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, 2014		Sep. 30, 2013		Sep. 30, 2014		Sep. 30, 2013		Sep. 30, 2014	Sep. 30, 2013
Southern California Edison | Level 3
Fair Value Disclosures Level 3 [Roll Forward]
Fair value of net liabilities at beginning of period	$ (878)		$ (967)		$ (805)		$ (791)		$ (758)	$ (1,031)
Total realized/unrealized gains (losses):
Included in regulatory assets and liabilities	120	[1]	(50)	[1]	43	[1]	(205)	[1]
Purchases	7		19		22		56
Settlements	(7)		(33)		(18)		(91)
Change during the period in unrealized losses related to assets and liabilities held at the end of the period	$ 71		$ (65)		$ (12)		$ (198)

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