Investments (Summary of Changes in Fair Value of the Nuclear Decommissioning Trusts) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Summary Of Changes In The Fair Value [Roll Forward]
Balance at beginning of period			$ 4,799
Balance at end of period	$ 4,388		4,388
Southern California Edison
Summary Of Changes In The Fair Value [Roll Forward]
Balance at beginning of period	4,836	$ 4,740	4,799	$ 4,494
Gross realized gains	183	149	215	187
Gross realized losses	(10)	0	(15)	0
Unrealized (losses) gains, net	(316)	(131)	(343)	38
Other-than-temporary impairments	(10)	(4)	(22)	(10)
Interest and dividends	28	28	88	90
Contributions	0	0	7	6
Income taxes	0	(40)	(14)	(59)
Decommissioning disbursements	(319)	0	(319)	(1)
Administrative expenses and other	(4)	(1)	(8)	(4)
Balance at end of period	$ 4,388	$ 4,741	$ 4,388	$ 4,741