Income Taxes (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2019
(Provision) Benefit for Income Taxes	$ (22)	$ (25)	$ (80)	$ (75)
Loss Before Income Taxes	$ (172)	$ (226)	$ (615)	$ (784)
Forecast
Uncertain tax positions, estimated for next twelve months					$ 19

Amount of income (loss) from continuing operations, including income (loss) from equity method investments, before deduction of income tax expense (benefit), and income (loss) attributable to noncontrolling interest.

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