Revenues and Segment Information, Components of Operating Income (Details) $ in Millions		3 Months Ended
		Mar. 31, 2019 USD ($) refinery ethanol_plant segment	Mar. 31, 2018 USD ($)
Segment Information for our Reportable Segments
Revenues	[1]	$ 24,263	$ 26,439
Cost of materials and other		21,978	23,756
Operating expenses (excluding depreciation and amortization expense reflected below)		1,215	1,136
Depreciation and amortization expense		537	485
Total cost of sales		23,730	25,377
Other operating expenses		2	10
General and administrative expenses (excluding depreciation and amortization expense reflected below)		209	238
Depreciation and amortization expense		14	13
Operating income (loss)		$ 308	801
Disclosure of Entity's Reportable Segments (Textual)
Number of reportable segments | segment		3
Number of petroleum refineries | refinery		15
Number of ethanol plants | ethanol_plant		14
Corporate, Reconciling Items And Eliminations [Member]
Segment Information for our Reportable Segments
Revenues		$ (105)	(91)
Operating income (loss)		(223)	(250)
Corporate [Member]
Segment Information for our Reportable Segments
Revenues		0	1
General and administrative expenses (excluding depreciation and amortization expense reflected below)		209	238
Depreciation and amortization expense		14	13
Intersegment Eliminations [Member]
Segment Information for our Reportable Segments
Revenues		(105)	(92)
Cost of materials and other		(105)	(92)
Operating expenses (excluding depreciation and amortization expense reflected below)		0	0
Depreciation and amortization expense		0	0
Total cost of sales		(105)	(92)
Other operating expenses		0	0
Refining [Member]
Segment Information for our Reportable Segments
Revenues		23,218	25,453
Refining [Member] | Operating Segments [Member]
Segment Information for our Reportable Segments
Revenues		23,220	25,457
Cost of materials and other		21,165	23,164
Operating expenses (excluding depreciation and amortization expense reflected below)		1,071	1,011
Depreciation and amortization expense		503	461
Total cost of sales		22,739	24,636
Other operating expenses		2	10
General and administrative expenses (excluding depreciation and amortization expense reflected below)		0	0
Depreciation and amortization expense		0	0
Operating income (loss)		479	811
Refining [Member] | Intersegment Eliminations [Member]
Segment Information for our Reportable Segments
Revenues		2	4
Ethanol [Member]
Segment Information for our Reportable Segments
Revenues		793	877
Ethanol [Member] | Operating Segments [Member]
Segment Information for our Reportable Segments
Revenues		845	923
Cost of materials and other		694	749
Operating expenses (excluding depreciation and amortization expense reflected below)		125	111
Depreciation and amortization expense		23	18
Total cost of sales		842	878
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 income (loss)		3	45
Ethanol [Member] | Intersegment Eliminations [Member]
Segment Information for our Reportable Segments
Revenues		52	46
Renewable Diesel [Member]
Segment Information for our Reportable Segments
Revenues		252	108
Renewable Diesel [Member] | Operating Segments [Member]
Segment Information for our Reportable Segments
Revenues		303	150
Cost of materials and other		224	(65)
Operating expenses (excluding depreciation and amortization expense reflected below)		19	14
Depreciation and amortization expense		11	6
Total cost of sales		254	(45)
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 income (loss)		49	195
Renewable Diesel [Member] | Intersegment Eliminations [Member]
Segment Information for our Reportable Segments
Revenues		$ 51	$ 42

[1] Includes excise taxes on sales by certain of our international operations of $1,330 million and $1,464 million for the three months ended March 31, 2019 and 2018, respectively.