Inventories - Schedule of Inventories (Details) - USD ($) $ in Millions	Jun. 30, 2021	Dec. 31, 2020
Inventory Disclosure [Abstract]
Crude oil and petroleum products	$ 4,365	$ 3,536
Materials and supplies	387	357
Inventories	$ 4,752	$ 3,893

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

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