Income Taxes - Narrative (Details) - USD ($) $ in Millions	2 Months Ended	3 Months Ended		10 Months Ended	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Oct. 31, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Components of Income Tax Expense (Benefit) [Line Items]
Tax Cuts and Jobs Act, provisional tax expense	$ 195				$ 195
Effective income tax rate	251.60%
Net deferred tax assets	$ 214				214
Deferred tax liabilities, noncurrent	212				212
Deferred tax assets, noncurrent	426				426
Increase in operating loss carryforwards					1,000
Deferred tax assets, valuation allowance	942				942
Valuation allowance increase (decrease)					80
Unrecognized tax benefits that would impact effective tax rate	20				20
Unrecognized tax benefits, accrued interest	20				20
Decrease in unrecognized tax benefits is reasonably possible	3				3
Foreign jurisdiction
Components of Income Tax Expense (Benefit) [Line Items]
Operating loss carryforwards	5,800				5,800
Tax credits	15				15
U.S. Internal Revenue Service (IRS)
Components of Income Tax Expense (Benefit) [Line Items]
Operating loss carryforwards	9,900				9,900
State jurisdiction
Components of Income Tax Expense (Benefit) [Line Items]
Operating loss carryforwards	$ 10,000				$ 10,000
Predecessor
Components of Income Tax Expense (Benefit) [Line Items]
Effective income tax rate				38.70%		19.60%	(1113.00%)
Income tax expense (benefit) from change in valuation allowances						$ 82	$ 3,300
Net deferred tax assets		$ 3,122				3,122
Deferred tax liabilities, noncurrent		248				248
Deferred tax assets, noncurrent		3,370				3,370
Deferred tax assets, valuation allowance		862				862
Effective income tax rate reconciliation, share-based compensation, excess tax benefit, amount						22
Effective income tax rate reconciliation, federal law changes		110
Unrecognized tax benefits that would impact effective tax rate		17		$ 19		17
Unrecognized tax benefits, accrued interest		$ 18				18
Predecessor | Geographic distribution, foreign
Components of Income Tax Expense (Benefit) [Line Items]
Recognized income tax benefit						82
Predecessor | Foreign jurisdiction
Components of Income Tax Expense (Benefit) [Line Items]
Recognized income tax benefit						$ 110
Predecessor | U.S. Internal Revenue Service (IRS)
Components of Income Tax Expense (Benefit) [Line Items]
Recognized income tax benefit			$ 3,300
Deferred income tax expense (benefit)			$ 3,100