Segment Results (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012 segment	Jun. 30, 2011
Segment Results
Number of reportable segments			3
Earnings Summary:
Net interest income	$ 216,479	$ 190,827	$ 417,192	$ 372,117
Provision for credit losses on loans and leases, excluding covered loans	1,000		1,000
Provision for losses on covered loans	13,293	1,716	20,759	20,832
Noninterest income	74,768	91,937	150,468	185,830
Depreciation and amortization	9,531	9,008	18,845	17,924
Noninterest expense	184,985	202,824	376,391	391,305
Income before income taxes	82,438	69,216	150,665	127,886
Provision (benefit) for income taxes	27,271	20,650	48,990	38,536
Net income	55,167	48,566	101,675	89,350
Less: Net income attributable to noncontrolling interest	409	1,095	652	2,187
Net income attributable to City National Corporation	54,758	47,471	101,023	87,163
Selected Average Balances:
Loans and leases, excluding covered loans	13,125,867	11,515,989	12,779,080	11,386,657
Covered loans	1,341,041	1,770,377	1,389,877	1,790,569
Total assets	24,362,546	22,009,749	24,003,722	21,695,572
Deposits	20,948,246	18,784,448	20,582,821	18,485,669
Goodwill	533,146	486,397	509,914	486,623
Customer-relationship intangibles, net	33,843	40,675	34,671	41,012
Commercial and Private Banking
Earnings Summary:
Net interest income	184,768	181,034	356,568	353,719
Provision for credit losses on loans and leases, excluding covered loans	1,000		1,000
Provision for losses on covered loans	13,293	1,716	20,759	20,832
Noninterest income	50,311	60,121	97,555	123,332
Depreciation and amortization	3,414	3,654	6,996	7,287
Noninterest expense	165,834	178,690	337,322	344,195
Income before income taxes	51,538	57,095	88,046	104,737
Provision (benefit) for income taxes	21,646	23,980	36,979	43,990
Net income	29,892	33,115	51,067	60,747
Net income attributable to City National Corporation	29,892	33,115	51,067	60,747
Selected Average Balances:
Loans and leases, excluding covered loans	13,073,029	11,453,329	12,726,026	11,326,163
Covered loans	1,341,041	1,770,377	1,389,877	1,790,569
Total assets	14,728,913	13,733,704	14,433,156	13,634,595
Deposits	20,379,604	18,348,651	20,050,801	18,051,444
Goodwill	370,333	324,762	347,547	324,985
Customer-relationship intangibles, net	8,129	12,511	8,568	12,461
Wealth Management
Earnings Summary:
Net interest income	649	531	1,265	1,099
Noninterest income	39,966	41,065	79,337	82,941
Depreciation and amortization	1,538	1,498	2,984	2,947
Noninterest expense	36,102	39,551	72,191	77,735
Income before income taxes	2,975	547	5,427	3,358
Provision (benefit) for income taxes	1,078	(6)	2,006	940
Net income	1,897	553	3,421	2,418
Less: Net income attributable to noncontrolling interest	409	562	652	1,120
Net income attributable to City National Corporation	1,488	(9)	2,769	1,298
Selected Average Balances:
Total assets	530,179	553,839	533,956	553,547
Deposits	96,839	61,393	97,937	54,020
Goodwill	162,813	161,635	162,367	161,638
Customer-relationship intangibles, net	25,714	28,164	26,103	28,551
Other
Earnings Summary:
Net interest income	31,062	9,262	59,359	17,299
Noninterest income	(15,509)	(9,249)	(26,424)	(20,443)
Depreciation and amortization	4,579	3,856	8,865	7,690
Noninterest expense	(16,951)	(15,417)	(33,122)	(30,625)
Income before income taxes	27,925	11,574	57,192	19,791
Provision (benefit) for income taxes	4,547	(3,324)	10,005	(6,394)
Net income	23,378	14,898	47,187	26,185
Less: Net income attributable to noncontrolling interest		533		1,067
Net income attributable to City National Corporation	23,378	14,365	47,187	25,118
Selected Average Balances:
Loans and leases, excluding covered loans	52,838	62,660	53,054	60,494
Total assets	9,103,454	7,722,206	9,036,610	7,507,430
Deposits	$ 471,803	$ 374,404	$ 434,083	$ 380,205