Fresh Start Accounting (Fresh Start - Cumulative Impact Of Reorganization) (Details) $ in Millions	Apr. 30, 2021 USD ($)
Fresh Start Accounting [Abstract]
Gain on settlement of Liabilities Subject to Compromise	$ 5,274
Cancellation of Predecessor equity	4,754
Net impact on accumulated deficit	$ 10,028

Amount of fresh-start adjustment to retained earnings or deficit.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 852
-SubTopic 10
-Section 55
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=84165509&loc=d3e56426-112766

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 852
-SubTopic 10
-Section 45
-Paragraph 21
-URI http://asc.fasb.org/extlink&oid=116635682&loc=d3e55811-112764

Name:	us-gaap_FreshStartAdjustmentIncreaseDecreaseRetainedEarningsDeficit
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant