Income Taxes - Narrative (Details) - USD ($)	2 Months Ended	10 Months Ended	12 Months Ended
	Dec. 31, 2017	Oct. 31, 2017	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Components of Income Tax Expense (Benefit) [Line Items]
Tax Cuts and Jobs Act, provisional tax expense				$ 92,000,000	$ 195,000,000
Purchase accounting adjustment				$ (92,000,000)
Effective income tax rate	251.60%	38.70%	(8.60%)	36.50%
Unfavorable impact of non-deductible goodwill impairment			$ 779,000,000
Net deferred tax assets			89,000,000	$ 306,000,000
Deferred tax liabilities, noncurrent			241,000,000	202,000,000
Deferred tax assets, noncurrent			330,000,000	508,000,000
Increase in operating loss carryforwards					1,000,000,000.0
Uncertain tax benefits	$ 21,000,000		952,000,000	970,000,000	$ 21,000,000
Deferred tax assets, valuation allowance			892,000,000	931,000,000
Unrecognized tax benefits that would impact effective tax rate			30,000,000	23,000,000
Unrecognized tax benefits, accrued interest			8,000,000	$ 6,000,000
Reasonably possible decrease in unrecognized tax benefits for uncertain tax positions previously taken			3,000,000
Domestic Tax Authority
Components of Income Tax Expense (Benefit) [Line Items]
Operating loss carryforwards			12,900,000,000
Uncertain tax benefits			4,300,000,000
State jurisdiction
Components of Income Tax Expense (Benefit) [Line Items]
Operating loss carryforwards			9,200,000,000
Foreign jurisdiction
Components of Income Tax Expense (Benefit) [Line Items]
Operating loss carryforwards			$ 6,000,000,000.0