Fresh Start Accounting (Fresh Start - Net Cash Payments) (Details) - USD ($) $ in Millions	Dec. 31, 2021	Apr. 30, 2021
Successor [Member]
Cash and Cash Equivalents, at Carrying Value, Total	$ 2,127	$ 890
Reorganization Adjustments [Member]
Cash and Cash Equivalents, at Carrying Value, Total		(1,169)
Reorganization Adjustments [Member] | Successor [Member]
Net proceeds from Incremental Exit Term Loan Facility		220
Release of restricted cash from other assets to cash		8
Total sources		228
Payments of Excess to Unsecured senior notes holders		(1,313)
Payments of pre-petition accounts payable and contract cure payments		(62)
Payments of professional fees and other bankruptcy related costs		(22)
Total uses		(1,397)
Cash and Cash Equivalents, at Carrying Value, Total		$ (1,169)