Investments (Amortized Cost and Fair Value of Nuclear Decommissioning Trusts) (Details) - Southern California Edison - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2015	Dec. 31, 2014
Nuclear Decommissioning Trusts Disclosures
Amortized Cost	$ 3,085	$ 3,020
Fair Value	$ 4,836	4,799
Stocks
Nuclear Decommissioning Trusts Disclosures
Maturity Dates Decommissioning Trust Investments	0
Amortized Cost	$ 560	524
Fair Value	$ 2,084	2,031
Municipal bonds
Nuclear Decommissioning Trusts Disclosures
Maturity Dates Decommissioning Trust Investments	2054
Amortized Cost	$ 705	681
Fair Value	$ 826	822
U.S. government and agency securities
Nuclear Decommissioning Trusts Disclosures
Maturity Dates Decommissioning Trust Investments	2045
Amortized Cost	$ 1,116	777
Fair Value	$ 1,173	836
Corporate bonds
Nuclear Decommissioning Trusts Disclosures
Maturity Dates Decommissioning Trust Investments	2057
Amortized Cost	$ 591	346
Fair Value	637	395
Short-term investments and receivables/payables
Fair Value Disclosures:
Repurchase agreement	$ 140
Nuclear Decommissioning Trusts Disclosures
Longest Maturity Dates	1 year
Amortized Cost	$ 113	692
Fair Value	$ 116	$ 715