Income Taxes (Provision) (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2021	Mar. 31, 2020
Income Taxes
Effective tax rate	17.80%	1.10%
Income tax benefit	$ (21)	$ (4)
Various discrete tax items expense (benefit)	$ (27)	$ (20)
Annual effective tax rate excluding discrete items (as a percent)	(5.70%)	(9.50%)

Percentage of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations, excluding discrete items.

No definition available.

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

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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 increase (decrease) to previously recorded tax expense. Includes, but is not limited to, significant settlements of income tax disputes, and unusual tax positions or infrequent actions taken by the entity, including tax assessment reversal, and IRS tax settlement.

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