Shareholders' Equity Additional Information (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended				1 Months Ended	0 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2000	Apr. 30, 2010	Jan. 29, 2015
Stockholders Equity Note [Line Items]
Cash dividends declared, per share	$ 1.92	$ 1.68	$ 1.48
Repurchase and retirement of common stock, shares	554,000	4,337,000	1,649,000
Repurchase and retirement of common stock	$ 81,812	$ 530,033	$ 127,525
Remaining authorized repurchase amount	1,050,000
Employee Stock Purchase Plan Number Of Shares Available For Issuance	3,000,000
Share Based Compensation Arrangements By Share Based Payment Award Percentage Of Market Price At Eligible Employees Granted Options To Purchase Shares	95.00%
Stock Issued During Period, Shares, Employee Stock Purchase Plans	1,261,000
Common stock excluded from calculation of diluted earnings per share	581,000	23,000	872,000
Maximum
Stockholders Equity Note [Line Items]
Number of shares authorized to be repurchased	75,000,000
Stockholder Rights Plan [Member]
Stockholders Equity Note [Line Items]
Minimum Percentage Of Ownership Acquired Or To Be Acquired Upon Which Purchase Rights Become Exercisable				15.00%
Common Stock Dividends Right Per Share Declared				1
Dividends Payable, Date of Record				Jun. 01, 2000
Incentive Stock Purchase Rights Redemption Price Per Right					$ 0.01
Stockholder Rights Plan [Member] | Maximum
Stockholders Equity Note [Line Items]
Common Stock Price Per Share Under Rights Plan					$ 125
Stockholder Rights Plan [Member] | Minimum
Stockholders Equity Note [Line Items]
Common Stock Price Per Share Under Rights Plan					$ 75
Fuji Heavy Industries Ltd. [Member]
Stockholders Equity Note [Line Items]
Repurchase and retirement of common stock, shares	3,960,000
Repurchase and retirement of common stock	$ 497,474
Subsequent Event
Stockholders Equity Note [Line Items]
Cash dividends declared, per share						$ 0.53
Remaining authorized repurchase amount						1,100,000