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Inventories - Summary Of Inventories (Detail) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Inventory Disclosure [Abstract]
Crude oil and refinery feedstocks	$ 3,415	$ 3,655
Refined products	5,152	5,234
Materials and supplies	907	720
Merchandise	222	228
Total	$ 9,696	$ 9,837

X

- Definition

Balance includes refined products. Inventories are carried at the lower of cost or market value. The cost of inventories of refined products is determined primarily under the last-in, first-out ("LIFO") method.

+ References

No definition available.

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- Definition

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

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.6(a))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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- Definition

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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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section 45
-Paragraph 1
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-Name Accounting Standards Codification
-Topic 330
-SubTopic 10
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- Definition

Amount before valuation and LIFO reserves of other supplies used within the manufacturing or production process expected to be consumed within one year or operating cycle, if longer.

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-Publisher FASB
-Name Accounting Standards Codification
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Carrying amount as of the balance sheet date of merchandise inventory purchased by a retailer, wholesaler or distributor and held for future sale.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.6(a))
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