Acquisition and Divestitures (Narrative) (Details) $ in Millions					3 Months Ended				48 Months Ended
		Mar. 03, 2021 USD ($) MMBoe	Jan. 07, 2021 shares	Oct. 01, 2020 USD ($) $ / MMBTU $ / bbl	Mar. 31, 2021 USD ($) shares	Sep. 30, 2020 USD ($)	Mar. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2024	Dec. 31, 2020 USD ($)
Business Acquisition [Line Items]
Common Stock Shares Issued					$ 67					$ 38
Asset impairment charges	[1]						$ 179
BKV [Member] | Barnett Shale [Member]
Business Acquisition [Line Items]
Divestitures of property and equipment				$ 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
Contingent earnout payment period					The contingent payment period commenced on January 1, 2021 and has a term of four years.
Asset impairment charges						$ 3	$ 179	$ 748
BKV [Member] | Barnett Shale [Member] | Scenario Forecast [Member]
Business Acquisition [Line Items]
Contingent earnout payment period									The contingent payment period commenced on January 1, 2021 and has a term of four years.
Non Core Assets [Member]
Business Acquisition [Line Items]
Divestitures of property and equipment		$ 9
Gain on asset dispositions		35
Contingent earnout payments		$ 8
Total estimated proved reserves | MMBoe		3
Devon and WPX Agreement [Member]
Business Acquisition [Line Items]
Date of agreement			Jan. 07, 2021		Jan. 07, 2021
Per share conversion | shares			0.5165		0.5165
Common Stock Shares Issued					$ 5,400

[1] Devon recognized an $179 million asset impairment in the first quarter of 2020 related to the Barnett Shale assets primarily due to the difference between the net carrying value and the purchase price, net of estimated customary purchase price adjustments, which qualified as a level 2 fair value measurement.