Income Taxes - Schedule of Income Taxes (Details) - USD ($) $ in Millions	1 Months Ended	2 Months Ended	3 Months Ended	7 Months Ended	9 Months Ended
	Jul. 31, 2018	Sep. 30, 2018	Sep. 30, 2017	Jul. 31, 2018	Sep. 30, 2017
Income Tax Contingency [Line Items]
Income tax (benefit) expense		$ (979)
Effective tax rate		(2377.10%)
Predecessor
Income Tax Contingency [Line Items]
Income tax (benefit) expense	$ (19)		$ 5	$ 48	$ (4)
Effective tax rate	23.10%		37.10%	23.80%	29.10%