Parent Company Condensed Financial Statements (Condensed Statements Of Income) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Interest and dividends on investment securities	$ 313,892	$ 236,278	$ 216,793
Salaries and employee benefits	554,047	525,248	512,987
Data processing fees paid to affiliates	110,692	101,792	95,325
Other	73,634	73,613	57,429
Total non-interest expense	848,777	805,901	768,378
Income tax expense (benefit)	132,358	145,711	87,293
NET INCOME ATTRIBUTABLE TO COMMERCE BANCSHARES, INC.	488,399	530,765	354,057
Commerce Bancshares, Inc. (Parent) [Member]
Dividends received from consolidated subsidiary banks	300,001	340,001	210,001
Earnings of consolidated subsidiaries, net of dividends	203,965	200,461	148,435
Interest and dividends on investment securities	2,480	2,162	1,802
Management fees charged subsidiaries	38,632	36,310	33,472
Investment securities gains (losses)	(872)	79	53
Net interest income on advances and note to subsidiaries	1,403	51	233
Other	3,709	2,927	4,282
Total income	549,318	581,991	398,278
Salaries and employee benefits	44,352	37,362	31,277
Professional fees	2,740	2,006	1,977
Data processing fees paid to affiliates	3,173	2,834	2,765
Other	15,595	12,973	11,850
Total non-interest expense	65,860	55,175	47,869
Income tax expense (benefit)	(4,941)	(3,949)	(3,648)
NET INCOME ATTRIBUTABLE TO COMMERCE BANCSHARES, INC.	$ 488,399	$ 530,765	$ 354,057