Segment Results (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014 item	Jun. 30, 2013
Segment Results
Number of reportable segments			3
Earnings Summary:
Net interest income	$ 219,102	$ 202,919	$ 418,900	$ 403,992
(Reversal of) provision for credit losses on loans and leases, excluding covered loans	(1,000)		(1,000)
(Reversal of) provision for losses on covered loans	(1,461)	(11,927)	3,194	(2,035)
Noninterest income	101,099	82,209	202,347	175,737
Depreciation and amortization	9,339	10,180	18,654	20,284
Noninterest expense	216,283	201,249	421,861	402,485
Income before income taxes	97,040	85,626	178,538	158,995
Provision for income taxes	29,829	25,422	56,117	46,683
Net income	67,211	60,204	122,421	112,312
Less: Net income attributable to noncontrolling interest	510	463	1,209	1,048
Net income attributable to City National Corporation	66,701	59,741	121,212	111,264
Selected Average Balances:
Loans and leases, excluding covered loans	17,959,191	15,434,102	17,650,520	15,123,447
Covered loans	643,690	909,728	669,781	949,370
Total assets	29,978,947	27,469,581	29,704,180	27,588,708
Deposits	25,912,081	23,118,818	25,643,332	22,766,840
Goodwill	642,622	642,622	642,622	642,622
Customer-relationship intangibles, net	38,470	45,375	39,258	46,337
Other segment
Earnings Summary:
Net interest income	10,215	17,632	19,894	34,410
Noninterest income	(9,298)	(6,818)	(20,357)	(19,006)
Depreciation and amortization	4,799	4,680	9,546	9,265
Noninterest expense	(20,780)	(18,725)	(40,003)	(35,465)
Income before income taxes	16,898	24,859	29,994	41,604
Provision for income taxes	5,221	7,420	9,492	12,297
Net income	11,677	17,439	20,502	29,307
Net income attributable to City National Corporation	11,677	17,439	20,502	29,307
Selected Average Balances:
Loans and leases, excluding covered loans	57,683	54,730	56,353	54,691
Total assets	10,579,781	10,313,532	10,554,566	10,695,626
Deposits	254,272	588,957	243,238	527,035
Commercial and Private Banking
Earnings Summary:
Net interest income	208,413	185,040	398,206	369,017
(Reversal of) provision for credit losses on loans and leases, excluding covered loans	(1,000)		(1,000)
(Reversal of) provision for losses on covered loans	(1,461)	(11,927)	3,194	(2,035)
Noninterest income	40,926	30,555	89,140	80,818
Depreciation and amortization	2,774	3,624	5,595	7,243
Noninterest expense	179,904	171,254	351,972	342,201
Income before income taxes	69,122	52,644	127,585	102,426
Provision for income taxes	21,360	15,715	40,375	30,273
Net income	47,762	36,929	87,210	72,153
Net income attributable to City National Corporation	47,762	36,929	87,210	72,153
Selected Average Balances:
Loans and leases, excluding covered loans	17,901,508	15,379,372	17,594,167	15,068,756
Covered loans	643,690	909,728	669,781	949,370
Total assets	18,705,693	16,503,312	18,473,951	16,244,521
Deposits	25,584,025	22,409,159	25,319,356	22,126,242
Goodwill	393,177	393,177	393,177	393,177
Customer-relationship intangibles, net	2,692	5,176	2,912	5,543
Wealth Management
Earnings Summary:
Net interest income	474	247	800	565
Noninterest income	69,471	58,472	133,564	113,925
Depreciation and amortization	1,766	1,876	3,513	3,776
Noninterest expense	57,159	48,720	109,892	95,749
Income before income taxes	11,020	8,123	20,959	14,965
Provision for income taxes	3,248	2,287	6,250	4,113
Net income	7,772	5,836	14,709	10,852
Less: Net income attributable to noncontrolling interest	510	463	1,209	1,048
Net income attributable to City National Corporation	7,262	5,373	13,500	9,804
Selected Average Balances:
Total assets	693,473	652,737	675,663	648,561
Deposits	73,784	120,702	80,738	113,563
Goodwill	249,445	249,445	249,445	249,445
Customer-relationship intangibles, net	$ 35,778	$ 40,199	$ 36,346	$ 40,794