Income Taxes Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2019	Mar. 31, 2018
Income Tax Disclosure [Abstract]
Income tax (benefit) expense	$ 6	$ 17
Income (loss) from continuing operations before income tax benefit (expense)	$ (658)	$ 384
Effective income tax rate	(0.90%)	4.40%
Statutory federal income tax rate	21.00%	21.00%

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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