Investments (Summary of Changes in Fair Value of the Nuclear Decommissioning Trusts) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Summary Of Changes In The Fair Value [Roll Forward]
Balance at beginning of period			$ 4,799
Balance at end of period	$ 4,836		4,836
Southern California Edison
Summary Of Changes In The Fair Value [Roll Forward]
Balance at beginning of period	4,896	$ 4,587	4,799	$ 4,494
Gross realized gains	5	28	32	38
Gross realized losses	(3)	0	(5)	0
Unrealized (losses) gains, net	(71)	107	(27)	169
Other-than-temporary impairments	(8)	(3)	(12)	(6)
Interest and dividends	32	33	60	62
Contributions	0	0	7	5
Income taxes	(14)	(11)	(14)	(19)
Administrative expenses and other	(1)	(1)	(4)	(3)
Balance at end of period	$ 4,836	$ 4,740	$ 4,836	$ 4,740