Stockholder's Equity - Additional Information (Detail) (USD $) In Millions, except Per Share data, unless otherwise specified	1 Months Ended	6 Months Ended	1 Months Ended
	Mar. 31, 2014	Jun. 30, 2014	Mar. 31, 2014 Senior Subordinated Convertible Notes	Feb. 28, 2014 Maximum
Stockholders' Equity [Line Items]
Repurchase of common stock, authorized value				$ 500
Net proceeds from senior subordinated convertible notes used for repurchase of common stock			163
Repurchase of common stock, shares	2.7	3.5
Per share average price of shares repurchased	$ 60.65
Stock repurchase, amount paid		$ 208