Interest Expense, Net (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Interest Expense
Interest expense	$ 250	$ 258	$ 759	$ 830
Interest income	(5)	(5)	(15)	(14)
Interest expense), net	$ 245	$ 253	$ 744	$ 816