Income Taxes (Detail) - USD ($)	3 Months Ended	12 Months Ended
Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2020
Operating Loss Carryforwards [Line Items]
Effective tax rate (percentage)	1300.00%	0.00%
Discrete income tax benefit	$ 152,000,000	$ 0
Discrete tax benefit related to intra-entity asset transfer	157,000,000
Tax expense related to equity compensation vesting	6,000,000
Income tax benefit	182,000,000	0
Pre-tax net loss	$ 14,000,000	$ 10,000,000
Scenario, Forecast
Operating Loss Carryforwards [Line Items]
Effective tax rate (percentage)			4800.00%

Discrete Income Tax Expense (Benefit)

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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 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 the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to deductions. Including, but not limited to, extraterritorial income exclusion deduction, qualified production activity deduction, dividend deduction, deduction for dividend paid to employee stock ownership plan, Medicare prescription drug benefit subsidy deduction, and other deductions.

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Amount of reported income tax expense (benefit) in excess of (less than) expected income tax expense (benefit) computed by applying domestic federal statutory income tax rate to pretax income (loss) from continuing operation, attributable to nondeductible expense for award under share-based payment arrangement. Includes, but is not limited to, expense determined to be nondeductible upon grant or after for award under share-based payment arrangement.

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