Other Investments (Amortized Cost and Fair Value of Nuclear Decommissioning Trusts) (Details) (USD $) In Millions, unless otherwise specified							12 Months Ended		12 Months Ended		12 Months Ended		12 Months Ended		12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2012 Southern California Edison	Dec. 31, 2011 Southern California Edison	Dec. 31, 2010 Southern California Edison	Dec. 31, 2009 Southern California Edison	Dec. 31, 2012 Southern California Edison Stocks	Dec. 31, 2011 Southern California Edison Stocks	Dec. 31, 2012 Southern California Edison Municipal bonds	Dec. 31, 2011 Southern California Edison Municipal bonds	Dec. 31, 2012 Southern California Edison U.S. government and agency securities	Dec. 31, 2011 Southern California Edison U.S. government and agency securities	Dec. 31, 2012 Southern California Edison Corporate bonds	Dec. 31, 2011 Southern California Edison Corporate bonds	Dec. 31, 2012 Southern California Edison Short-term investments and receivables/payables	Dec. 31, 2011 Southern California Edison Short-term investments and receivables/payables
Nuclear Decommissioning Trusts Disclosures
Longest Maturity Dates (in years)							0		2054		2043		2054		One-year
Amortized Cost			$ 2,483	$ 2,303			$ 978	$ 865	$ 518	$ 625	$ 547	$ 516	$ 324	$ 259	$ 116	$ 38
Fair Value	$ 4,048	$ 3,592	$ 4,048	$ 3,592	$ 3,480	$ 3,140	$ 2,271	$ 1,899	$ 644	$ 756	$ 603	$ 580	$ 410	$ 317	$ 120	$ 40