Parent Company Condensed Financial Statements (Narrative) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Investments in marketable common and preferred stock	$ 6,210,000	$ 7,153,000
Commerce Bancshares, Inc. (Parent) [Member]
Note receivable due from bank subsidiary	50,000,000	50,000,000
Parent's line of credit facility with the Bank, maximum borrowing capacity	20,000,000
Financial Instruments Owned Corporate Bonds	5,200,000
Investments in marketable common and preferred stock	6,000,000
Equity Securities without Readily Determinable Fair Value, Amount	5,100,000
Parent line of credit with Bank, borrowings during period	$ 0	$ 0	$ 0