Fair Value Measurements (Level 3 Rollforward) (Details) (Southern California Edison, Level 3, USD $) In Millions, unless otherwise specified	3 Months Ended				9 Months Ended
	Sep. 30, 2013		Sep. 30, 2012		Sep. 30, 2013		Sep. 30, 2012
Southern California Edison | Level 3
Fair Value Disclosures Level 3 [Roll Forward]
Fair value of net asset (liabilities) at beginning of period	$ (967)		$ (739)		$ (791)		$ (754)
Total realized/unrealized gains (losses):
Included in regulatory assets and liabilities	(50)	[1]	(180)	[1]	(205)	[1]	(203)	[1]
Purchases	19		33		56		84
Settlements	(33)		(44)		(91)		(57)
Fair value of net liabilities at end of period	(1,031)		(930)		(1,031)		(930)
Change during the period in unrealized losses related to assets and liabilities held at the end of the period	$ (65)		$ (222)		$ (198)		$ (244)

[1] Due to regulatory mechanisms, SCE's realized and unrealized gains and losses are recorded as regulatory assets and liabilities.