Consolidated Statements Of Comprehensive Income (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Net income	$ 271,439	$ 259,623	$ 221,875
Available for sale debt securities for which a portion of an other-than-temporary impairment (OTTI) has been recorded in earnings:
Unrealized holding gains subsequent to initial OTTI recognition	12,203	5,184	22,973
Income tax expense	(4,637)	(1,970)	(8,730)
Net unrealized gains on OTTI securities	7,566	3,214	14,243
Other available for sale investment securities:
Unrealized holding gains	39,271	78,059	6,412
Income tax expense on unrealized gains	(14,927)	(29,663)	(2,470)
Reclassification adjustment for gains included in net income	(357)	(177)	(3,488)
Reclassification adjustment for tax expense on gains included in net income	139	68	1,359
Net unrealized gains on other securities	24,126	48,287	1,813
Prepaid pension cost:
Amortization of accumulated pension loss	2,953	1,949	2,208
Net loss arising during period	(12,447)	(8,898)	(786)
Income tax (expense) benefit on change in pension loss	3,608	2,641	(540)
Change in pension loss	(5,886)	(4,308)	882
Other comprehensive income	25,806	47,193	16,938
Comprehensive income	297,245	306,816	238,813
Non-controlling interest expense	(2,110)	(3,280)	(165)
Comprehensive income attributable to Commerce Bancshares, Inc.	$ 295,135	$ 303,536	$ 238,648