Consolidated Statements Of Income (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
INTEREST INCOME
Interest and fees on loans	$ 447,157	$ 439,082	$ 446,331
Interest on loans held for sale	0	176	361
Interest on investment securities	188,006	189,415	211,682
Interest on short-term federal funds sold and securities purchased under agreements to resell	101	106	82
Interest on long-term securities purchased under agreements to resell	12,473	21,119	19,174
Interest on deposits with banks	555	387	339
Total interest income	648,292	650,285	677,969
INTEREST EXPENSE
Savings, interest checking and money market	13,522	14,355	18,682
Time open and C.D.’s of less than $100,000	4,137	6,002	7,918
Time open and C.D.’s of $100,000 and over	5,926	6,383	7,174
Interest on federal funds purchased and securities sold under agreements to repurchase	1,019	809	808
Interest on other borrowings	3,484	3,364	3,481
Total interest expense	28,088	30,913	38,063
Net interest income	620,204	619,372	639,906
Provision for loan losses	29,531	20,353	27,287
Net interest income after provision for loan losses	590,673	599,019	612,619
NON-INTEREST INCOME
Bank card transaction fees	175,806	166,627	154,197
Trust fees	112,158	102,529	94,679
Deposit account charges and other fees	78,680	79,017	79,485
Capital market fees	12,667	14,133	21,066
Consumer brokerage services	12,006	11,006	10,162
Loan fees and sales	5,108	5,865	6,037
Other	39,553	39,209	34,004
Total non-interest income	435,978	418,386	399,630
INVESTMENT SECURITIES GAINS (LOSSES), NET
Change in fair value of other-than-temporary impairment securities	(2,091)	278	11,223
Portion recognized in other comprehensive income	726	(1,562)	(12,713)
Net impairment losses	(1,365)	(1,284)	(1,490)
Realized gains on sales and fair value adjustments	15,489	(3,141)	6,318
Investment securities gains (losses), net	14,124	(4,425)	4,828
NON-INTEREST EXPENSE
Salaries and employee benefits	384,100	366,867	360,899
Net occupancy	45,825	45,639	45,534
Equipment	18,375	18,425	20,147
Supplies and communication	22,432	22,511	22,321
Data processing and software	78,980	78,245	73,798
Marketing	15,676	14,176	15,106
Deposit insurance	11,622	11,167	10,438
Other	80,765	72,603	70,226
Total non-interest expense	657,775	629,633	618,469
Income before income taxes	383,000	383,347	398,608
Less income taxes	120,216	122,230	127,169
Net income	262,784	261,117	271,439
Less non-controlling interest expense	1,030	156	2,110
NET INCOME ATTRIBUTABLE TO COMMERCE BANCSHARES, INC.	261,754	260,961	269,329
Preferred Stock Dividends, Income Statement Impact	4,050	0	0
Net Income (Loss) Available to Common Stockholders, Basic	$ 257,704	$ 260,961	$ 269,329
Net income per common share - basic (in dollars per share)	$ 2.62	$ 2.60	$ 2.64
Net income per common share - diluted (in dollars per share)	$ 2.61	$ 2.59	$ 2.63