Derivative Instruments (Balance Sheet Disclosures) (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2013		Dec. 31, 2012
Fair Value of Derivative Instruments
Short-Term, Derivative Assets	$ 47		$ 129
Long-Term, Derivative Assets	207		85
Short-Term, Derivative Liabilities	174		126
Long-Term, Derivative Liabilities	1,137		939
Southern California Edison
Fair Value of Derivative Instruments
Short-Term, Derivative Assets	47		129
Long-Term, Derivative Assets	207		85
Short-Term, Derivative Liabilities	174		126
Long-Term, Derivative Liabilities	1,137		939
Southern California Edison | Commodity Contracts | Electric Utility
Fair Value of Derivative Instruments
Short-Term, Derivative Assets	47		129
Long-Term, Derivative Assets	207		85
Derivative Assets, Total	254		214
Short-Term, Derivative Liabilities	174		126
Long-Term, Derivative Liabilities	1,137		939
Derivative Liabilities, Total	1,311		1,065
Net Liability	1,057		851
Southern California Edison | Commodity Contracts | Electric Utility | Economic hedges
Fair Value of Derivative Instruments
Short-Term, Derivative Assets	53		151
Long-Term, Derivative Assets	207		91
Derivative Assets, Total	260		242
Short-Term, Derivative Liabilities	195		186
Long-Term, Derivative Liabilities	1,143		954
Derivative Liabilities, Total	1,338		1,140
Net Liability	1,078		898
Southern California Edison | Commodity Contracts | Electric Utility | Netting and Collateral
Fair Value of Derivative Instruments
Short-Term, Derivative Assets	(6)		(22)
Long-Term, Derivative Assets	0		(6)
Derivative Assets, Total	(6)		(28)
Short-Term, Derivative Liabilities	(6)		(22)
Long-Term, Derivative Liabilities	0		(6)
Derivative Liabilities, Total	(6)		(28)
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	(15)	[1]	(38)	[1]
Long-Term, Derivative Liabilities	(6)	[1]	(9)	[1]
Derivative Liabilities, Total	(21)	[1]	(47)	[1]
Net Liability	$ (21)	[1]	$ (47)	[1]

[1] In addition, at September 30, 2013 and December 31, 2012, SCE had posted $14 million and $8 million, respectively, of collateral that is not offset against the derivative liabilities and is reflected in "Other current assets" on the consolidated balance sheets.