Variable Interest Entities (Details) - Southern California Edison	3 Months Ended		9 Months Ended
	Sep. 30, 2015 USD ($) $ / shares MW	Sep. 30, 2014 USD ($) MW	Sep. 30, 2015 USD ($) $ / shares MW	Sep. 30, 2014 USD ($) MW	Dec. 31, 2014 USD ($)
Series J Preferred Stock
Unconsolidated Trust
Security dividend rate, (as a percent)	5.375%
Liquidation preference	$ 325,000,000		$ 325,000,000
Liquidation value (in dollars per share) | $ / shares	$ 2,500		$ 2,500
Variable Interest Entity, Not Primary Beneficiary | SCE Power Purchase Contracts
Details of projects or entities
Power generating capacity (in megawatts) | MW	4,062	5,341	4,062	5,341
Payments to unconsolidated VIEs for power purchase contracts	$ 270,000,000	$ 319,000,000	$ 451,000,000	$ 526,000,000
Variable Interest Entity, Not Primary Beneficiary | SCE Trust I
Unconsolidated Trust
Dividend income	7,000,000	7,000,000	20,000,000	20,000,000
Dividend distributions	7,000,000	7,000,000	$ 20,000,000	20,000,000
Variable Interest Entity, Not Primary Beneficiary | SCE Trust I | Trust Securities
Unconsolidated Trust
Security dividend rate, (as a percent)			5.625%
Liquidation preference	$ 475,000,000		$ 475,000,000		$ 475,000,000
Liquidation value (in dollars per share) | $ / shares	$ 25		$ 25
Common stock	$ 10,000		$ 10,000		10,000
Variable Interest Entity, Not Primary Beneficiary | SCE Trust I | Series F Preferred Stock
Unconsolidated Trust
Liquidation preference	$ 475,000,000		$ 475,000,000		475,000,000
Liquidation value (in dollars per share) | $ / shares	$ 2,500		$ 2,500
Variable Interest Entity, Not Primary Beneficiary | SCE Trust II
Unconsolidated Trust
Dividend income	$ 5,000,000	5,000,000	$ 15,000,000	15,000,000
Dividend distributions	5,000,000	5,000,000	$ 15,000,000	15,000,000
Variable Interest Entity, Not Primary Beneficiary | SCE Trust II | Trust Securities
Unconsolidated Trust
Security dividend rate, (as a percent)			5.10%
Liquidation preference	$ 400,000,000		$ 400,000,000		400,000,000
Liquidation value (in dollars per share) | $ / shares	$ 25		$ 25
Common stock	$ 10,000		$ 10,000		10,000
Variable Interest Entity, Not Primary Beneficiary | SCE Trust II | Series G Preferred Stock
Unconsolidated Trust
Liquidation preference	$ 400,000,000		$ 400,000,000		400,000,000
Liquidation value (in dollars per share) | $ / shares	$ 2,500		$ 2,500
Variable Interest Entity, Not Primary Beneficiary | SCE Trust III
Unconsolidated Trust
Dividend income	$ 4,000,000	4,000,000	$ 12,000,000	9,000,000
Dividend distributions	4,000,000	$ 4,000,000	$ 12,000,000	$ 9,000,000
Variable Interest Entity, Not Primary Beneficiary | SCE Trust III | Trust Securities
Unconsolidated Trust
Security dividend rate, (as a percent)			5.75%
Liquidation preference	$ 275,000,000		$ 275,000,000		275,000,000
Liquidation value (in dollars per share) | $ / shares	$ 25		$ 25
Common stock	$ 10,000		$ 10,000
Variable Interest Entity, Not Primary Beneficiary | SCE Trust III | Series H Preferred Stock
Unconsolidated Trust
Liquidation preference	$ 275,000,000		$ 275,000,000		$ 275,000,000
Liquidation value (in dollars per share) | $ / shares	$ 2,500		$ 2,500
Variable Interest Entity, Not Primary Beneficiary | SCE Trust IV
Unconsolidated Trust
Dividend income	$ 2,000,000		$ 2,000,000
Dividend distributions	2,000,000		$ 2,000,000
Variable Interest Entity, Not Primary Beneficiary | SCE Trust IV | Trust Securities
Unconsolidated Trust
Security dividend rate, (as a percent)			5.375%
Liquidation preference	$ 325,000,000		$ 325,000,000
Liquidation value (in dollars per share) | $ / shares	$ 25		$ 25
Common stock	$ 10,000		$ 10,000
Variable Interest Entity, Not Primary Beneficiary | SCE Trust IV | Series J Preferred Stock
Unconsolidated Trust
Liquidation preference	$ 325,000,000		$ 325,000,000