000	USD
CY2019Q3	us-gaap	Defined Benefit Plan Amortization Of Gains Losses DefinedBenefitPlanAmortizationOfGainsLosses	-586000	USD
CY2018Q3	us-gaap	Defined Benefit Plan Amortization Of Gains Losses DefinedBenefitPlanAmortizationOfGainsLosses	-592000	USD
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CY2019Q3	us-gaap	Defined Benefit Plan Net Periodic Benefit Cost DefinedBenefitPlanNetPeriodicBenefitCost	546000	USD
CY2018Q3	us-gaap	Defined Benefit Plan Net Periodic Benefit Cost DefinedBenefitPlanNetPeriodicBenefitCost	500000	USD
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	us-gaap	Defined Benefit Plan Net Periodic Benefit Cost DefinedBenefitPlanNetPeriodicBenefitCost	880000	USD
CY2019Q3	us-gaap	Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount	360000	shares
CY2018Q3	us-gaap	Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount	92000	shares
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CY2019Q3	cbsh	Accelerated Share Repurchase Program Repurchase Amount AcceleratedShareRepurchaseProgramRepurchaseAmount	150000000.0	USD
CY2019Q3	cbsh	Shares Received Under Accelerated Share Repurchase Program SharesReceivedUnderAcceleratedShareRepurchaseProgram	1994327	shares
CY2019Q3	cbsh	Percentageof Total Sharestobe Delivered PercentageofTotalSharestobeDelivered	0.75
CY2018Q4	us-gaap	Common Stock Shares Authorized CommonStockSharesAuthorized	120000000	shares
CY2019Q2	us-gaap	Common Stock Shares Authorized CommonStockSharesAuthorized	140000000	shares
CY2018Q4	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	-64669000	USD
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CY2019Q3	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	144173000	USD
CY2017Q4	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	14108000	USD
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CY2018Q3	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	-141596000	USD
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CY2019Q3	cbsh	Number Of Locations NumberOfLocations	165	Locations
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CY2019Q3	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	203512000	USD
CY2019Q3	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	10963000	USD
CY2019Q3	us-gaap	Noninterest Income NoninterestIncome	132743000	USD
CY2019Q3	us-gaap	Gain Loss On Investments GainLossOnInvestments	4909000	USD
CY2019Q3	us-gaap	Noninterest Expense NoninterestExpense	191020000	USD
CY2019Q3	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	139181000	USD
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CY2018Q3	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	207754000	USD
CY2018Q3	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	9999000	USD
CY2018Q3	us-gaap	Noninterest Income NoninterestIncome	123714000	USD
CY2018Q3	us-gaap	Gain Loss On Investments GainLossOnInvestments	4306000	USD
CY2018Q3	us-gaap	Noninterest Expense NoninterestExpense	185059000	USD
CY2018Q3	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	140716000	USD
	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	611605000	USD
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CY2019Q3	us-gaap	Derivative Notional Amount DerivativeNotionalAmount	4178156000	USD
CY2018Q4	us-gaap	Derivative Notional Amount DerivativeNotionalAmount	3254921000	USD
CY2019Q3	us-gaap	Derivative Assets DerivativeAssets	134874000	USD
CY2018Q4	us-gaap	Derivative Assets DerivativeAssets	41210000	USD
CY2019Q3	us-gaap	Derivative Liabilities DerivativeLiabilities	11756000	USD
CY2018Q4	us-gaap	Derivative Liabilities DerivativeLiabilities	13421000	USD
CY2019Q3	us-gaap	Derivative Asset Fair Value Gross Asset Including Not Subject To Master Netting Arrangement DerivativeAssetFairValueGrossAssetIncludingNotSubjectToMasterNettingArrangement	134874000	USD
CY2019Q3	cbsh	Derivative Asset Amount Offset By Liabiilty DerivativeAssetAmountOffsetByLiabiilty	0	USD
CY2019Q3	us-gaap	Derivative Assets DerivativeAssets	134874000	USD
CY2019Q3	us-gaap	Derivative Liability Fair Value Gross Liability Including Not Subject To Master Netting Arrangement DerivativeLiabilityFairValueGrossLiabilityIncludingNotSubjectToMasterNettingArrangement	11756000	USD
CY2019Q3	cbsh	Derivative Liability Amount Offset By Asset DerivativeLiabilityAmountOffsetByAsset	0	USD
CY2019Q3	us-gaap	Derivative Liabilities DerivativeLiabilities	11756000	USD
CY2018Q4	us-gaap	Derivative Asset Fair Value Gross Asset Including Not Subject To Master Netting Arrangement DerivativeAssetFairValueGrossAssetIncludingNotSubjectToMasterNettingArrangement	41210000	USD
CY2018Q4	cbsh	Derivative Asset Amount Offset By Liabiilty DerivativeAssetAmountOffsetByLiabiilty	0	USD
CY2018Q4	us-gaap	Derivative Assets DerivativeAssets	41210000	USD
CY2018Q4	us-gaap	Derivative Liability Fair Value Gross Liability Including Not Subject To Master Netting Arrangement DerivativeLiabilityFairValueGrossLiabilityIncludingNotSubjectToMasterNettingArrangement	13421000	USD
CY2018Q4	cbsh	Derivative Liability Amount Offset By Asset DerivativeLiabilityAmountOffsetByAsset	0	USD
CY2018Q4	us-gaap	Derivative Liabilities DerivativeLiabilities	13421000	USD
CY2019Q3	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	3500000	USD
CY2018Q3	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	3200000	USD
	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	10400000	USD
	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	9600000	USD
CY2018Q4	cbsh	Nonvested Share Awards Balances NonvestedShareAwardsBalances	1180940	shares
CY2018Q4	cbsh	Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Nonvested Share Awards Weighted Average Grant Date Unit Fair Value ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsNonvestedShareAwardsWeightedAverageGrantDateUnitFairValue	43.24
	cbsh	Nonvested Share Awards Granted In Period NonvestedShareAwardsGrantedInPeriod	199252	shares
	cbsh	Share Based Compensation Granted Nonvested Share Award Weighted Average Grant Date Fair Value ShareBasedCompensationGrantedNonvestedShareAwardWeightedAverageGrantDateFairValue	61.57
	cbsh	Nonvested Share Awards Vested In Period NonvestedShareAwardsVestedInPeriod	312122	shares
	cbsh	Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Nonvested Share Awards Vested In Period Weighted Average Grant Date Fair Value ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsNonvestedShareAwardsVestedInPeriodWeightedAverageGrantDateFairValue	33.00
	cbsh	Nonvested Share Awards Forfeited In Period NonvestedShareAwardsForfeitedInPeriod	11894	shares
	cbsh	Share Based Compensation Forfeited Nonvested Share Award Weighted Average Grant Date Fair Value ShareBasedCompensationForfeitedNonvestedShareAwardWeightedAverageGrantDateFairValue	49.17
CY2019Q3	cbsh	Nonvested Share Awards Balances NonvestedShareAwardsBalances	1056176	shares
CY2019Q3	cbsh	Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Nonvested Share Awards Weighted Average Grant Date Unit Fair Value ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsNonvestedShareAwardsWeightedAverageGrantDateUnitFairValue	49.65
	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Grants In Period Weighted Average Grant Date Fair Value ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue	11.92
	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Expected Dividend Rate ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate	0.017
	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Expected Volatility Rate ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate	0.198
	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Risk Free Interest Rate ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate	0.026
	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Fair Value Assumptions Expected Term1 SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1	P6Y
CY2018Q4	cbsh	Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Number ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNumber	1066438	shares
CY2018Q4	cbsh	Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsWeightedAverageExercisePrice	40.22
	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Grants In Period ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod	186943	shares
	cbsh	Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Grants In Period Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageExercisePrice	61.76
	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Forfeited In Period ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod	5383	shares
	cbsh	Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Forfeited In Period Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriodWeightedAverageExercisePrice	52.00
	cbsh	Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Expired In Period ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsExpiredInPeriod	1837	shares
	cbsh	Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Expired In Period Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsExpiredInPeriodWeightedAverageExercisePrice	38.88
	cbsh	Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Exercised In Period ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsExercisedInPeriod	127447	shares
	cbsh	Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Exercised In Period Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsExercisedInPeriodWeightedAverageExercisePrice	34.10
CY2019Q3	cbsh	Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Number ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNumber	1118714	shares
CY2019Q3	cbsh	Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsWeightedAverageExercisePrice	44.47
	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Outstanding Weighted Average Remaining Contractual Terms ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsOutstandingWeightedAverageRemainingContractualTerms	P6Y8M12D
CY2019Q3	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Equity Instruments Other Than Options Aggregate Intrinsic Value Outstanding SharebasedCompensationArrangementBySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsAggregateIntrinsicValueOutstanding	18310000	USD
	cbsh	Percentof Revenuenotinscopeof Asc606 PercentofRevenuenotinscopeofASC606	0.62	Rate
CY2019Q3	us-gaap	Noninterest Income NoninterestIncome	132743000	USD
CY2018Q3	us-gaap	Noninterest Income NoninterestIncome	123714000	USD
	us-gaap	Noninterest Income NoninterestIncome	381242000	USD
	us-gaap	Noninterest Income NoninterestIncome	368254000	USD
CY2019Q3	us-gaap	Mortgages Held For Sale Fair Value Disclosure MortgagesHeldForSaleFairValueDisclosure	14393000	USD
CY2019Q3	us-gaap	Financial Instruments Owned Us Government And Agency Obligations At Fair Value FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue	849877000	USD
CY2019Q3	cbsh	Us Government Sponsored Enterprises Debt Securities USGovernmentSponsoredEnterprisesDebtSecurities	168817000	USD
CY2019Q3	us-gaap	Financial Instruments Owned State And Municipal Government Obligations At Fair Value FinancialInstrumentsOwnedStateAndMunicipalGovernmentObligationsAtFairValue	1203495000	USD
CY2019Q3	cbsh	Financial Instruments Owned Agency Mortgage Backed Securities At Fair Value FinancialInstrumentsOwnedAgencyMortgageBackedSecuritiesAtFairValue	3858575000	USD
CY2019Q3	cbsh	Financial Instruments Owned Non Agency Mortgage Backed Securities At Fair Value FinancialInstrumentsOwnedNonAgencyMortgageBackedSecuritiesAtFairValue	936577000	USD
CY2019Q3	cbsh	Other Asset Backed Securities Disclosure OtherAssetBackedSecuritiesDisclosure	1298835000	USD
CY2019Q3	cbsh	Financial Instruments Owned Other Debt Securities At Fair Value FinancialInstrumentsOwnedOtherDebtSecuritiesAtFairValue	344243000	USD
CY2019Q3	us-gaap	Trading Securities TradingSecurities	35918000	USD
CY2019Q3	us-gaap	Equity Securities Fv Ni EquitySecuritiesFvNi	2902000	USD
CY2019Q3	us-gaap	Financial Instruments Owned Principal Investments At Fair Value FinancialInstrumentsOwnedPrincipalInvestmentsAtFairValue	93441000	USD
CY2019Q3	us-gaap	Derivative Assets DerivativeAssets	134874000	USD
CY2019Q3	us-gaap	Deferred Compensation Plan Assets DeferredCompensationPlanAssets	15571000	USD
CY2019Q3	us-gaap	Assets Fair Value Disclosure AssetsFairValueDisclosure	8957518000	USD
CY2019Q3	us-gaap	Derivative Liabilities DerivativeLiabilities	11756000	USD
CY2019Q3	us-gaap	Deferred Compensation Liability Current And Noncurrent DeferredCompensationLiabilityCurrentAndNoncurrent	15571000	USD
CY2019Q3	us-gaap	Liabilities Fair Value Disclosure LiabilitiesFairValueDisclosure	27327000	USD
CY2018Q4	us-gaap	Mortgages Held For Sale Fair Value Disclosure MortgagesHeldForSaleFairValueDisclosure	13529000	USD
CY2018Q4	us-gaap	Financial Instruments Owned Us Government And Agency Obligations At Fair Value FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue	907652000	USD
CY2018Q4	cbsh	Us Government Sponsored Enterprises Debt Securities USGovernmentSponsoredEnterprisesDebtSecurities	195778000	USD
CY2018Q4	us-gaap	Financial Instruments Owned State And Municipal Government Obligations At Fair Value FinancialInstrumentsOwnedStateAndMunicipalGovernmentObligationsAtFairValue	1328039000	USD
CY2018Q4	cbsh	Financial Instruments Owned Agency Mortgage Backed Securities At Fair Value FinancialInstrumentsOwnedAgencyMortgageBackedSecuritiesAtFairValue	3214985000	USD
CY2018Q4	cbsh	Financial Instruments Owned Non Agency Mortgage Backed Securities At Fair Value FinancialInstrumentsOwnedNonAgencyMortgageBackedSecuritiesAtFairValue	1047716000	USD
CY2018Q4	cbsh	Other Asset Backed Securities Disclosure OtherAssetBackedSecuritiesDisclosure	1511614000	USD
CY2018Q4	cbsh	Financial Instruments Owned Other Debt Securities At Fair Value FinancialInstrumentsOwnedOtherDebtSecuritiesAtFairValue	332257000	USD
CY2018Q4	us-gaap	Trading Securities TradingSecurities	27059000	USD
CY2018Q4	us-gaap	Equity Securities Fv Ni EquitySecuritiesFvNi	2585000	USD
CY2018Q4	us-gaap	Financial Instruments Owned Principal Investments At Fair Value FinancialInstrumentsOwnedPrincipalInvestmentsAtFairValue	85659000	USD
CY2018Q4	us-gaap	Derivative Assets DerivativeAssets	41210000	USD
CY2018Q4	us-gaap	Deferred Compensation Plan Assets DeferredCompensationPlanAssets	12968000	USD
CY2018Q4	us-gaap	Assets Fair Value Disclosure AssetsFairValueDisclosure	8721051000	USD
CY2018Q4	us-gaap	Derivative Liabilities DerivativeLiabilities	13421000	USD
CY2018Q4	us-gaap	Deferred Compensation Liability Current And Noncurrent DeferredCompensationLiabilityCurrentAndNoncurrent	12968000	USD
CY2018Q4	us-gaap	Liabilities Fair Value Disclosure LiabilitiesFairValueDisclosure	26389000	USD
CY2019Q2	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Value FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue	98935000	USD
CY2019Q3	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Gain Loss Included In Earnings1 FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInEarnings1	-1945000	USD
CY2019Q3	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Gain Loss Included In Other Comprehensive Income Loss FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInOtherComprehensiveIncomeLoss	-65000	USD
CY2019Q3	cbsh	Investment Securities Called InvestmentSecuritiesCalled	-1715000	USD
CY2019Q3	cbsh	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Discount Accretion FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetDiscountAccretion	36000	USD
CY2019Q3	cbsh	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Purchase Of Private Equity Securities FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPurchaseOfPrivateEquitySecurities	5010000	USD
CY2019Q3	cbsh	Purchase Of Risk Participation Agreement PurchaseOfRiskParticipationAgreement	200000	USD
CY2019Q3	cbsh	Sale Of Risk Participation Agreement SaleOfRiskParticipationAgreement	241000	USD
CY2019Q3	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Value FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue	104105000	USD
CY2019Q3	cbsh	Change In Unrealized Gains Or Losses Related To Assets Held Level3 Fair Value Measurements ChangeInUnrealizedGainsOrLossesRelatedToAssetsHeldLevel3FairValueMeasurements	2880000	USD
CY2018Q4	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Value FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue	100307000	USD
	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Gain Loss Included In Earnings1 FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInEarnings1	633000	USD
	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Gain Loss Included In Other Comprehensive Income Loss FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInOtherComprehensiveIncomeLoss	294000	USD
	cbsh	Investment Securities Called InvestmentSecuritiesCalled	-4635000	USD
	cbsh	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Discount Accretion FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetDiscountAccretion	80000	USD
	cbsh	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Purchase Of Private Equity Securities FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPurchaseOfPrivateEquitySecurities	14899000	USD
	cbsh	Sales And Repayments Of Private Equity Securities SalesAndRepaymentsOfPrivateEquitySecurities	6150000	USD
	cbsh	Capitalized Interest Or Dividends CapitalizedInterestOrDividends	31000	USD
	cbsh	Purchase Of Risk Participation Agreement PurchaseOfRiskParticipationAgreement	226000	USD
	cbsh	Sale Of Risk Participation Agreement SaleOfRiskParticipationAgreement	314000	USD
CY2019Q3	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Value FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue	104105000	USD
	cbsh	Change In Unrealized Gains Or Losses Related To Assets Held Level3 Fair Value Measurements ChangeInUnrealizedGainsOrLossesRelatedToAssetsHeldLevel3FairValueMeasurements	-1532000	USD
CY2018Q2	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Value FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue	84697000	USD
CY2018Q3	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Gain Loss Included In Earnings1 FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInEarnings1	-4217000	USD
CY2018Q3	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Gain Loss Included In Other Comprehensive Income Loss FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInOtherComprehensiveIncomeLoss	167000	USD
CY2018Q3	cbsh	Investment Securities Sold InvestmentSecuritiesSold	-518000	USD
CY2018Q3	cbsh	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Discount Accretion FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetDiscountAccretion	7000	USD
CY2018Q3	cbsh	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Purchase Of Private Equity Securities FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPurchaseOfPrivateEquitySecurities	10407000	USD
CY2018Q3	cbsh	Purchase Of Risk Participation Agreement PurchaseOfRiskParticipationAgreement	50000	USD
CY2018Q3	cbsh	Sale Of Risk Participation Agreement SaleOfRiskParticipationAgreement	31000	USD
CY2018Q3	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Value FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue	98996000	USD
CY2018Q3	cbsh	Change In Unrealized Gains Or Losses Related To Assets Held Level3 Fair Value Measurements ChangeInUnrealizedGainsOrLossesRelatedToAssetsHeldLevel3FairValueMeasurements	4947000	USD
CY2017Q4	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Value FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue	73271000	USD
	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Gain Loss Included In Earnings1 FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInEarnings1	-12642000	USD
	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Gain Loss Included In Other Comprehensive Income Loss FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInOtherComprehensiveIncomeLoss	-79000	USD
	cbsh	Investment Securities Sold InvestmentSecuritiesSold	-2233000	USD
	cbsh	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Discount Accretion FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetDiscountAccretion	25000	USD
	cbsh	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Purchase Of Private Equity Securities FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPurchaseOfPrivateEquitySecurities	15650000	USD
	cbsh	Sales And Repayments Of Private Equity Securities SalesAndRepaymentsOfPrivateEquitySecurities	186000	USD
	cbsh	Capitalized Interest Or Dividends CapitalizedInterestOrDividends	35000	USD
	cbsh	Purchase Of Risk Participation Agreement PurchaseOfRiskParticipationAgreement	50000	USD
	cbsh	Sale Of Risk Participation Agreement SaleOfRiskParticipationAgreement	179000	USD
CY2018Q3	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Value FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue	98996000	USD
	cbsh	Change In Unrealized Gains Or Losses Related To Assets Held Level3 Fair Value Measurements ChangeInUnrealizedGainsOrLossesRelatedToAssetsHeldLevel3FairValueMeasurements	13223000	USD
CY2019Q3	cbsh	Total Gains Or Losses Included In Earnings Level3 Fair Measurements TotalGainsOrLossesIncludedInEarningsLevel3FairMeasurements	1945000	USD
CY2019Q3	cbsh	Change In Unrealized Gains Or Losses Related To Assets Held Level3 Fair Value Measurements ChangeInUnrealizedGainsOrLossesRelatedToAssetsHeldLevel3FairValueMeasurements	2880000	USD
	cbsh	Total Gains Or Losses Included In Earnings Level3 Fair Measurements TotalGainsOrLossesIncludedInEarningsLevel3FairMeasurements	12642000	USD
	cbsh	Change In Unrealized Gains Or Losses Related To Assets Held Level3 Fair Value Measurements ChangeInUnrealizedGainsOrLossesRelatedToAssetsHeldLevel3FairValueMeasurements	13223000	USD
	cbsh	Total Gains Or Losses Included In Earnings Level3 Fair Measurements TotalGainsOrLossesIncludedInEarningsLevel3FairMeasurements	-633000	USD
	cbsh	Change In Unrealized Gains Or Losses Related To Assets Held Level3 Fair Value Measurements ChangeInUnrealizedGainsOrLossesRelatedToAssetsHeldLevel3FairValueMeasurements	-1532000	USD
CY2018Q3	cbsh	Total Gains Or Losses Included In Earnings Level3 Fair Measurements TotalGainsOrLossesIncludedInEarningsLevel3FairMeasurements	4217000	USD
CY2018Q3	cbsh	Change In Unrealized Gains Or Losses Related To Assets Held Level3 Fair Value Measurements ChangeInUnrealizedGainsOrLossesRelatedToAssetsHeldLevel3FairValueMeasurements	4947000	USD
CY2019Q3	cbsh	Loans Nonrecurring Basis LoansNonrecurringBasis	171000	USD
	cbsh	Loans Nonrecurring Basis Gains Losses LoansNonrecurringBasisGainsLosses	-139000	USD
CY2019Q3	cbsh	Mortgage Servicing Rights Nonrecurring Basis MortgageServicingRightsNonrecurringBasis	7235000	USD
	cbsh	Mortgage Servicing Rights Nonrecurring Basis Gains Losses MortgageServicingRightsNonrecurringBasisGainsLosses	-404000	USD
CY2019Q3	cbsh	Long Lived Assets Nonrecurring Basis LongLivedAssetsNonrecurringBasis	820000	USD
	cbsh	Long Lived Assets Nonrecurring Basis Gains Losses LongLivedAssetsNonrecurringBasisGainsLosses	-318000	USD
CY2018Q3	cbsh	Loans Nonrecurring Basis LoansNonrecurringBasis	230000	USD
	cbsh	Loans Nonrecurring Basis Gains Losses LoansNonrecurringBasisGainsLosses	-197000	USD
CY2018Q3	cbsh	Mortgage Servicing Rights Nonrecurring Basis MortgageServicingRightsNonrecurringBasis	6008000	USD
	cbsh	Mortgage Servicing Rights Nonrecurring Basis Gains Losses MortgageServicingRightsNonrecurringBasisGainsLosses	9000	USD
CY2018Q3	cbsh	Long Lived Assets Nonrecurring Basis LongLivedAssetsNonrecurringBasis	2319000	USD
	cbsh	Long Lived Assets Nonrecurring Basis Gains Losses LongLivedAssetsNonrecurringBasisGainsLosses	-858000	USD

Files In Submission

Name	View Source	Status
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$CBSH
COMMERCE BANCSHARES INC /MO/ Stock $cbsh

2019 Q4 Form 10-Q Financial Statement

#000002235619000043 Filed on November 04, 2019

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$CBSH COMMERCE BANCSHARES INC /MO/ Stock $cbsh

2019 Q4 Form 10-Q Financial Statement

#000002235619000043 Filed on November 04, 2019

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$CBSH
COMMERCE BANCSHARES INC /MO/ Stock $cbsh