Stockholders' Equity - Additional Information (Detail) - USD ($)		1 Months Ended		3 Months Ended		9 Months Ended
	Oct. 06, 2016	Sep. 30, 2015	Mar. 31, 2015	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015		Aug. 05, 2015	Jul. 31, 2015	Aug. 31, 2007
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock repurchase program, number of shares authorized to be repurchased												20,000,000
Treasury stock value				$ 1,470,200,000		$ 1,470,200,000		$ 1,265,700,000	[1]
Common stock in treasury, shares				33,984,569		33,984,569		29,612,337
Subsequent Event [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Dividends declared date	Oct. 06, 2016
Dividends declared payable date	Dec. 16, 2016
Dividends declared date of record	Dec. 02, 2016
Dividends per share on common stock	$ 0.16
Common Stock Repurchase Set Two | Share Trading Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Treasury stock value					$ 277,200,000		$ 401,800,000
Number of common stock shares repurchased					5,539,803		8,164,237
Common Stock Repurchase Set One | Share Trading Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Treasury stock value				$ 165,000,000		$ 217,000,000
Number of common stock shares repurchased				3,545,828		4,680,313
Accelerated Shares Repurchase Agreement [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Treasury stock value		$ 298,700,000	$ 25,000,000		$ 298,700,000		$ 298,700,000
Common stock in treasury, shares		5,771,603	546,574		5,771,603		5,771,603
Common stock repurchase price per share		$ 51.76	$ 45.74
Maximum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock repurchase program, authorized amount											$ 1,500,000,000
Maximum [Member] | Accelerated Shares Repurchase Agreement [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Treasury stock value										$ 300,000,000

[1] As of January 1, 2016, we have adopted ASU 2015-03 and ASU 2015-15 with retrospective application. This resulted in a reclassification from other non-current assets to long-term debt, less current portion for debt issuance costs as of December 31, 2015. Refer to Note 2, “Recently Issued Accounting Standards” of the notes to the condensed consolidated financial statements for further details.