Other Investments (Textual) (Details) (USD $)	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012
Other Investments [Line Items]
Proceeds from sale of securities	$ 435,000,000	$ 602,000,000
Southern California Edison
Other Investments [Line Items]
Contributions received for decommissioning trusts	23,000,000
Period of reviewing contributions from decommissioning trusts (in years)	3 years
Expected annual trust contributions approved by C.P.U.C subsequent to approved decommissioning studies	41,000,000
Proceeds from sale of securities	435,000,000	602,000,000
Unrealized holding gains, net of losses	$ 1,700,000,000		$ 1,600,000,000