Fair Value Measurements (Quantitative Information About Level 3 Fair Value Measurements) (Details) - Southern California Edison - Level 3 - Congestion revenue rights - Auction prices $ in Millions	Sep. 30, 2020 USD ($)	Dec. 31, 2019 USD ($)
Quantitative Information About Level 3 Measurements [Line Items]
Fair Value, Assets	$ 30	$ 83
Fair Value, Liabilities	$ 2	$ 5
CAISO CRR auction prices \| Minimum
Quantitative Information About Level 3 Measurements [Line Items]
Fair value inputs, price level ($ per MWh)	(7.72)	3.59
CAISO CRR auction prices \| Maximum
Quantitative Information About Level 3 Measurements [Line Items]
Fair value inputs, price level ($ per MWh)	9.91	25.32
CAISO CRR auction prices \| Weighted Average [Member]
Quantitative Information About Level 3 Measurements [Line Items]
Fair value inputs, price level ($ per MWh)	1.72	1.97

Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
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Value of input used to measure net derivative asset (liability).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
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-Topic 820
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+ References

No definition available.

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Fair value of financial and nonfinancial obligations.

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