Stockholders' Equity - Schedule of Shares Repurchase Plans (Details) - USD ($) $ / shares in Units, shares in Millions	12 Months Ended
	Dec. 31, 2015	Mar. 31, 2015
Equity, Class of Treasury Stock [Line Items]
Stock repurchased during period (shares)	20.5
Average cost of share acquired (USD per share)	$ 74.07
Shares repurchased during period	$ 1,520,000,000
2015 Program
Equity, Class of Treasury Stock [Line Items]
Amount of common stock authorized for repurchase	$ 1,800,000,000.00	$ 1,800,000,000.00
Stock repurchased during period (shares)	14.2
Average cost of share acquired (USD per share)	$ 73.72
Shares repurchased during period	$ 1,050,000,000
Remaining authorized repurchase amount	780,000,000
2014 Program
Equity, Class of Treasury Stock [Line Items]
Amount of common stock authorized for repurchase	$ 1,700,000,000.0
Stock repurchased during period (shares)	6.3
Average cost of share acquired (USD per share)	$ 74.88
Shares repurchased during period	$ 470,000,000
Remaining authorized repurchase amount	$ 0