Description of Business, Basis of Presentation, and Significant Accounting Policies (Details) branded_wholesale_site in Thousands, gal / yr in Millions, bbl / d in Millions, $ in Millions		12 Months Ended
	Jan. 01, 2018 USD ($)	Dec. 31, 2018 USD ($) gal / yr bbl / d refinery ethanol_plant branded_wholesale_site	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Jan. 01, 2019 USD ($)
Basis of Presentation and Summary of Significant Accounting Policies (Textual)
Number of petroleum refineries owned | refinery		15
Combined total throughput capacity of petroleum refining (barrels per day) | bbl / d		3.1
Number of branded wholesale sites | branded_wholesale_site		7
Number of ethanol plants owned | ethanol_plant		14
Combined capacity of ethanol (gallons per year) | gal / yr		1,730
Operating expenses (excluding depreciation and amortization expense)		$ 4,690	$ 4,504	$ 4,251
General and administrative expenses (excluding depreciation and amortization expense)		925	829	709
Reclassification of stranded income tax effects of Tax Reform from accumulated other comprehensive loss to retained earnings		0
Derecognition of existing assets under construction related to build-to-suit lease arrangement		$ (42,473)	(40,010)
Minimum [Member]
Basis of Presentation and Summary of Significant Accounting Policies (Textual)
Property, plant, and equipment, useful life		25 years
Typical post-delivery payment terms (in days)		2 days
Maximum [Member]
Basis of Presentation and Summary of Significant Accounting Policies (Textual)
Property, plant, and equipment, useful life		30 years
Typical post-delivery payment terms (in days)		10 days
Accounting Standards Update 2017-07 [Member]
Basis of Presentation and Summary of Significant Accounting Policies (Textual)
Operating expenses (excluding depreciation and amortization expense)			42	44
General and administrative expenses (excluding depreciation and amortization expense)			$ (6)	$ (6)
Accounting Standards Update 2018-02 [Member]
Basis of Presentation and Summary of Significant Accounting Policies (Textual)
Reclassification of stranded income tax effects of Tax Reform from accumulated other comprehensive loss to retained earnings	$ 91
Topic 842 [Member] | Subsequent Event [Member]
Basis of Presentation and Summary of Significant Accounting Policies (Textual)
ROU assets for operating leases					$ 1,300
Lease liabilities for operating leases					1,300
Topic 842 [Member] | Subsequent Event [Member] | MVP Terminal [Member]
Basis of Presentation and Summary of Significant Accounting Policies (Textual)
Derecognition of existing assets under construction related to build-to-suit lease arrangement					$ 539