Derivative Instruments (Movements out of OCI) (Details) - Foreign Exchange Contract [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Derivative [Line Items]
Foreign currency transaction gains (losses)	$ (19)	$ (3)	$ (7)
Cost of sales
Derivative [Line Items]
Foreign currency transaction gains (losses)	0	19	1
Other income (expense), net
Derivative [Line Items]
Foreign currency transaction gains (losses)	$ (19)	$ (22)	$ (8)