Fair Value Measurements (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2021	Dec. 31, 2020
Embedded derivatives
Impairment and related charges, net of tax	$ 135
Recurring \| Accrued liabilities
Embedded derivatives
Netting and Collateral	0	$ 0
Recurring \| Accrued liabilities \| Total Fair Value
Embedded derivatives
Embedded derivatives	32	64
Recurring \| Accrued liabilities \| Level 1
Embedded derivatives
Embedded derivatives	0	0
Recurring \| Accrued liabilities \| Level 2
Embedded derivatives
Embedded derivatives	32	64
Recurring \| Accrued liabilities \| Level 3
Embedded derivatives
Embedded derivatives	$ 0	$ 0

Fair value of asset associated with financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset, and right to receive cash collateral under master netting arrangements.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=99393222&loc=SL20226003-175313

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 50
-Paragraph 3
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 45
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=117331979&loc=d3e41228-113958

Name:	us-gaap_DerivativeLiabilityFairValueGrossAssetAndRightToReclaimCashOffset
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant