Revenues and Segment Information, Components of Operating Income (Loss) (Details) $ in Millions		3 Months Ended
		Mar. 31, 2021 USD ($) segment	Mar. 31, 2020 USD ($)
Segment Information for our Reportable Segments
Revenues	[1]	$ 20,806	$ 22,102
Cost of sales:
Cost of materials and other		18,992	19,952
LCM inventory valuation adjustment		0	2,542
Operating expenses (excluding depreciation and amortization expense reflected below)		1,656	1,124
Depreciation and amortization expense		566	569
Total cost of sales		21,214	24,187
Other operating expenses		38	2
General and administrative expenses (excluding depreciation and amortization expense reflected below)		208	177
Depreciation and amortization expense		12	13
Operating loss		$ (666)	(2,277)
Disclosure of Entity's Reportable Segments (Textual)
Number of reportable segments | segment		3
Corporate, Reconciling Items And Eliminations [Member]
Segment Information for our Reportable Segments
Revenues		$ (142)	(119)
Cost of sales:
Operating loss		(221)	(191)
Corporate [Member]
Segment Information for our Reportable Segments
Revenues		0	0
Cost of sales:
General and administrative expenses (excluding depreciation and amortization expense reflected below)		208	177
Depreciation and amortization expense		12	13
Intersegment Eliminations [Member]
Segment Information for our Reportable Segments
Revenues		(142)	(119)
Cost of sales:
Cost of materials and other		(141)	(118)
LCM inventory valuation adjustment			0
Operating expenses (excluding depreciation and amortization expense reflected below)		0	0
Depreciation and amortization expense		0	0
Total cost of sales		(141)	(118)
Other operating expenses		0	0
Refining [Member]
Segment Information for our Reportable Segments
Revenues		19,469	20,985
Refining [Member] | Operating Segments [Member]
Segment Information for our Reportable Segments
Revenues		19,472	20,987
Cost of sales:
Cost of materials and other		18,022	19,127
LCM inventory valuation adjustment			2,414
Operating expenses (excluding depreciation and amortization expense reflected below)		1,471	995
Depreciation and amortization expense		533	536
Total cost of sales		20,026	23,072
Other operating expenses		38	2
General and administrative expenses (excluding depreciation and amortization expense reflected below)		0	0
Depreciation and amortization expense		0	0
Operating loss		(592)	(2,087)
Refining [Member] | Intersegment Eliminations [Member]
Segment Information for our Reportable Segments
Revenues		3	2
Renewable Diesel [Member]
Segment Information for our Reportable Segments
Revenues		352	306
Renewable Diesel [Member] | Operating Segments [Member]
Segment Information for our Reportable Segments
Revenues		431	359
Cost of sales:
Cost of materials and other		187	130
LCM inventory valuation adjustment			0
Operating expenses (excluding depreciation and amortization expense reflected below)		29	20
Depreciation and amortization expense		12	11
Total cost of sales		228	161
Other operating expenses		0	0
General and administrative expenses (excluding depreciation and amortization expense reflected below)		0	0
Depreciation and amortization expense		0	0
Operating loss		203	198
Renewable Diesel [Member] | Intersegment Eliminations [Member]
Segment Information for our Reportable Segments
Revenues		79	53
Ethanol [Member]
Segment Information for our Reportable Segments
Revenues		985	811
Ethanol [Member] | Operating Segments [Member]
Segment Information for our Reportable Segments
Revenues		1,045	875
Cost of sales:
Cost of materials and other		924	813
LCM inventory valuation adjustment			128
Operating expenses (excluding depreciation and amortization expense reflected below)		156	109
Depreciation and amortization expense		21	22
Total cost of sales		1,101	1,072
Other operating expenses		0	0
General and administrative expenses (excluding depreciation and amortization expense reflected below)		0	0
Depreciation and amortization expense		0	0
Operating loss		(56)	(197)
Ethanol [Member] | Intersegment Eliminations [Member]
Segment Information for our Reportable Segments
Revenues		$ 60	$ 64

[1] Includes excise taxes on sales by certain of our international operations of $1,120 million and $1,368 million for the three months ended March 31, 2021 and 2020, respectively.