Other Investments (Amortized Cost and Fair Value of Nuclear Decommissioning Trusts) (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Nuclear Decommissioning Trusts Disclosures
Fair Value		$ 4,331	$ 4,799
Southern California Edison
Nuclear Decommissioning Trusts Disclosures
Amortized Cost		2,917	3,020
Fair Value		4,331	4,799	$ 4,494	$ 4,048
Southern California Edison | Stocks
Nuclear Decommissioning Trusts Disclosures
Amortized Cost		304	524
Fair Value		$ 1,460	2,031
Southern California Edison | Municipal bonds
Nuclear Decommissioning Trusts Disclosures
Longest Maturity Dates (in years)		2054
Amortized Cost		$ 691	681
Fair Value		$ 840	822
Southern California Edison | U.S. government and agency securities
Nuclear Decommissioning Trusts Disclosures
Longest Maturity Dates (in years)		2046
Amortized Cost		$ 1,070	777
Fair Value		$ 1,128	836
Southern California Edison | Corporate bonds
Nuclear Decommissioning Trusts Disclosures
Longest Maturity Dates (in years)		2057
Amortized Cost		$ 708	346
Fair Value		$ 755	395
Southern California Edison | Short-term investments and receivables/payables
Nuclear Decommissioning Trusts Disclosures
Longest Maturity Dates (in years)	[1]	One-year
Amortized Cost	[1]	$ 144	692
Fair Value	[1]	$ 148	$ 715

[1] Short-term investments include $81 million and $164 million of repurchase agreements payable by financial institutions which earn interest, are fully secured by U.S. Treasury securities and mature by January 5, 2016 and January 7, 2015 as of December 31, 2015 and 2014, respectively.