Debt and Credit Agreements (Credit Agreements and Short-Term Debt) (Details) (USD $) In Millions, unless otherwise specified			3 Months Ended				3 Months Ended				12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Jun. 30, 2012 Revolving credit facility maturing in May 2017	Dec. 31, 2012 Revolving credit facility maturing in May 2017	Dec. 31, 2012 Southern California Edison	Dec. 31, 2011 Southern California Edison	Jun. 30, 2012 Southern California Edison Revolving credit facility maturing in May 2017	Dec. 31, 2012 Southern California Edison Revolving credit facility maturing in May 2017	Dec. 31, 2012 Commercial paper Southern California Edison Revolving credit facility maturing in May 2017	Dec. 31, 2011 Commercial paper Southern California Edison Revolving credit facility maturing in May 2017	Dec. 31, 2012 Letters of credit Southern California Edison Revolving credit facility maturing in May 2017
Short-term Debt [Line Items]
Commitment				$ 1,250				$ 2,750
Outstanding borrowings				0				(175)
Outstanding letters of credit				0				(162)
Amount available				1,250				2,413
Credit facility termination period			5 years				5 years
Letters of credit expiration period											12 months
Short-term debt	$ 175	$ 429			$ 175	$ 419				$ 419
Weighted average interest rate (as a percent)									0.37%	0.44%