Stockholders' Equity - Additional Information (Detail) - USD ($) $ / shares in Units, shares in Millions	1 Months Ended	3 Months Ended	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2015	Jun. 30, 2015	Mar. 31, 2015
Disclosure - Stockholders' Equity - Additional Information (Detail) [Line Items]
Common stock issued as a result of option exercises			0.3
Value of shares authorized to repurchase program				$ 750,000,000
Shares repurchased		1.2	2.8
Average price per share for common shares repurchased		$ 84.24	$ 80.91
Total cost of common shares repurchased		$ 105,000,000	$ 228,000,000
Remaining capacity for authorized repurchase shares	$ 601,000,000	$ 601,000,000	601,000,000
Dividends paid	$ 64,000,000		$ 128,000,000
Dividends paid per share	$ 0.375		$ 0.75
Dividends record date	Jun. 08, 2015
Maximum [Member]
Disclosure - Stockholders' Equity - Additional Information (Detail) [Line Items]
Common stock issued as a result of option exercises		0.1