Variable Interest Entities (Details) - Southern California Edison	3 Months Ended		12 Months Ended
	Mar. 31, 2016 USD ($) $ / shares MW	Mar. 31, 2015 USD ($) MW	Dec. 31, 2015 USD ($) $ / shares
Series K Preferred Stock
Unconsolidated Trust
Security dividend rate, (as a percent)	5.45%
Liquidation value (in dollars per share) | $ / shares	$ 2,500
Variable Interest Entity, Not Primary Beneficiary | SCE Power Purchase Contracts
Details of projects or entities
Power generating capacity (in megawatts) | MW	4,383	4,125
Payments to unconsolidated VIEs for power purchase contracts	$ 127,000,000	$ 103,000,000
Variable Interest Entity, Not Primary Beneficiary | SCE Trust I
Unconsolidated Trust
Common stock	10,000		$ 10,000
Dividend income	7,000,000	7,000,000
Dividend distributions	$ 7,000,000	7,000,000
Variable Interest Entity, Not Primary Beneficiary | SCE Trust I | Trust Securities [Member]
Unconsolidated Trust
Security dividend rate, (as a percent)	5.625%		5.625%
Liquidation preference	$ 475,000,000		$ 475,000,000
Liquidation value (in dollars per share) | $ / shares	$ 25		$ 25
Common stock	$ 10,000
Variable Interest Entity, Not Primary Beneficiary | SCE Trust I | Series F Preferred Stock
Unconsolidated Trust
Security dividend rate, (as a percent)	5.625%		5.625%
Liquidation preference	$ 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
Common stock	$ 10,000		$ 10,000
Dividend income	5,000,000	5,000,000
Dividend distributions	$ 5,000,000	5,000,000
Variable Interest Entity, Not Primary Beneficiary | SCE Trust II | Trust Securities [Member]
Unconsolidated Trust
Security dividend rate, (as a percent)	5.10%		5.10%
Liquidation preference	$ 400,000,000		$ 400,000,000
Liquidation value (in dollars per share) | $ / shares	$ 25		$ 25
Variable Interest Entity, Not Primary Beneficiary | SCE Trust II | Series G Preferred Stock
Unconsolidated Trust
Security dividend rate, (as a percent)	5.10%		5.10%
Liquidation preference	$ 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
Common stock	$ 10,000		$ 10,000
Dividend income	4,000,000	4,000,000
Dividend distributions	$ 4,000,000	$ 4,000,000
Variable Interest Entity, Not Primary Beneficiary | SCE Trust III | Trust Securities [Member]
Unconsolidated Trust
Security dividend rate, (as a percent)	5.75%		5.75%
Liquidation preference	$ 275,000,000		$ 275,000,000
Liquidation value (in dollars per share) | $ / shares	$ 25		$ 25
Variable Interest Entity, Not Primary Beneficiary | SCE Trust III | Series H Preferred Stock
Unconsolidated Trust
Security dividend rate, (as a percent)	5.75%		5.75%
Liquidation preference	$ 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
Common stock	$ 10,000		$ 10,000
Dividend income	4,000,000
Dividend distributions	$ 4,000,000
Variable Interest Entity, Not Primary Beneficiary | SCE Trust IV | Trust Securities [Member]
Unconsolidated Trust
Security dividend rate, (as a percent)	5.375%		5.375%
Liquidation preference	$ 325,000,000		$ 325,000,000
Liquidation value (in dollars per share) | $ / shares	$ 25		$ 25
Variable Interest Entity, Not Primary Beneficiary | SCE Trust IV | Series J Preferred Stock
Unconsolidated Trust
Security dividend rate, (as a percent)	5.375%		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 Trust V
Unconsolidated Trust
Common stock	$ 10,000
Dividend income	1,000,000
Dividend distributions	$ 1,000,000
Variable Interest Entity, Not Primary Beneficiary | SCE Trust V | Trust Securities [Member]
Unconsolidated Trust
Security dividend rate, (as a percent)	5.45%
Liquidation preference	$ 300,000,000
Liquidation value (in dollars per share) | $ / shares	$ 25
Common stock	$ 10,000
Variable Interest Entity, Not Primary Beneficiary | SCE Trust V | Series K Preferred Stock
Unconsolidated Trust
Security dividend rate, (as a percent)	5.45%
Liquidation preference	$ 300,000,000
Liquidation value (in dollars per share) | $ / shares	$ 2,500