Other Investments (Summary of Changes in Fair Value of the Nuclear Decommissioning Trusts) (Details) (USD $) In Millions, unless otherwise specified			3 Months Ended		6 Months Ended
	Jun. 30, 2013	Dec. 31, 2012	Jun. 30, 2013 Southern California Edison	Jun. 30, 2012 Southern California Edison	Jun. 30, 2013 Southern California Edison	Jun. 30, 2012 Southern California Edison
Summary Of Changes In The Fair Value [Roll Forward]
Balance at beginning of period	$ 4,181	$ 4,048	$ 4,246	$ 3,853	$ 4,048	$ 3,592
Gross realized gains			137	15	142	40
Gross realized losses			(1)	(1)	(2)	(5)
Unrealized gains, net			(185)	(67)	(9)	116
Other-than-temporary impairments			(21)	(19)	(29)	(23)
Interest, dividends, contributions and other			5	29	31	90
Balance at end of period	$ 4,181	$ 4,048	$ 4,181	$ 3,810	$ 4,181	$ 3,810