Stockholders' Equity - Schedule of Shares Repurchase Plans (Details) - USD ($) $ / shares in Units, shares in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2016	Mar. 31, 2015
2016 Program
Equity, Class of Treasury Stock [Line Items]
Amount of common stock authorized for repurchase	$ 1,400,000,000.0	$ 1,400,000,000.0
2015 Program
Equity, Class of Treasury Stock [Line Items]
Amount of common stock authorized for repurchase			$ 1,800,000,000.00
Stock repurchased during period (shares)	6.5	12.1
Average cost of share acquired (USD per share)	$ 59.66	$ 58.83
Shares repurchased during period	$ 390,000,000	$ 715,000,000