Supplemental Financial Information Supplemental Financial Information - Other (Expense) Income (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Other (Expense) Income [Abstract]
Interest and Other Income	$ 3	$ 4	$ 5
Foreign currency fluctuations and foreign exchange contracts	(26)	(40)	(21)
Divestiture and liquidation losses	0	(6)	(34)
Other, net	(8)	(8)	(7)
Total other (expense), net	$ (31)	$ (50)	$ (57)