Fair Value Measurements (Level 3 Fair Value Measurements) (Details) - SCE - Level 3 - Congestion revenue rights (GWh) - Auction prices $ in Millions	Mar. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)
Quantitative Information About Level 3 Measurements [Line Items]
Fair Value, Assets	$ 103	$ 120
Fair Value, Liabilities	$ 12	$ 12
CAISO CRR auction clearing prices \| Minimum
Quantitative Information About Level 3 Measurements [Line Items]
Derivative Asset (Liability) Net, Measurement Input	(3.84)	(9.67)
CAISO CRR auction clearing prices \| Maximum
Quantitative Information About Level 3 Measurements [Line Items]
Derivative Asset (Liability) Net, Measurement Input	300.47	300.47
CAISO CRR auction clearing prices \| Weighted Average
Quantitative Information About Level 3 Measurements [Line Items]
Derivative Asset (Liability) Net, Measurement Input	2.68	2.75

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
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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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-Paragraph 2
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+ References

No definition available.

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Fair value of financial and nonfinancial obligations.

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