Interest Expense (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Interest Income (Expense), Net [Abstract]
Interest expense	$ 258	$ 268	$ 830	$ 577
Interest income	(5)	(7)	(14)	(15)
Interest expense, net	$ 253	$ 261	$ 816	$ 562