Acquisition and Divestitures (Narrative) (Details) $ in Millions		3 Months Ended
	Jan. 07, 2021	Mar. 31, 2022 USD ($) $ / bbl $ / MMBTU	Mar. 31, 2021 USD ($) MMBoe	Dec. 31, 2021 USD ($)
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations And Disposition [Line Items]
Common Stock Shares Issued		$ 66		$ 66
Gain loss on disposition of assets		1	$ 32
Barnett Shale [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations And Disposition [Line Items]
Contingent earnout payments		$ 65
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.
Barnett Shale [Member] | Other Current Assets [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations And Disposition [Line Items]
Contingent earnout payments		$ 51
Barnett Shale [Member] | Other Noncurrent Assets [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations And Disposition [Line Items]
Contingent earnout payments		60
Non Core Assets [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations And Disposition [Line Items]
Divestitures of property and equipment			9
Gain on asset dispositions			$ 35
Contingent earnout payments		4
Change in contingent earnout payments		$ 4
Total estimated proved reserves | MMBoe			3
Devon and WPX Agreement [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations And Disposition [Line Items]
Date of agreement	Jan. 07, 2021	Jan. 07, 2021
Conversion of common stock into right to recieve per share	0.5165
Common Stock Shares Issued		$ 5,400