Segment Information (Details) $ in Millions	3 Months Ended						9 Months Ended
	Sep. 30, 2024 USD ($)	Jun. 30, 2024 USD ($)	Mar. 31, 2024 USD ($)	Sep. 30, 2023 USD ($)	Jun. 30, 2023 USD ($)	Mar. 31, 2023 USD ($)	Sep. 30, 2024 USD ($) segment	Sep. 30, 2023 USD ($)	Dec. 31, 2023 USD ($)
Segment Reporting [Abstract]
Number of reportable segments | segment							2
Number of operating segments | segment							2
Segment Reporting Information [Line Items]
Revenues from contracts with customers	$ 1,741			$ 1,771			$ 4,945	$ 4,822
Net gain (loss) on commodity derivatives	9			1			(14)	19
Income from equity method investments	39			38			104	140
Net gain on disposal of assets	0			1			10	6
Other income (expense)	2			2			4	19
Less costs and expenses:
Production	223			192			660	607
Shipping, handling and other operating, including related party	204			164			548	487
Exploration	9			20			30	46
Depreciation, depletion and amortization	627			583			1,728	1,662
Impairments	1			0			1	0
Taxes other than income	99			113			298	251
General and administrative	88			72			273	225
Net interest and other	77			94			226	268
Other net periodic benefit credits	(3)			(5)			(8)	(11)
Income tax provision (benefit)	179			127			360	314
Net income	287	$ 349	$ 297	453	$ 287	$ 417	933	1,157
Total assets	19,422			19,919			19,422	19,919	$ 19,575
Capital expenditures	458			449			1,726	1,673
Tax credit carryforward, valuation allowance	75						75
Marathon Oil Corp. | ConocoPhillips
Less costs and expenses:
Merger transaction costs	6						16
Eagle Ford
Less costs and expenses:
Taxes other than income								47
Permian Basin
Less costs and expenses:
Exploration				11				11
Dry well cost								10
U.S.
Segment Reporting Information [Line Items]
Revenues from contracts with customers	1,615			1,700			4,588	4,643
U.S. | Eagle Ford
Segment Reporting Information [Line Items]
Revenues from contracts with customers	707			717			1,920	1,967
Operating Segments | U.S.
Segment Reporting Information [Line Items]
Revenues from contracts with customers	1,615			1,700			4,588	4,643
Net gain (loss) on commodity derivatives	0			7			0	27
Income from equity method investments	0			0			0	0
Net gain on disposal of assets				0			0	0
Other income (expense)	(1)			0			(4)	12
Less costs and expenses:
Production	209			173			608	542
Shipping, handling and other operating, including related party	187			162			491	482
Exploration	9			8			26	19
Depreciation, depletion and amortization	611			570			1,673	1,622
Impairments	0						0
Taxes other than income	99			112			298	252
General and administrative	39			32			118	98
Net interest and other	0			0			0	0
Other net periodic benefit credits	0			0			0	0
Income tax provision (benefit)	98			145			295	372
Net income	362			505			1,075	1,295
Total assets	18,443			18,503			18,443	18,503
Capital expenditures	454			444			1,712	1,661
Operating Segments | Int’l
Segment Reporting Information [Line Items]
Revenues from contracts with customers	126			71			357	179
Net gain (loss) on commodity derivatives	0			0			0	0
Income from equity method investments	39			38			104	140
Net gain on disposal of assets				0			0	0
Other income (expense)	2			1			5	5
Less costs and expenses:
Production	14			19			52	65
Shipping, handling and other operating, including related party	17			2			47	5
Exploration	0			1			0	1
Depreciation, depletion and amortization	11			12			31	34
Impairments	0						0
Taxes other than income	0			0			0	0
General and administrative	3			3			10	9
Net interest and other	0			0			0	0
Other net periodic benefit credits	0			0			0	0
Income tax provision (benefit)	27			11			70	29
Net income	95			62			256	181
Total assets	882			1,072			882	1,072
Capital expenditures	3			1			7	3
Not Allocated to Segments
Segment Reporting Information [Line Items]
Revenues from contracts with customers	0			0			0	0
Net gain (loss) on commodity derivatives	9			(6)			(14)	(8)
Income from equity method investments	0			0			0	0
Net gain on disposal of assets				1			10	6
Other income (expense)	1			1			3	2
Less costs and expenses:
Production	0			0			0	0
Shipping, handling and other operating, including related party	0			0			10	0
Exploration	0			11			4	26
Depreciation, depletion and amortization	5			1			24	6
Impairments	1						1
Taxes other than income	0			1			0	(1)
General and administrative	46			37			145	118
Net interest and other	77			94			226	268
Other net periodic benefit credits	(3)			(5)			(8)	(11)
Income tax provision (benefit)	54			(29)			(5)	(87)
Net income	(170)			(114)			(398)	(319)
Total assets	97			344			97	344
Capital expenditures	$ 1			$ 4			$ 7	$ 9