Fair Value Measurements (Level 3 Rollforward) (Details) (Southern California Edison, Level 3, USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2015		Mar. 31, 2014
Southern California Edison | Level 3
Fair Value Disclosures Level 3 [Roll Forward]
Fair value of net liabilities at beginning of period	$ (902)		$ (805)
Total realized/unrealized gains (losses):
Included in regulatory assets and liabilities	(74)	[1]	31	[1]
Purchases	0		7
Settlements	0		(6)
Fair value of net liabilities at end of period	(976)		(773)
Change during the period in unrealized losses related to assets and liabilities held at the end of the period	$ (96)		$ 22

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