Variable Interest Entities (Details) (Southern California Edison, Variable Interest Entity, Not Primary Beneficiary, USD $)	3 Months Ended
	Mar. 31, 2015 MW	Mar. 31, 2014 MW	Dec. 31, 2014
SCE Power Purchase Contracts
Details of projects or entities
Power generating capacity (in megawatts)	4,125	5,641
Payments to unconsolidated VIEs for power purchase contracts	$ 103,000,000	$ 125,000,000
SCE Trust I
Unconsolidated Trust
Dividend income	7,000,000	7,000,000
Dividend distributions	7,000,000	7,000,000
SCE Trust I | Trust Securities
Unconsolidated Trust
Security dividend rate, (as a percent)	5.625%
Liquidation preference	475,000,000		475,000,000
Liquidation value (in dollars per share)	$ 25
Common stock	10,000		10,000
SCE Trust I | Series F Preferred Stock
Unconsolidated Trust
Liquidation preference	475,000,000		475,000,000
Liquidation value (in dollars per share)	$ 2,500
SCE Trust II
Unconsolidated Trust
Dividend income	5,000,000	5,000,000
Dividend distributions	5,000,000	5,000,000
SCE Trust II | Trust Securities
Unconsolidated Trust
Security dividend rate, (as a percent)	5.10%
Liquidation preference	400,000,000		400,000,000
Liquidation value (in dollars per share)	$ 25
Common stock	10,000		10,000
SCE Trust II | Series G Preferred Stock
Unconsolidated Trust
Liquidation preference	400,000,000		400,000,000
Liquidation value (in dollars per share)	$ 2,500
SCE Trust III
Unconsolidated Trust
Dividend income	4,000,000	1,000,000
Dividend distributions	4,000,000	1,000,000
SCE Trust III | Trust Securities
Unconsolidated Trust
Security dividend rate, (as a percent)	5.75%
Liquidation preference	275,000,000
Liquidation value (in dollars per share)	$ 25
Common stock	10,000
SCE Trust III | Series H Preferred Stock
Unconsolidated Trust
Liquidation preference	$ 275,000,000
Liquidation value (in dollars per share)	$ 2,500