Other Items (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Net Interest and Other Financing [Abstract]
Interest income	$ 9	$ 7	$ 5
Interest expense(a)	(358)	(309)	(319)
Income on interest rate swaps	11	12	9
Interest capitalized	26	20	12
Total interest	(312)	(270)	(293)
Net foreign currency gains (losses)	23	21	14
Other	22	11	1
Total other	45	32	15
Net interest and other	(267)	(238)	(278)
Aggregate foreign currency gains losses [Abstract]
Net interest and other	23	21	14
Provision for income taxes	(11)	(12)	(2)
Aggregate foreign currency gains (losses)	$ 12	$ 9	$ 12