Stockholders' Equity - Additional Information (Details) - USD ($)	3 Months Ended				9 Months Ended
	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Jul. 30, 2014
Equity [Abstract]
Dividends declared per common share	$ 0.06	$ 0.06	$ 0.05	$ 0.05	$ 0.17	$ 0.15
Stock Repurchase Program, Authorized Amount							$ 1,400,000,000
Repurchases of common stock					$ 245,000,000	$ 181,000,000
Shares repurchased during period					12,482,277
Stock Repurchase Program, Remaining Authorized Repurchase Amount	$ 66,000,000				$ 66,000,000