Derivative Instruments (Balance Sheet Disclosures) (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2015		Dec. 31, 2014
Fair Value of Derivative Instruments
Short-Term, Derivative Assets	$ 94		$ 102
Long-Term, Derivative Assets	212		219
Short-Term, Derivative Liabilities	185		196
Long-Term, Derivative Liabilities	1,107		1,052
Southern California Edison
Fair Value of Derivative Instruments
Short-Term, Derivative Assets	94		102
Long-Term, Derivative Assets	212		219
Short-Term, Derivative Liabilities	185		196
Long-Term, Derivative Liabilities	1,107		1,052
Southern California Edison | Electric Utility | Economic hedges
Derivatives
Collateral already posted	10		13
Southern California Edison | Commodity Contracts | Electric Utility
Fair Value of Derivative Instruments
Short-Term, Derivative Assets	94		102
Long-Term, Derivative Assets	212		219
Derivative Assets, Total	306		321
Short-Term, Derivative Liabilities	185		196
Long-Term, Derivative Liabilities	1,107		1,052
Derivative Liabilities, Total	1,292		1,248
Net Liability	986		927
Southern California Edison | Commodity Contracts | Electric Utility | Economic hedges
Fair Value of Derivative Instruments
Short-Term, Derivative Assets	97		104
Long-Term, Derivative Assets	212		219
Derivative Assets, Total	309		323
Short-Term, Derivative Liabilities	259		259
Long-Term, Derivative Liabilities	1,107		1,052
Derivative Liabilities, Total	1,366		1,311
Net Liability	1,057		988
Southern California Edison | Commodity Contracts | Electric Utility | Netting and Collateral
Fair Value of Derivative Instruments
Short-Term, Derivative Assets	(3)		(2)
Long-Term, Derivative Assets	0		0
Derivative Assets, Total	(3)		(2)
Short-Term, Derivative Liabilities	(3)		(2)
Long-Term, Derivative Liabilities	0		0
Derivative Liabilities, Total	(3)		(2)
Net Liability	0		0
Southern California Edison | Commodity Contracts | Electric Utility | Cash Collateral Posted
Fair Value of Derivative Instruments
Short-Term, Derivative Assets	0	[1]	0	[1]
Long-Term, Derivative Assets	0	[1]	0	[1]
Derivative Assets, Total	0	[1]	0	[1]
Short-Term, Derivative Liabilities	(71)	[1]	(61)	[1]
Long-Term, Derivative Liabilities	0	[1]	0	[1]
Derivative Liabilities, Total	(71)	[1]	(61)	[1]
Net Liability	(71)	[1]	(61)	[1]
Other Current Assets | Southern California Edison | Commodity Contracts
Derivatives
Collateral already posted	$ 36		$ 36

[1] In addition, at both March 31, 2015 and December 31, 2014, SCE had posted $36 million of collateral that is not offset against derivative liabilities and is reflected in "Other current assets" on the consolidated balance sheets.