Interest Expense, Net (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Interest Expense
Interest expense	$ 251	$ 284	$ 509	$ 572
Interest income	(4)	(4)	(10)	(9)
Interest expense), net	$ 247	$ 280	$ 499	$ 563