Chapter 11 Filing And Other Related Matters (Schedule Of Liabilities Subject To Compromise) (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Chapter 11 Filing And Other Related Matters [Abstract]
Accounts payable	$ 57
Other current liabilities	62
Accounts payable and other current liabilities	119
Debt subject to compromise	10,949
Accrued interest on debt subject to compromise	497
Long-term debt and accrued interest	11,446
Liabilities subject to compromise	$ 11,565

The amount of trade accounts payable included in liabilities subject to compromise.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 852
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=120604989&loc=d3e56015-112765

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 852
-SubTopic 10
-Section 45
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=116635682&loc=d3e55717-112764

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 852
-SubTopic 10
-Section 55
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=84165509&loc=d3e56145-112766

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