Income Taxes (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Income Tax Disclosure [Abstract]
Income tax expense	$ 12	$ 33	$ 56	$ 45
Loss before income taxes	567	$ 279	1,481	$ 744
Tax Credit Carryforward, Valuation Allowance	20		20
Unrecognized Tax Benefits	210		210
Decrease in Unrecognized Tax Benefits is Reasonably Possible	$ 2		$ 2

Amount of decrease reasonably possible in the next twelve months for the unrecognized tax benefit.

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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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Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

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Amount of valuation allowance pertaining to the deferred tax asset representing potential future taxable deductions from tax credit carryforwards for which it is more likely than not that a tax benefit will not be realized.

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Amount of unrecognized tax benefits.

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