Stockholders' Equity - Schedule of Shares Repurchase Plans (Details) - USD ($) $ / shares in Units, shares in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2015
Equity, Class of Treasury Stock [Line Items]
Stock repurchased during period (shares)	4.7	16.8
Average cost of share acquired (USD per share)		$ 61.68
Shares repurchased during period	$ 325,000,000	$ 1,040,000,000
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)	0.0	12.1
Average cost of share acquired (USD per share)	$ 0.00	$ 58.83
Shares repurchased during period	$ 0	$ 715,000,000
2016 Program
Equity, Class of Treasury Stock [Line Items]
Amount of common stock authorized for repurchase			$ 1,400,000,000.0
Stock repurchased during period (shares)	4.7	4.7
Average cost of share acquired (USD per share)	$ 69.03	$ 69.03
Shares repurchased during period	$ 325,000,000	$ 325,000,000