Other Investments (Amortized Cost and Fair Value of Nuclear Decommissioning Trusts) (Details) (Southern California Edison, USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Dec. 31, 2013
Nuclear Decommissioning Trusts Disclosures
Total Investments, Amortized Cost	$ 2,800	$ 2,770
Total Investments, Fair Value	4,587	4,494
Stocks
Nuclear Decommissioning Trusts Disclosures
Longest Maturity Dates (in years)	0
Total Investments, Amortized Cost	668	656
Total Investments, Fair Value	2,234	2,208
Municipal bonds
Nuclear Decommissioning Trusts Disclosures
Longest Maturity Dates (in years)	2051
Total Investments, Amortized Cost	725	675
Total Investments, Fair Value	838	756
U.S. government and agency securities
Nuclear Decommissioning Trusts Disclosures
Longest Maturity Dates (in years)	2044
Total Investments, Amortized Cost	812	902
Total Investments, Fair Value	864	947
Corporate bonds
Nuclear Decommissioning Trusts Disclosures
Longest Maturity Dates (in years)	2054
Total Investments, Amortized Cost	253	208
Total Investments, Fair Value	296	241
Short-term investments and receivables/payables
Nuclear Decommissioning Trusts Disclosures
Longest Maturity Dates (in years)	One-year
Total Investments, Amortized Cost	342	329
Total Investments, Fair Value	$ 355	$ 342