Variable Interest Entities (Details) (Southern California Edison, USD $)	3 Months Ended		1 Months Ended						3 Months Ended		1 Months Ended		1 Months Ended		3 Months Ended
	Mar. 31, 2013 SCE Trust I	Dec. 31, 2012 SCE Trust I	May 31, 2012 SCE Trust I Trust Securities	Mar. 31, 2013 SCE Trust I Trust Securities	Dec. 31, 2012 SCE Trust I Trust Securities	Mar. 31, 2013 SCE Trust I Series F	Dec. 31, 2012 SCE Trust I Series F	May 31, 2012 SCE Trust I Series F	Mar. 31, 2013 SCE Trust II	Jan. 31, 2013 SCE Trust II	Jan. 31, 2013 SCE Trust II Trust Securities	Mar. 31, 2013 SCE Trust II Trust Securities	Jan. 31, 2013 SCE Trust II Series G Preferred Stock	Mar. 31, 2013 SCE Trust II Series G Preferred Stock	Mar. 31, 2013 Variable Interest Entity, Not Primary Beneficiary SCE Power Purchase Contracts MW	Mar. 31, 2012 Variable Interest Entity, Not Primary Beneficiary SCE Power Purchase Contracts MW
Details of projects or entities
Power generating capacity for majority interest (in megawatts)															3,578	2,014
Payments to unconsolidated VIEs for power purchase contracts															$ 98,000,000	$ 78,000,000
Future power generating capacity for majority interest (in megawatts)															1,837
Unconsolidated Trust
Liquidation preference			475,000,000								400,000,000
Security dividend rate, (as a percent)			5.625%								5.10%		5.10%
Liquidation value (in dollars per share)			$ 25					$ 2,500			$ 25		$ 2,500
Common stock	10,000	10,000	10,000						10,000	10,000
Common stock, percentage issued to Southern California Edison			100.00%							100.00%
Preference stock				475,000,000	475,000,000	475,000,000	475,000,000	475,000,000				400,000,000	400,000,000	400,000,000
Dividend income and distributions	$ 7,000,000								$ 4,000,000