Derivatives (Effect of Commodity Derivative Instruments in Statements of Income) (Detail) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2026	Sep. 30, 2025	Sep. 30, 2026	Sep. 30, 2025
Derivative [Line Items]
Unrealized Gain (Loss) on Derivatives			$ (1,846)	$ 45
Commodity derivatives
Derivative [Line Items]
Gain (Loss)	$ (499)	$ (4)	(1,083)	(37)
Commodity derivatives \| Income Statement Location [Axis]: us-gaap:CostOfGoodsAndServicesSold
Derivative [Line Items]
Gain (Loss)	(470)	(6)	(997)	(42)
Realized Gain (Loss), Investment and Derivative, Operating, before Tax	32	(19)	(904)	(68)
Unrealized Gain (Loss) on Derivatives	(502)	13	(93)	26
Commodity derivatives \| Income Statement Location [Axis]: us-gaap:OtherOperatingIncome
Derivative [Line Items]
Gain (Loss)	0	2	(12)	5
Realized Gain (Loss), Investment and Derivative, Operating, before Tax	(8)	6	(9)	9
Unrealized Gain (Loss) on Derivatives	8	(4)	(3)	(4)
Commodity derivatives \| Income Statement Location [Axis]: us-gaap:RevenueFromContractWithCustomerExcludingAssessedTax
Derivative [Line Items]
Gain (Loss)	(29)	0	(74)	0
Realized Gain (Loss), Investment and Derivative, Operating, before Tax	(13)	0	(53)	0
Unrealized Gain (Loss) on Derivatives	$ (16)	$ 0	$ (21)	$ 0

Derivative Instruments Not Designated as Hedging Instruments, Realized Gain (Loss), NetRealized Gain

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- Definition

Amount of increase (decrease) in the fair value of derivatives recognized in the income statement.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 815
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 4A
-Subparagraph (b)(1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480434/815-10-50-4A

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Topic 825
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 10
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482881/825-10-55-10

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 815
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 5A
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480434/815-10-50-5A

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 18
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481112/505-10-50-18

Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 815
-SubTopic 20
-Name Accounting Standards Codification
-Section 25
-Paragraph 6A
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480682/815-20-25-6A

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- Definition

The net change in the difference between the fair value and the carrying value, or in the comparative fair values, of open derivatives, commodity, or energy contracts, held at each balance sheet date, that was included in earnings for the period.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section 45
-Paragraph 28
-Subparagraph (b)
-SubTopic 10
-Topic 230
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482740/230-10-45-28

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