Discontinued Operations (Narrative) (Details) $ in Millions, $ in Billions				3 Months Ended					5 Months Ended	6 Months Ended	12 Months Ended			48 Months Ended
		Oct. 01, 2020 USD ($) $ / MMBTU $ / bbl	Dec. 17, 2019	Dec. 31, 2019 USD ($)	Sep. 30, 2019 USD ($)	Jun. 30, 2019 USD ($)	Jun. 30, 2019 CAD ($)	Sep. 30, 2018 USD ($)	Dec. 31, 2018 USD ($)	Jun. 30, 2020 USD ($)	Dec. 31, 2020 USD ($) MMcf	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2024 USD ($)	Apr. 30, 2020 USD ($)
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Asset impairments											$ 182	$ 785
Goodwill				$ 88								88
Restricted cash				380					$ 32		190	380	$ 32
Gain recognized on sale of business, pre-tax											$ (1)	222	2,593
Foreign currency translation adjustment	[1]											1,237
Charge on early retirement of debt, cash retirement costs													304
Settlement of long-term obligations duration											13 years
Canadian Divestiture [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Estimated cash abandonment charges per quarter											$ 8
Senior Notes [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Charge on early retirement of debt, cash retirement costs													304
Loss on early retirement of debt, noncash charges													8
EnLink and General Partner [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Proceeds from the sale of business								$ 3,125					3,125
Gain recognized on sale of business, pre-tax								2,600					2,600
Gain recognized on sale of business, after-tax								$ 2,200					$ 2,200
Effective close date of divestiture													Jul. 18, 2018
Cash income taxes													$ 12
Net cash outflows									$ 380		$ 430	560
EnLink and General Partner [Member] | Chisholm Gathering and Processing Contract [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Gathering and processing minimum volume commitments period end											expired at the end of 2020
EnLink and General Partner [Member] | Bridgeport and Cana Gathering and Processing Contracts [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Commitment Termination Date											Dec. 31, 2029
EnLink and General Partner [Member] | Maximum [Member] | Chisholm Gathering and Processing Contract [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Minimum gathering volume commitment | MMcf											128
Minimum processing volume commitment | MMcf											128
EnLink and General Partner [Member] | Minimum [Member] | Chisholm Gathering and Processing Contract [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Minimum gathering volume commitment | MMcf											77
Minimum processing volume commitment | MMcf											77
Barnett Shale [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Asset impairments				748							$ 182	748
Goodwill				$ 88								$ 88
Proceeds from the sale of business		$ 490
Contingent earnout payments		$ 260
Henry Hub gas price for contingent earnout payment upside | $ / MMBTU		2.75
WTI oil price for contingent earnout payment upside | $ / bbl		50
Cash deposit received															$ 170
Contingent payments valuation											66
Restricted cash											20
Estimated cash abandonment charges per quarter											$ 2
Barnett Shale [Member] | Scenario Forecast [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Contingent earnout payment period														The contingent payment period commences on January 1, 2021 and has a term of four years.
Barnett Shale [Member] | BKV [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Percentage of estimated U.S. total proved reserves associated with divestiture assets			45.00%
Proceeds from the sale of business		$ 490
Henry Hub gas price for contingent earnout payment upside | $ / MMBTU		2.75
WTI oil price for contingent earnout payment upside | $ / bbl		50
Cash deposit received															$ 170
Contingent earnout payment period											The contingent payment period commences on January 1, 2021 and has a term of four years.
Barnett Shale [Member] | BKV [Member] | Scenario Forecast [Member] | Maximum [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Contingent earnout payments														$ 260
Canadian Business Segment [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Restricted cash											$ 170
Proceeds from the sale of business						$ 2,600	$ 3.4
Gain recognized on sale of business, pre-tax						223
Gain recognized on sale of business, after-tax						425
Income taxes paid										$ 175
Foreign currency translation adjustment						$ 1,200
Charge on early retirement of debt, cash retirement costs					$ 52
Loss on early retirement of debt, noncash charges					6
Effective close date of divestiture												Jun. 27, 2019
Canadian Business Segment [Member] | 4.00% due July 15, 2021 [Member] | Senior Notes [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Long-term debt retired					$ 500
Debt interest rate, stated percentage					4.00%
Debt, maturity date					Jul. 15, 2021
Canadian Business Segment [Member] | 3.25% due May 15, 2022 [Member] | Senior Notes [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Long-term debt retired					$ 1,000
Debt interest rate, stated percentage					3.25%
Debt, maturity date					May 15, 2022

[1] In conjunction with the sale of substantially all of its oil and gas assets and operations in Canada, Devon released the cumulative translation adjustment as part of its gain on the disposition of its Canadian business. See Note 19 for additional details.