Accounts Receivable (Narrative) (Details) - USD ($) $ in Millions	1 Months Ended	3 Months Ended	4 Months Ended	6 Months Ended
Apr. 30, 2021	Jun. 30, 2020	Apr. 30, 2021	Jun. 30, 2020
Predecessor [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Provision for uncollectible amounts	$ 4	$ 10	$ 14	$ 24

Amount of expense (reversal of expense) for expected credit loss on accounts receivable.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 13
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=121599337&loc=SL82919249-210447

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03(5))
-URI http://asc.fasb.org/extlink&oid=120395209&loc=SL114868664-224227

Name:	us-gaap_ProvisionForDoubtfulAccounts
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration