Income Taxes Income Taxes - Narrative (Details) - USD ($) $ in Millions	3 Months Ended		4 Months Ended	7 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017	Mar. 31, 2018
Successor [Member]
Operating Loss Carryforwards [Line Items]
Tax Cuts and Jobs Act of 2017, Incomplete Accounting, Change in Tax Rate, Provisional Income Tax Expense (Benefit)	$ 48			$ (2,668)
Tax Cuts and Jobs Act of 2017, Incomplete Accounting, Transition Tax for Accumulated Foreign Earnings, Provisional Income Tax Expense			$ 715
Tax Cuts and Jobs Act of 2017, Indirect Impact on Inventory, Income Tax Expense	$ 16
Predecessor [Member]
Operating Loss Carryforwards [Line Items]
Tax benefit related to reduction in company's unrecognized tax benefits		$ 57
Pre tax benefit on associated accrued interest reversals		50
Continuing Operations [Member] | Predecessor [Member]
Operating Loss Carryforwards [Line Items]
Tax benefit related to reduction in company's unrecognized tax benefits		53
Pre tax benefit on associated accrued interest reversals		47
Discontinued Operations [Member] | Predecessor [Member]
Operating Loss Carryforwards [Line Items]
Tax benefit related to reduction in company's unrecognized tax benefits		4
Pre tax benefit on associated accrued interest reversals		$ 3