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Asset Acquisitions and Dispositions - Textual (Details) - Operating Segments [Member] $ in Millions	1 Months Ended			3 Months Ended
	Mar. 31, 2020 USD ($)	Feb. 29, 2020 USD ($)	Oct. 31, 2019 USD ($)	Mar. 31, 2020 USD ($) MBoe	Mar. 31, 2019 USD ($)
Lower 48 Segment
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Natural gas production \| MBoe				15
Australia West Assets [Member] \| Asia Pacific and Middle East [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Net carrying value	$ 700			$ 700
Amount of PP&E in carrying value of assets	1,300			1,300
Working Capital and cash in net carrying value	(400)			(400)
Amount of deferred taxes in carrying value of asset	(300)			(300)
Results Of Operations Income Before Income Taxes				192	$ 115
Australia West Assets [Member] \| Asia Pacific and Middle East [Member] \| Prepaid Expenses and Other Current Assets [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Amount of PP&E in carrying value of assets	1,300			1,300
Australia West Assets [Member] \| Asia Pacific and Middle East [Member] \| Scenario, Plan [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Proceeds from asset dispositions			$ 1,390
Australia West Assets [Member] \| Asia Pacific and Middle East [Member] \| Asset Retirement Obligation Costs [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Asset Retirement Obligation of held for sale or sold	700			700
Australia West Assets [Member] \| Asia Pacific and Middle East [Member] \| Asset Retirement Obligation Costs [Member] \| Other Accruals [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Asset Retirement Obligation of held for sale or sold	$ 700			$ 700
Barossa Project [Member] \| Asia Pacific and Middle East [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Ownership Percent	37.50%			37.50%
Barossa Project [Member] \| Asia Pacific and Middle East [Member] \| Scenario, Plan [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Proceeds from asset dispositions				$ 75
Darwin LNG Facility [Member] \| Asia Pacific and Middle East [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Ownership Percent	56.90%			56.90%
Bayu-Undan Field [Member] \| Asia Pacific and Middle East [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Ownership Percent	56.90%			56.90%
Poseidon Field [Member] \| Asia Pacific and Middle East [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Ownership Percent	40.00%			40.00%
Athena Field [Member] \| Asia Pacific and Middle East [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Ownership Percent	50.00%			50.00%
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
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
Net carrying value	397			$ 397
Amount of PP&E in carrying value of assets	433			433
Results Of Operations Income Before Income Taxes				27
Before-tax gain (loss) on disposition	(38)
Niobrara [Member] \| Lower 48 Segment \| Maximum [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Results Of Operations Income Before Income Taxes					$ (1)
Niobrara [Member] \| Lower 48 Segment \| Asset Retirement Obligation Costs [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Asset Retirement Obligation of held for sale or sold	$ 34			$ 34