Units Of Gasoline

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+ References

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+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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-Publisher FASB
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Financial Instruments (Narrative) (Detail) gal in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020 USD ($) gal	Sep. 30, 2019 USD ($)	Sep. 30, 2020 USD ($) gal	Sep. 30, 2019 USD ($)
Schedule of Cost-method Investments [Line Items] (Deprecated 2018-01-31)
Interest Rate Cash Flow Hedge Liability at Fair Value	$ 18		$ 18
Derivative Instruments, Gain (Loss) Recognized in Income, Net	51	$ (37)	61	$ (36)
Interest Rate Caps [Member]
Schedule of Cost-method Investments [Line Items] (Deprecated 2018-01-31)
Derivative, Notional Amount	8,552		8,552
Interest Rate Caps [Member] \| Subsidiaries [Member]
Schedule of Cost-method Investments [Line Items] (Deprecated 2018-01-31)
Derivative, Notional Amount	3,000		3,000
Interest Rate Swaps [Member]
Schedule of Cost-method Investments [Line Items] (Deprecated 2018-01-31)
Derivative, Notional Amount	1,950		1,950
Currency Swap [Member]
Schedule of Cost-method Investments [Line Items] (Deprecated 2018-01-31)
Derivative, Notional Amount	$ 1,309		$ 1,309
Commodity Contracts [Member]
Schedule of Cost-method Investments [Line Items] (Deprecated 2018-01-31)
Units Of Gasoline \| gal	5		5
Purchase [Member]
Schedule of Cost-method Investments [Line Items] (Deprecated 2018-01-31)
Derivative, Notional Amount	$ 2,800		$ 2,800
Sold [Member]
Schedule of Cost-method Investments [Line Items] (Deprecated 2018-01-31)
Derivative, Notional Amount	5,800		5,800
Not Designated As Hedging Instruments [Member] \| Commodity Contracts [Member]
Schedule of Cost-method Investments [Line Items] (Deprecated 2018-01-31)
Derivative Instruments, Gain (Loss) Recognized in Income, Net	(1)	1	6	(3)
Interest Expense [Member]
Schedule of Cost-method Investments [Line Items] (Deprecated 2018-01-31)
Derivative Instruments, Gain (Loss) Recognized in Income, Net	(10)	9	18	(20)
Operating Expense [Member]
Schedule of Cost-method Investments [Line Items] (Deprecated 2018-01-31)
Derivative Instruments, Gain (Loss) Recognized in Income, Net	$ 2	$ (1)	$ (4)	$ (1)