Consolidated Statements Of Income (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
INTEREST INCOME
Interest and fees on loans	$ 439,082	$ 446,331	$ 463,511
Interest on loans held for sale	176	361	1,115
Interest on investment securities	189,415	211,682	219,348
Interest on short-term federal funds sold and securities purchased under agreements to resell	106	82	55
Interest on long-term securities purchased under agreements to resell	21,119	19,174	13,455
Interest on deposits with banks	387	339	487
Total interest income	650,285	677,969	697,971
INTEREST EXPENSE
Savings, interest checking and money market	14,355	18,682	25,856
Time open and C.D.’s of less than $100,000	6,002	7,918	11,352
Time open and C.D.’s of $100,000 and over	6,383	7,174	9,272
Interest on federal funds purchased and securities sold under agreements to repurchase	809	808	1,741
Interest on other borrowings	3,364	3,481	3,680
Total interest expense	30,913	38,063	51,901
Net interest income	619,372	639,906	646,070
Provision for loan losses	20,353	27,287	51,515
Net interest income after provision for loan losses	599,019	612,619	594,555
NON-INTEREST INCOME
Bank card transaction fees	166,627	154,197	157,077
Trust fees	102,529	94,679	88,313
Deposit account charges and other fees	79,017	79,485	82,651
Capital market fees	14,133	21,066	19,846
Consumer brokerage services	11,006	10,162	10,018
Loan fees and sales	5,865	6,037	7,580
Other	39,209	34,004	27,432
Total non-interest income	418,386	399,630	392,917
INVESTMENT SECURITIES GAINS (LOSSES), NET
Change in fair value of other-than-temporary impairment securities	278	11,223	2,190
Portion recognized in other comprehensive income	(1,562)	(12,713)	(4,727)
Net impairment losses	(1,284)	(1,490)	(2,537)
Realized gains on sales and fair value adjustments	(3,141)	6,318	13,349
Investment securities gains (losses), net	(4,425)	4,828	10,812
NON-INTEREST EXPENSE
Salaries and employee benefits	366,867	360,899	345,325
Net occupancy	45,639	45,534	46,434
Equipment	18,425	20,147	22,252
Supplies and communication	22,511	22,321	22,448
Data processing and software	78,245	73,798	68,103
Marketing	14,176	15,106	16,767
Deposit insurance	11,167	10,438	13,123
Debit overdraft litigation	0	0	18,300
Other	72,603	70,226	64,497
Total non-interest expense	629,633	618,469	617,249
Income before income taxes	383,347	398,608	381,035
Less income taxes	122,230	127,169	121,412
Net income	261,117	271,439	259,623
Less non-controlling interest expense	156	2,110	3,280
NET INCOME ATTRIBUTABLE TO COMMERCE BANCSHARES, INC.	$ 260,961	$ 269,329	$ 256,343
Net income per common share - basic (in dollars per share)	$ 2.73	$ 2.77	$ 2.57
Net income per common share - diluted (in dollars per share)	$ 2.72	$ 2.76	$ 2.56