Reclassifications from Accumulated Other Comprehensive Income (Loss) (Components of Accumulated Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	$ 2,362	$ 1,979	$ 917
Other comprehensive loss before reclassifications	(5)
Amounts reclassified from other comprehensive income	8
Net current-period other comprehensive income	3	8	(5)
Ending balance	3,246	2,362	1,979
Accumulated Other Comprehensive Income (Loss)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(36)	(44)	(39)
Net current-period other comprehensive income	3	8	(5)
Ending balance	(33)	(36)	$ (44)
Pension and Other Postretirement
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(22)
Other comprehensive loss before reclassifications	(5)
Amounts reclassified from other comprehensive income	8
Net current-period other comprehensive income	3
Ending balance	(19)	(22)
Foreign Currency
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(14)
Other comprehensive loss before reclassifications	0
Amounts reclassified from other comprehensive income	0
Net current-period other comprehensive income	0
Ending balance	$ (14)	$ (14)

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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Amount after tax, before reclassification adjustments, of other comprehensive income (loss), attributable to parent.

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Amount after tax of other comprehensive income (loss) attributable to parent entity.

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Amount after tax of reclassification adjustments of other comprehensive income (loss) attributable to parent.

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Total of all stockholders' equity (deficit) items, net of receivables from officers, directors, owners, and affiliates of the entity which are attributable to the parent. The amount of the economic entity's stockholders' equity attributable to the parent excludes the amount of stockholders' equity which is allocable to that ownership interest in subsidiary equity which is not attributable to the parent (noncontrolling interest, minority interest). This excludes temporary equity and is sometimes called permanent equity.

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