Oil and Natural Gas Property Transactions - Narrative (Details) shares in Millions, $ in Millions				3 Months Ended								11 Months Ended	12 Months Ended
	Dec. 11, 2020 USD ($)	Nov. 22, 2020 USD ($) a well	Feb. 01, 2019 USD ($) shares	Dec. 31, 2020 USD ($) a well	Sep. 30, 2020 USD ($)	Jun. 30, 2020 USD ($)	Mar. 31, 2020 USD ($)	Dec. 31, 2019 USD ($) a well	Sep. 30, 2019 USD ($)	Jun. 30, 2019 USD ($)	Mar. 31, 2019 USD ($)	Dec. 31, 2019 USD ($) a well	Dec. 31, 2020 USD ($) a well $ / bbl $ / BTU	Dec. 31, 2019 USD ($) a day well $ / BTU	Dec. 31, 2018 USD ($)
Business Acquisition [Line Items]
Gains (losses) on sales of assets													$ 30	$ 43	$ (264)
Total revenues				$ 1,259	$ 975	$ 521	$ 2,541	$ 1,926	$ 2,087	$ 2,386	$ 2,196		5,296	8,595	10,030
Proceeds from divestitures of proved and unproved properties													$ 136	130	$ 2,231
Natural gas
Business Acquisition [Line Items]
Average sales price (in usd per unit) | $ / BTU													2.82
Mid-Continent
Business Acquisition [Line Items]
Proceeds from divestitures of proved and unproved properties														491
Gain (loss) on sale of oil and natural gas properties														$ 12
Area of land, net (in acres) | a								238,500				238,500		238,500
Productive gas wells, number of wells, net | well								3,200				3,200		3,200
Other properties
Business Acquisition [Line Items]
Proceeds from divestitures of proved and unproved properties														$ 37
Future natural gas prices 2023 | Natural gas
Business Acquisition [Line Items]
Average sales price (in usd per unit) | $ / BTU													3.00
Wildhorse resource development corporation
Business Acquisition [Line Items]
Common stock issued in the merger (in shares) | shares			3.6
Cash			$ 381											381
Total revenues												$ 752
Operating expenses												810
Other expenses												83
Energy related derivative | Oil
Business Acquisition [Line Items]
Average sales price (in usd per unit) | $ / bbl													56.33
Energy related derivative | Future NYMEX oil prices 2023 | Oil
Business Acquisition [Line Items]
Average sales price (in usd per unit) | $ / bbl													61.17
Haynesville Exchange
Business Acquisition [Line Items]
Number of producing wells with interest | well		144
Area of land with interest | a		50,000
Loss from exchange transaction		$ 128
Mid-Continent
Business Acquisition [Line Items]
Gains (losses) on sales of assets	$ 27
Disposal group, disposed of by sale, not discontinued operations
Business Acquisition [Line Items]
Proceeds from divestitures of proved and unproved properties													$ 130
Gain (loss) on sale of oil and natural gas properties													46
Disposal group, disposed of by sale, not discontinued operations | Mid-Continent
Business Acquisition [Line Items]
Consideration received	$ 130
Disposal group, disposed of by sale, not discontinued operations | Utica shale
Business Acquisition [Line Items]
Consideration received				$ 1,868									$ 1,868
Area of land, gross (in acres) | a				1,500,000									1,500,000
Area of land, net (in acres) | a				900,000									900,000
Productive gas wells, number of wells, net | well				920									920
Disposal group, disposed of by sale, not discontinued operations | Utica shale | Synthetic gas
Business Acquisition [Line Items]
Net rentable area (in acres) | a				320,000									320,000
Disposal group, disposed of by sale, not discontinued operations | Utica shale | Future natural gas prices
Business Acquisition [Line Items]
Consideration received								$ 100				100		$ 100
Period of trading days | day														20
Consecutive trading days | day														30
Disposal group, disposed of by sale, not discontinued operations | Utica shale | 2022 NYMEX natural gas | Future natural gas prices 2023
Business Acquisition [Line Items]
Average sales price (in usd per unit) | $ / BTU														3.25
Disposal group, disposed of by sale, not discontinued operations | Utica shale | 2022 NYMEX natural gas | Future natural gas prices
Business Acquisition [Line Items]
Consideration received								$ 50				$ 50		$ 50
Gain (loss) on sale of oil and natural gas properties													$ (273)
Disposal group, disposed of by sale, not discontinued operations | Utica shale | 2022 NYMEX natural gas | Future natural gas prices 2022
Business Acquisition [Line Items]
Average sales price (in usd per unit) | $ / BTU														3.00