Regulatory Capital Requirements (Tables)

12 Months Ended

Dec. 31, 2011

Regulatory Capital Requirements [Abstract]

Schedule Of Capital Amounts And Ratios On Consolidated Basis

	Actual				Minimum Capital Requirement				Well-Capitalized Capital Requirement
(Dollars in thousands)	Amount		Ratio		Amount		Ratio		Amount		Ratio
December 31, 2011
Total Capital (to risk-weightedassets):
Commerce Bancshares, Inc. (consolidated)	$	2,103,401	16.04	%	$	1,049,221	8.00	%	N.A.		N.A.
Commerce Bank	1,840,952		14.19		1,037,636		8.00		$	1,297,045	10.00	%
Tier I Capital (to risk-weightedassets):
Commerce Bancshares, Inc. (consolidated)	$	1,928,690	14.71	%	$	524,610	4.00	%	N.A.		N.A.
Commerce Bank	1,678,530		12.94		518,818		4.00		$	778,227	6.00	%
Tier I Capital (to adjusted quarterly average assets):
(Leverage Ratio)
Commerce Bancshares, Inc. (consolidated)	$	1,928,690	9.55	%	$	807,839	4.00	%	N.A.		N.A.
Commerce Bank	1,678,530		8.36		802,709		4.00		$	1,003,386	5.00	%
December 31, 2010
Total Capital (to risk-weightedassets):
Commerce Bancshares, Inc. (consolidated)	$	2,002,646	15.75	%	$	1,017,429	8.00	%	N.A.		N.A.
Commerce Bank	1,762,382		14.03		1,004,781		8.00		$	1,255,977	10.00	%
Tier I Capital (to risk-weightedassets):
Commerce Bancshares, Inc. (consolidated)	$	1,828,965	14.38	%	$	508,715	4.00	%	N.A.		N.A.
Commerce Bank	1,604,873		12.78		502,391		4.00		$	753,586	6.00	%
Tier I Capital (to adjusted quarterly average assets):
(Leverage Ratio)
Commerce Bancshares, Inc. (consolidated)	$	1,828,965	10.17	%	$	719,411	4.00	%	N.A.		N.A.
Commerce Bank	1,604,873		9.00		713,230		4.00		$	891,538	5.00	%