Advances and Other Receivables, Net - Advances and Other Receivables Roll Forward (Details) - Reserves for Advances and Other Receivables - 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
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance - beginning of period		$ 0
Provision and other additions		20
Write-offs		0
Balance - end of period	$ 0	20		$ 0
Predecessor
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance - beginning of period	294	$ 297	$ 236	284	$ 184
Provision and other additions	7		30	69	106
Write-offs	(4)		(13)	(56)	(37)
Balance - end of period	$ 297		$ 253	$ 297	$ 253