Price Risk Management Activities, Hedging Instruments by Consolidated Balance Sheet Location (Details) - USD ($) $ in Millions	Jun. 30, 2020	Dec. 31, 2019
Derivatives Designated as Hedging Instruments [Member] | Commodity Contracts [Member] | Receivable, Net [Member]
Fair Values of Derivative Instruments
Derivative asset, fair value, gross asset	$ 5	$ 9
Derivative asset, fair value, gross liability	14	20
Derivatives Not Designated as Hedging Instruments [Member]
Fair Values of Derivative Instruments
Derivative asset, fair value, gross asset	680	635
Derivative liability, fair value, gross liability	516	661
Derivatives Not Designated as Hedging Instruments [Member] | Commodity Contracts [Member] | Receivable, Net [Member]
Fair Values of Derivative Instruments
Derivative asset, fair value, gross asset	651	608
Derivative asset, fair value, gross liability	505	648
Derivatives Not Designated as Hedging Instruments [Member] | Physical Purchase Contracts [Member] | Inventories [Member]
Fair Values of Derivative Instruments
Derivative asset, fair value, gross asset	1	0
Derivative asset, fair value, gross liability	2	3
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	28	27
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	$ 10