Segment Information - Schedule of Segment Reporting Information (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Segment Reporting Information [Line Items]
Sales and other revenues:		$ 7,251	$ 7,207	$ 20,405	$ 22,080
Cost of sales:
Cost of materials and other	[1]	5,692	6,158	16,608	18,835
Lower of cost or market inventory valuation adjustments		66	202	97	(20)
Operating expenses		590	630	1,758	1,828
Total cost of sales	[2]	6,348	6,990	18,463	20,643
Selling, general and administrative expenses	[2]	105	118	323	327
Depreciation and amortization		230	210	681	613
Asset impairments			10	1	10
Other operating expenses, net		4	10	18	10
Income (loss) from operations		564	(121)	920	487
Earnings of equity method investments		6	8	27	24
Interest income		11	18	27	59
Interest expense		(51)	(40)	(153)	(127)
Other income (expense), net		(2)	4	(48)	5
Income (loss) before income taxes		528	(131)	773	448
Capital expenditures		121	124	318	297
Corporate, Other and Eliminations
Segment Reporting Information [Line Items]
Sales and other revenues:		(1,182)	(1,240)	(3,254)	(3,477)
Intersegment Eliminations
Segment Reporting Information [Line Items]
Sales and other revenues:		(1,182)	(1,240)	(3,254)	(3,477)
Corporate, Non-Segment
Segment Reporting Information [Line Items]
Sales and other revenues:		0	0	0	0
Cost of sales:
Cost of materials and other		(1,183)	(1,238)	(3,256)	(3,474)
Lower of cost or market inventory valuation adjustments		0	0	0	0
Operating expenses		0	0	3	0
Total cost of sales		(1,183)	(1,238)	(3,253)	(3,474)
Selling, general and administrative expenses		4	10	16	22
Depreciation and amortization		18	20	54	51
Asset impairments			0		0
Other operating expenses, net		0		0
Income (loss) from operations		(21)	(32)	(71)	(76)
Earnings of equity method investments		0	1	0	2
Interest income		8	11	16	43
Interest expense		(49)	(30)	(143)	(95)
Other income (expense), net		(4)	7	(11)	6
Income (loss) before income taxes		(66)	(43)	(209)	(120)
Capital expenditures		8	12	16	37
Refining
Segment Reporting Information [Line Items]
Sales and other revenues:		5,507	5,387	15,588	16,730
Cost of sales:
Other operating expenses, net		4		18
Refining | Operating Segments
Segment Reporting Information [Line Items]
Sales and other revenues:		6,443	6,382	18,113	19,564
Cost of sales:
Cost of materials and other		5,278	5,732	15,463	17,497
Lower of cost or market inventory valuation adjustments		46	199	102	(22)
Operating expenses		447	485	1,349	1,407
Total cost of sales		5,771	6,416	16,914	18,882
Selling, general and administrative expenses		53	55	159	154
Depreciation and amortization		139	123	410	363
Asset impairments			0		0
Income (loss) from operations		476	(212)	612	165
Earnings of equity method investments		0	0	0	0
Interest income		0	0	0	0
Interest expense		0	0	0	0
Other income (expense), net		0	0	0	0
Income (loss) before income taxes		476	(212)	612	165
Capital expenditures		79	71	209	162
Refining | Intersegment Eliminations
Segment Reporting Information [Line Items]
Sales and other revenues:		(936)	(995)	(2,525)	(2,834)
Renewables
Segment Reporting Information [Line Items]
Sales and other revenues:		163	160	388	520
Renewables | Operating Segments
Segment Reporting Information [Line Items]
Sales and other revenues:		277	265	725	753
Cost of sales:
Cost of materials and other		267	237	688	688
Lower of cost or market inventory valuation adjustments		20	3	(5)	2
Operating expenses		22	25	67	76
Total cost of sales		309	265	750	766
Selling, general and administrative expenses		1	2	2	4
Depreciation and amortization		22	21	71	61
Asset impairments			0		0
Other operating expenses, net		0		0
Income (loss) from operations		(55)	(23)	(98)	(78)
Earnings of equity method investments		0	0	0	0
Interest income		0	1	1	1
Interest expense		(1)	(2)	(5)	(5)
Other income (expense), net		0	0	0	0
Income (loss) before income taxes		(56)	(24)	(102)	(82)
Capital expenditures		0	1	2	7
Renewables | Intersegment Eliminations
Segment Reporting Information [Line Items]
Sales and other revenues:		(114)	(105)	(337)	(233)
Marketing
Segment Reporting Information [Line Items]
Sales and other revenues:		898	950	2,410	2,668
Marketing | Operating Segments
Segment Reporting Information [Line Items]
Sales and other revenues:		898	950	2,410	2,668
Cost of sales:
Cost of materials and other		860	918	2,304	2,591
Lower of cost or market inventory valuation adjustments		0	0	0	0
Operating expenses		0	0	0	0
Total cost of sales		860	918	2,304	2,591
Selling, general and administrative expenses		10	10	26	24
Depreciation and amortization		7	6	21	19
Asset impairments			0		0
Other operating expenses, net		0		0
Income (loss) from operations		21	16	59	34
Earnings of equity method investments		0	0	0	0
Interest income		0	0	0	0
Interest expense		0	0	0	0
Other income (expense), net		1	0	1	0
Income (loss) before income taxes		22	16	60	34
Capital expenditures		17	13	33	33
Marketing | Intersegment Eliminations
Segment Reporting Information [Line Items]
Sales and other revenues:		0	0	0	0
Lubricants & Specialties
Segment Reporting Information [Line Items]
Sales and other revenues:		654	683	1,932	2,084
Lubricants & Specialties | Operating Segments
Segment Reporting Information [Line Items]
Sales and other revenues:		655	686	1,938	2,095
Cost of sales:
Cost of materials and other		470	509	1,409	1,533
Lower of cost or market inventory valuation adjustments		0	0	0	0
Operating expenses		71	61	198	189
Total cost of sales		541	570	1,607	1,722
Selling, general and administrative expenses		36	38	115	112
Depreciation and amortization		26	22	70	67
Asset impairments			0		0
Other operating expenses, net		0		0
Income (loss) from operations		52	56	146	194
Earnings of equity method investments		0	0	0	0
Interest income		2	3	4	6
Interest expense		0	0	0	(1)
Other income (expense), net		0	(2)	2	(1)
Income (loss) before income taxes		54	57	152	198
Capital expenditures		8	11	28	23
Lubricants & Specialties | Intersegment Eliminations
Segment Reporting Information [Line Items]
Sales and other revenues:		(1)	(3)	(6)	(11)
Midstream
Segment Reporting Information [Line Items]
Sales and other revenues:		29	27	87	78
Midstream | Operating Segments
Segment Reporting Information [Line Items]
Sales and other revenues:		160	164	473	477
Cost of sales:
Cost of materials and other		0	0	0	0
Lower of cost or market inventory valuation adjustments		0	0	0	0
Operating expenses		50	59	141	156
Total cost of sales		50	59	141	156
Selling, general and administrative expenses		1	3	5	11
Depreciation and amortization		18	18	55	52
Asset impairments			10		10
Other operating expenses, net		0		0
Income (loss) from operations		91	74	272	248
Earnings of equity method investments		6	7	27	22
Interest income		1	3	6	9
Interest expense		(1)	(8)	(5)	(26)
Other income (expense), net		1	(1)	(40)	0
Income (loss) before income taxes		98	75	260	253
Capital expenditures		9	16	30	35
Midstream | Intersegment Eliminations
Segment Reporting Information [Line Items]
Sales and other revenues:		$ (131)	$ (137)	$ (386)	$ (399)

[1] Exclusive of Lower of cost or market inventory valuation adjustments.

[2] Exclusive of Depreciation and amortization.