Summary of Significant Accounting Policies (Details) (USD $)	1 Months Ended	12 Months Ended					3 Months Ended	12 Months Ended
	Nov. 30, 2012 Southern California Edison	Dec. 31, 2012 Southern California Edison	Dec. 31, 2011 Southern California Edison	Dec. 31, 2010 Southern California Edison	Dec. 31, 2012 Edison International	Dec. 31, 2012 Edison Mission Energy	Dec. 31, 2012 Edison Mission Energy Edison International	Dec. 31, 2012 Electric Utility Southern California Edison sqmi
Summary of Significant Accounting Policies [Line Items]
Number of days after bankruptcy filing for settlement transaction (days)						150 days
Impairment and other charges, after tax							$ 1,258,000,000
Supply of electricity, area covered (square mile)								50,000
Revenue Recognition [Abstract]
Base rate revenue requirement authorized by CPUC	5,700,000,000
Increase in base rate revenue requirement authorized By CPUC		470,000,000
Revenue collected in excess of recognized revenues		106,000,000
Revenue received as agent		44,000,000	1,100,000,000	1,200,000,000
Sales and Use Taxes [Abstract]
Franchise fees billed to customers		98,000,000	101,000,000	102,000,000
Dividend Restrictions [Abstract]
Minimum percentage of weighted-average common equity component authorization, set by CPUC (as a percent)					48.00%
Weighted-average common equity component authorization, set by CPUC remaining over number of months (in months)		13 months
Period for calculation of weighted average common equity component (months)		13 months
Weighted-average common equity component of total capitalization (as a percent)		48.60%
Restriction on net assets		11,600,000,000
Capacity to pay additional dividends		$ 125,000,000