Segment Results (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Segment Results
Number of reportable segments			3
Earnings Summary:
Net interest income	$ 190,827	$ 181,998	$ 372,117	$ 357,503
Provision for credit losses on loans and leases, excluding covered loans		32,000		87,000
Provision for losses on covered loans	1,716	46,516	20,832	46,516
Noninterest income	91,937	122,636	185,830	199,509
Depreciation and amortization	9,008	8,491	17,924	17,285
Noninterest expense	202,824	178,196	391,305	345,336
Income before income taxes	69,216	39,431	127,886	60,875
Provision (benefit) for income taxes	20,650	(2,859)	38,536	1,559
Net income	48,566	42,290	89,350	59,316
Less: Net income attributable to noncontrolling interest	1,095	972	2,187	2,300
Net income attributable to City National Corporation	47,471	41,318	87,163	57,016
Selected Average Balances:
Loans and leases, excluding covered loans	11,515,989	11,581,920	11,386,657	11,762,122
Covered loans	1,770,377	2,002,893	1,790,569	1,918,481
Total assets	22,009,749	20,799,187	21,695,572	20,534,687
Deposits	18,784,448	17,600,298	18,485,669	17,234,260
Goodwill	486,397	479,982	486,623	479,982
Customer-relationship intangibles, net	40,675	42,329	41,012	43,585
Commercial and Private Banking
Earnings Summary:
Net interest income	187,589	172,875	366,521	341,863
Provision for credit losses on loans and leases, excluding covered loans		32,000		87,000
Provision for losses on covered loans	1,716	46,516	20,832	46,516
Noninterest income	59,693	100,022	123,054	146,557
Depreciation and amortization	3,654	3,403	7,287	6,717
Noninterest expense	178,353	156,082	343,608	301,549
Income before income taxes	63,559	34,896	117,848	46,638
Provision (benefit) for income taxes	26,695	14,657	49,496	19,588
Net income	36,864	20,239	68,352	27,050
Net income attributable to City National Corporation	36,864	20,239	68,352	27,050
Selected Average Balances:
Loans and leases, excluding covered loans	11,453,329	11,542,673	11,326,163	11,724,323
Covered loans	1,770,377	2,002,893	1,790,569	1,918,481
Total assets	13,733,704	14,201,015	13,634,595	14,343,237
Deposits	18,348,651	16,963,504	18,051,444	16,604,189
Goodwill	324,762	318,340	324,985	318,340
Customer-relationship intangibles, net	12,511	11,407	12,461	12,041
Wealth Management
Earnings Summary:
Net interest income	541	372	1,099	705
Noninterest income	41,065	40,178	82,941	80,251
Depreciation and amortization	1,498	1,528	2,947	3,485
Noninterest expense	39,888	37,016	78,322	72,442
Income before income taxes	220	2,006	2,771	5,029
Provision (benefit) for income taxes	(144)	659	694	1,595
Net income	364	1,347	2,077	3,434
Less: Net income attributable to noncontrolling interest	562	437	1,120	1,230
Net income attributable to City National Corporation	(198)	910	957	2,204
Selected Average Balances:
Total assets	553,839	556,826	553,547	552,468
Deposits	61,393	48,171	54,020	47,771
Goodwill	161,635	161,642	161,638	161,642
Customer-relationship intangibles, net	28,164	30,922	28,551	31,544
Other.
Earnings Summary:
Net interest income	2,697	8,751	4,497	14,935
Noninterest income	(8,821)	(17,564)	(20,165)	(27,299)
Depreciation and amortization	3,856	3,560	7,690	7,083
Noninterest expense	(15,417)	(14,902)	(30,625)	(28,655)
Income before income taxes	5,437	2,529	7,267	9,208
Provision (benefit) for income taxes	(5,901)	(18,175)	(11,654)	(19,624)
Net income	11,338	20,704	18,921	28,832
Less: Net income attributable to noncontrolling interest	533	535	1,067	1,070
Net income attributable to City National Corporation	10,805	20,169	17,854	27,762
Selected Average Balances:
Loans and leases, excluding covered loans	62,660	39,247	60,494	37,799
Total assets	7,722,206	6,041,346	7,507,430	5,638,982
Deposits	$ 374,404	$ 588,623	$ 380,205	$ 582,300