Fair Value of Financial Instruments Unobservable Input Reconciliation (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance as of the beginning of the period	$ 58	$ 151	$ 137	$ 97
Net realized and unrealized (gains)/losses	11	(17)	(72)	39
Fair Value, Measurement with Unobservable Inputs Reconciliation, Liability, Transfers Into Level 3	(15)
Transfers out of Level 3 to Level 2		0	(11)	(2)
Balance as of the end of the period	$ 54	$ 134	$ 54	$ 134

Net Liabilities From Price Risk Management Activities Classified as Level 3

No definition available.

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- Definition

Realized and Unrealized Gains and Losses, Net, Commodity Contracts

+ References

No definition available.

+ Details

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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- Definition

Amount of transfers of financial instrument classified as a liability into level 3 of the fair value hierarchy.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(3)
-URI http://asc.fasb.org/extlink&oid=123874694&loc=d3e19207-110258

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- Definition

Amount of transfers of financial instrument classified as a liability out of level 3 of the fair value hierarchy.

+ References

+ Details

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