Inventory, Linefill and Base Gas and Long-term Inventory (Details) bbl in Thousands, Mcf in Thousands, $ in Millions	12 Months Ended
	Dec. 31, 2021 USD ($) $ / bbl $ / Mcf bbl Mcf	Dec. 31, 2020 USD ($) $ / bbl $ / Mcf bbl Mcf	Dec. 31, 2019 USD ($)	Jun. 30, 2021 USD ($)
Inventory-related disclosures
Charge related to the write-down of inventory	$ 0	$ 233	$ 11
Charge related to the write-down of inventory, long-term inventory		40
Inventory by category
Inventory	783	647
Linefill and base gas	907	982
Long-term inventory	253	130
Total	$ 1,943	$ 1,759
Crude oil
Inventory by category
Inventory, Volumes (in barrels or in Mcf) | bbl	8,041	13,450
Linefill and base gas, Volumes (in barrels or in Mcf) | bbl	15,199	14,669
Long-term inventory, Volumes (in barrels or in Mcf) | bbl	2,973	2,499
Inventory	$ 544	$ 441
Linefill and base gas	862	828
Long-term inventory	$ 209	$ 111
Inventory, Price/Unit of measure (in dollars per unit) | $ / bbl	67.65	32.79
Linefill and base gas, Price/Unit of measure (in dollars per unit) | $ / bbl	56.71	56.45
Long-term inventory, Price/Unit of measure (in dollars per unit) | $ / bbl	70.30	44.42
NGL
Inventory by category
Inventory, Volumes (in barrels or in Mcf) | bbl	6,982	12,302
Linefill and base gas, Volumes (in barrels or in Mcf) | bbl	1,633	1,640
Long-term inventory, Volumes (in barrels or in Mcf) | bbl	1,135	1,185
Inventory	$ 234	$ 199
Linefill and base gas	45	44
Long-term inventory	$ 44	$ 19
Inventory, Price/Unit of measure (in dollars per unit) | $ / bbl	33.51	16.18
Linefill and base gas, Price/Unit of measure (in dollars per unit) | $ / bbl	27.56	26.83
Long-term inventory, Price/Unit of measure (in dollars per unit) | $ / bbl	38.77	16.03
Natural gas
Inventory by category
Linefill and base gas, Volumes (in barrels or in Mcf) | Mcf	0	25,576
Linefill and base gas	$ 0	$ 110
Linefill and base gas, Price/Unit of measure (in dollars per unit) | $ / Mcf	0	4.30
Natural gas | Disposed of by sale | Pine Prairie and Southern Pines Natural Gas Storage Facilities
Inventory by category
Linefill and base gas				$ 110
Other
Inventory by category
Inventory	$ 5	$ 7