Asset Acquisitions and Dispositions (Narrative - Assets Sold) (Details)		1 Months Ended							3 Months Ended				6 Months Ended	12 Months Ended
	May 27, 2020 USD ($) MBoe / D	Jan. 31, 2022 USD ($)	May 31, 2020 USD ($)	Mar. 31, 2020 USD ($)	Feb. 29, 2020 USD ($)	Sep. 30, 2019 USD ($)	Apr. 30, 2019 USD ($)	Jan. 31, 2019 USD ($)	Mar. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Jun. 30, 2019 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	May 10, 2021 USD ($)
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Equity in earnings of affiliates														$ 832,000,000	$ 432,000,000	$ 779,000,000
Gain on dispositions														486,000,000	549,000,000	1,966,000,000
Asia Pacific [Member] | Operating Segments [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Equity in earnings of affiliates														$ 343,000,000	137,000,000	461,000,000
Lower 48 Segment
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Proceeds from asset dispositions													$ 250,000,000
Before-tax gain (loss) on disposition													58,000,000
Basis for Amount														contingent payment, paid on an annual basis, is calculated monthly at $7 million per month in which the U.S. Henry Hub price is at or above $3.20 per MMBTU
Canada Segment [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Basis for Amount														contingent payment, calculated and paid on a quarterly basis, is $6 million CAD for every $1 CAD by which the WCS quarterly average crude price exceeds $52 CAD per barrel
Australia West Assets [Member] | Asia Pacific [Member] | Operating Segments [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Proceeds from asset dispositions			$ 765,000,000
Disposal Group, Including Discontinued Operation, Property, Plant, and Equipment, Net	$ 1,300,000,000
Asset Retirement Obligations Noncurrent	700,000,000
Total assets of discontinued operations	200,000,000
Disposition, Other current assets	100,000,000
Disposition, deferred tax liabilities	300,000,000
Disposition, Before-tax earnings															851,000,000	372,000,000
Gain (Loss) on Sale of Oil and Gas Property															587,000,000
Disposition, Cash	500,000,000
Disposition, other liabilities	$ 200,000,000
Barossa Project [Member] | Asia Pacific [Member] | Operating Segments [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Before-tax gain (loss) on disposition									$ 200,000,000
Production | MBoe / D	43
Receivable in dispute										$ 200,000,000					200,000,000		$ 200,000,000
Barossa Project [Member] | Asia Pacific [Member] | Operating Segments [Member] | Scenario Plan [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Proceeds from asset dispositions			$ 200,000,000
Waddell Ranch [Member] | Lower 48 Segment
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Proceeds from asset dispositions					$ 184,000,000
Gain on dispositions					$ 0
Niobrara [Member] | Lower 48 Segment
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Proceeds from asset dispositions				$ 359,000,000
Disposal Group, Including Discontinued Operation, Property, Plant, and Equipment, Net				433,000,000
Asset Retirement Obligations Noncurrent				34,000,000
Impairment Of Long Lived Assets To Be Disposed Of											$ 386,000,000
Total assets of discontinued operations				397,000,000
Gain (Loss) on Sale of Oil and Gas Property				$ 38,000,000
Niobrara [Member] | Lower 48 Segment | Operating Segments [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Results Of Operations Income Before Income Taxes										$ 372,000,000					25,000,000
Noncore Exploration Interests [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Before-tax gain (loss) on disposition													$ (179,000,000)
Noncore Exploration Interests [Member] | Lower 48 Segment | Subsequent Event [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Proceeds from asset dispositions		$ 440,000,000
Noncore Exploration Interests [Member] | Canada and Lower 48 [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Gain on dispositions														$ 369,000,000	$ 0
Golden Pass LNG Terminal and Golden Pass Pipeline [Member] | Lower 48 Segment | Operating Segments [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Equity interest of ConocoPhillips								12.40%
Equity in earnings of affiliates								$ (60,000,000)
UK Subsidiaries [Member] | Operating Segments [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
After-tax gain (loss) on disposition											2,100,000,000					2,100,000,000
UK Subsidiaries [Member] | Europe And North Africa Segment [Member] | Operating Segments [Member] | Scenario Plan [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Proceeds from asset dispositions						$ 2,200,000,000	$ 2,675,000,000
Disposal Group, Including Discontinued Operation, Property, Plant, and Equipment, Net						1,600,000,000
Asset Retirement Obligations Noncurrent						1,800,000,000
Total assets of discontinued operations						500,000,000
After-tax gain (loss) on disposition						2,100,000,000
Disposal Group, Including Discontinued Operation, Deferred Tax Assets						300,000,000
Working Capital and cash in net carrying value						100,000,000
Disposal Group Including Discontinued Operation Foreign Currency Translation Adjustment						500,000,000
Gain (Loss) on Sale of Oil and Gas Property						$ 1,700,000,000
Greater Sunrise Fields [Member] | Asia Pacific [Member] | Operating Segments [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Proceeds from asset dispositions												$ 350,000,000
After-tax gain (loss) on disposition												$ 52,000,000
Percent Sold												30.00%
Magnolia field and platform [Member] | Lower 48 Segment | Operating Segments [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Proceeds from asset dispositions											16,000,000
Disposal Group, Including Discontinued Operation, Property, Plant, and Equipment, Net											4,000,000					4,000,000
Gain (Loss) on Sale of Oil and Gas Property											82,000,000
Magnolia field and platform [Member] | Lower 48 Segment | Operating Segments [Member] | Asset Retirement Obligation Costs [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Liabilities of Disposal Group, Including Discontinued Operation, Noncurrent											$ 70,000,000					$ 70,000,000