Price Risk Management Activities, Hedging Instruments by Consolidated Balance Sheet Location (Details) - USD ($) $ in Millions	Jun. 30, 2021	Dec. 31, 2020
Derivatives Designated as Hedging Instruments [Member] | Commodity Contracts [Member] | Receivable, Net [Member]
Fair Values of Derivative Instruments
Derivative asset, fair value, gross asset	$ 6	$ 4
Derivative asset, fair value, gross liability	16	17
Derivatives Not Designated as Hedging Instruments [Member]
Fair Values of Derivative Instruments
Derivative asset, fair value, gross asset	603	412
Derivative liability, fair value, gross liability	597	392
Derivatives Not Designated as Hedging Instruments [Member] | Commodity Contracts [Member] | Receivable, Net [Member]
Fair Values of Derivative Instruments
Derivative asset, fair value, gross asset	558	399
Derivative asset, fair value, gross liability	587	388
Derivatives Not Designated as Hedging Instruments [Member] | Physical Purchase Contracts [Member] | Inventories [Member]
Fair Values of Derivative Instruments
Derivative asset, fair value, gross asset	37	13
Derivative asset, fair value, gross liability	1	0
Derivatives Not Designated as Hedging Instruments [Member] | Foreign Currency Contracts [Member] | Receivable, Net [Member]
Fair Values of Derivative Instruments
Derivative asset, fair value, gross asset	8	0
Derivative asset, fair value, gross liability	0	0
Derivatives Not Designated as Hedging Instruments [Member] | Foreign Currency Contracts [Member] | Accrued Expenses [Member]
Fair Values of Derivative Instruments
Derivative liability, fair value, gross asset	0	0
Derivative liability, fair value, gross liability	$ 9	$ 4