Other Items (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Net Interest and Other Financing [Abstract]
Interest income	$ 14	$ 9	$ 7
Interest expense(a)	(402)	(358)	(309)
Income on interest rate swaps	13	11	12
Interest capitalized	23	26	20
Total interest	(352)	(312)	(270)
Net foreign currency gains (losses)	2	23	21
Other Nonoperating Expense	15	22	11
Total other	17	45	32
Net interest and other	(335)	(267)	(238)
Aggregate foreign currency gains losses [Abstract]
Net interest and other	2	23	21
Provision for income taxes	(32)	(11)	(12)
Aggregate foreign currency gains (losses)	$ (30)	$ 12	$ 9