Subsequent Events (Details) - USD ($) $ / shares in Units, shares in Millions			3 Months Ended
	May 02, 2018	Jan. 30, 2018	Mar. 31, 2018	Mar. 31, 2017	Feb. 28, 2018	Jan. 31, 2018
Subsequent Event [Line Items]
Cash dividends declared per common stock (in dollars per share)		$ 0.18	$ 0.18	$ 0.10
Stock repurchase program, remaining authorized repurchase amount			$ 1,300,000,000
Stock Repurchase Program, Authorized Amount						$ 2,000,000,000.0
Subsequent Event
Subsequent Event [Line Items]
Cash dividends declared per common stock (in dollars per share)	$ 0.18
Accelerated Share Repurchase Program
Subsequent Event [Line Items]
Shares settled (in shares)			23.3
Amount repurchased			$ 600,000,000
Stock Repurchase Program, Authorized Amount					$ 750,000,000	$ 750,000,000