Fair Value Measurements (Level 3 Rollforward) (Details) - Southern California Edison - Level 3 - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Fair Value Disclosures Level 3 [Roll Forward]
Fair value of net assets at beginning of period	$ 63	$ 52	$ 141	$ 101
Total realized/unrealized losses	0	(21)	(78)	(70)
Fair value of net assets (liabilities) at end of period	63	31	63	31
Change during the period in unrealized gains and losses related to assets and liabilities held at the end of the period	$ 30	$ 7	$ 27	$ 7

This element represents total gains or losses for the period (realized and unrealized), included in regulatory assets and liabilities measured at fair value on a recurring basis using unobservable inputs (level 3).

No definition available.

+ Details

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- Definition

This element represents the change during the period in unrealized gains (losses) for financial instruments, held at the end of the period, with unobservable inputs (level 3).

+ References

No definition available.

+ Details

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- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

+ References

No definition available.

+ Details

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- Definition

Fair value of financial instrument classified as derivative asset (liability) after deduction of derivative liability (asset), measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19279-110258

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