Common Stock Repurchase Program - Additional Information (Detail) - USD ($) $ / shares in Units, shares in Millions	1 Months Ended		3 Months Ended
	Feb. 28, 2017	Nov. 30, 2016	Mar. 31, 2016	Dec. 31, 2016
Stock Repurchase Program [Line Items]
Cash paid for repurchase of common stock			$ 250,000,000
Maximum capital allocated for repurchases of shares				$ 750,000,000
Accelerated Share Repurchase Agreement (ASR) [Member]
Stock Repurchase Program [Line Items]
Common stock repurchases		$ 225,000,000
Shares of common stock received under ASR	0.4	2.8
Cash paid for repurchase of common stock		$ 225,000,000
Accelerated share repurchase, price per share		$ 63.41
Accelerated Share Repurchase Agreement (ASR) [Member] | Weighted Average [Member]
Stock Repurchase Program [Line Items]
Final weighted average per share purchase price during the repurchase period	$ 69.43