Consolidated Statement of Comprehensive Income (Loss) (Parenthetical) (Unaudited) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Tax Effect [Abstract]
Other Comprehensive Income, Unrealized Gain (Loss) on Derivatives Arising During Period, Tax	$ 0	$ 0	$ (1)	$ 0
Other Comprehensive Income Loss Reclassification Adjustment On Derivatives Included In Net Income Tax	0	0	0	0
Other Comprehensive Income (Loss), Tax [Abstract]
Foreign currency translation adjustments, taxes	0	3	0	(12)
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Tax [Abstract]
Amortization of prior service cost (credit) included in net periodic benefit cost, taxes	1	1	1	1
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net Unamortized Gain (Loss) Arising During Period, Tax	0	2	0	2
Amortization of actuarial (gain) loss included in net periodic benefit cost, taxes	$ (2)	$ (3)	$ (5)	$ (6)