Other Investments (Amortized Cost and Fair Value of Nuclear Decommissioning Trusts) (Details) (Southern California Edison, USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 30, 2014	Dec. 31, 2013
Nuclear Decommissioning Trusts Disclosures
Total Investments, Amortized Cost	$ 2,979	$ 2,770
Total Investments, Fair Value	4,741	4,494
Stocks
Nuclear Decommissioning Trusts Disclosures
Longest Maturity Dates (in years)	0
Total Investments, Amortized Cost	500	656
Total Investments, Fair Value	1,970	2,208
Municipal bonds
Nuclear Decommissioning Trusts Disclosures
Longest Maturity Dates (in years)	2051
Total Investments, Amortized Cost	663	675
Total Investments, Fair Value	807	756
U.S. government and agency securities
Nuclear Decommissioning Trusts Disclosures
Longest Maturity Dates (in years)	2045
Total Investments, Amortized Cost	826	902
Total Investments, Fair Value	888	947
Corporate bonds
Nuclear Decommissioning Trusts Disclosures
Longest Maturity Dates (in years)	2057
Total Investments, Amortized Cost	333	208
Total Investments, Fair Value	385	241
Short-term investments and receivables/payables
Nuclear Decommissioning Trusts Disclosures
Longest Maturity Dates (in years)	One-year
Total Investments, Amortized Cost	657	329
Total Investments, Fair Value	$ 691	$ 342