Inventories (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020	Mar. 31, 2020
Schedule of Inventories
Refinery feedstocks	$ 2,272		$ 2,272		$ 1,979
Refined petroleum products and blendstocks	3,173		3,173		3,425
Renewable diesel feedstocks and products	28		28		50
Ethanol feedstocks and products	338		338		297
Materials and supplies	292		292		287
Inventories	6,103		6,103		6,038
Inventories (Textual)
LCM inventory valuation reserve		$ 294		$ 294		$ 2,500
Lower of cost or market (LCM) inventory valuation adjustment	0	$ (2,248)	0	$ 294
Excess of market value over carrying amount of LIFO inventories	4,100		4,100		1,300
Amount of non-LIFO inventory	$ 1,000		$ 1,000		$ 918

The aggregate carrying amount as of the balance sheet date of unrefined petroleum and the liquid hydrocarbon components recovered from natural gas.

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The excess of replacement or current cost over the stated LIFO (last in first out) inventory value when the LIFO inventory method is utilized.

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Carrying amount as of the balance sheet date of finished goods inventories for petroleum products, crude oil, petrochemical products, and other oil and gas inventories.

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Amount after valuation and LIFO reserves of inventory expected to be sold, or consumed within one year or operating cycle, if longer.

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Gross amount of unprocessed materials to be used in manufacturing or production process and supplies that will be consumed.

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Amount of valuation reserve for inventory.

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Amount of loss from reductions in inventory due to subsequent measurement adjustments, including, but not limited to, physical deterioration, obsolescence, or changes in price levels.

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The amount of weighted average cost inventory present at the reporting date when inventory is valued using different valuation methods.

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Carrying amount as of the balance sheet date of ethanol feedstocks and products.

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Inventories, Textual [Abstract]

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Carrying amount as of the balance sheet date of renewable diesel feedstocks and products.

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