Share-Based Compensation (Details) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2013 plan	Jun. 30, 2012	Jun. 30, 2013 plan	Jun. 30, 2012
Share-Based Compensation
Number of share-based compensation plans	1		1
Compensation cost recognized for share-based awards	$ 5,400,000	$ 4,300,000	$ 10,500,000	$ 9,000,000
Total income tax benefit recognized for share-based compensation arrangements	2,300,000	1,800,000	4,400,000	3,800,000
Cash received from the exercise of stock options			17,838,000	9,044,000
Actual tax benefit realized for the tax deductions from stock option exercises			3,500,000	900,000
Share-based compensation, fair value
Shares available for future grants	3,300,000		3,300,000
Amended and Restated City National Corporation 2008 Omnibus Plan
Share-based compensation
Granted (in shares)			0
Stock options
Share-based compensation, fair value
Weighted-average volatility (as a percent)			28.12%	30.58%
Dividend yield (as a percent)			2.15%	2.14%
Expected term			6 years 1 month 24 days	6 years 1 month 10 days
Risk-free interest rate (as a percent)			1.24%	1.44%
Weighted-average grant-date fair values of options granted (in dollars per share)			$ 12.57	$ 11.64
Total intrinsic value of options exercised			$ 8,500,000	$ 2,100,000