Reorganization Adjustments - Equity Value (Details) - USD ($) $ in Millions	Sep. 30, 2020	Jul. 01, 2019
Fresh-Start Adjustment [Line Items]
Enterprise Value	$ 3,100	$ 3,100
Plus: Total cash		125
Less: Pension obligations		239
Total equity (deficit)		1,156
Continuing Operations
Fresh-Start Adjustment [Line Items]
Enterprise Value		3,100
Plus: Total cash		125
Less: Fair value of new debt		(1,646)
Less: Fair value of remaining debt obligations		(184)
Less: Pension obligations		(239)
Total equity (deficit)		1,156
Plus: Fair value of noncontrolling interest		1
Paid-in capital (Successor)		$ 1,157