Fresh Start Adjustments - Narrative (Details) - USD ($) $ in Millions	Dec. 31, 2020	Sep. 30, 2020	Dec. 31, 2019	Jul. 01, 2019
Fresh-Start Adjustment [Line Items]
Favorable leasehold interest	$ 8		$ 9
Fresh start adjustment, Trademark				$ 141
Fresh-Start adjustment, Technology based intangible				110
Discontinued Operations
Fresh-Start Adjustment [Line Items]
Fresh Start Items, Right of Use Assets				1
Favorable leasehold interest		$ 5
Continuing Operations
Fresh-Start Adjustment [Line Items]
Fresh Start Items, Right of Use Assets				24
Favorable leasehold interest		$ 9
Continuing Operations | Predecessor Company [Member]
Fresh-Start Adjustment [Line Items]
Fresh start adjustment, Customer Related Intangibles				$ 904