Stockholders’ Equity - Summary of Stock Repurchase Activity (Details) $ / shares in Units, $ in Millions	3 Months Ended
	Mar. 31, 2017 USD ($) $ / shares shares
Equity [Abstract]
Shares Repurchased | shares	10,000,000
Average Price per Share (in usd per share) | $ / shares	$ 33.65
Value of Shares Repurchased	$ 350
Shares Repurchased, Remaining Amount Authorized
Beginning balance	1,336
Repurchase of shares of common stock	(350)
Ending balance	$ 986
Treasury shares retired | shares	0