Stock Repurchase Program - Summary of Stock Repurchase Activity (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	1 Months Ended		12 Months Ended
	Jun. 30, 2015	Jan. 31, 2015	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Equity, Class of Treasury Stock [Line Items]
Shares Repurchased (in shares)			59
Value of Shares Repurchased			$ 2,100
Shares Repurchased, Remaining Amount Authorized
Beginning balance		$ 985	985
Repurchases of shares of common stock			(2,149)	$ (4,658)	$ (1,343)
Ending balance			1,836	$ 985
Stock Repurchase Program January 2015
Shares Repurchased, Remaining Amount Authorized
Authorization of additional plan		$ 2,000	$ 2,000
Shares Repurchase Prior To The Distribution
Equity, Class of Treasury Stock [Line Items]
Shares Repurchased (in shares)			18
Average Price per Share (in usd per share)			$ 56.95
Value of Shares Repurchased			$ 1,000
Shares Repurchased, Remaining Amount Authorized
Repurchases of shares of common stock			(1,000)
Stock Repurchase Program June 2015
Shares Repurchased, Remaining Amount Authorized
Authorization of additional plan	$ 1,000		$ 1,000
Shares Repurchase Subsequent To The Distribution
Equity, Class of Treasury Stock [Line Items]
Shares Repurchased (in shares)			41
Average Price per Share (in usd per share)			$ 27.48
Value of Shares Repurchased			$ 1,149
Shares Repurchased, Remaining Amount Authorized
Repurchases of shares of common stock			$ (1,149)