Consolidated Statements of Comprehensive Income (Parenthetical) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Net gain (loss) arising during the period, tax	$ 32	$ (14)	$ (22)
Amortization of net (gain) loss included in net income (loss), tax	(2)	5	4
Net prior service cost (credit) arising during the period, tax	1	0	(4)
Amortization of prior service cost (credit) included in net income (loss), tax	2	0	0
Unrealized holding gain (loss) arising during the period, tax	(15)	(7)	37
Reclassification adjustments included in net income (loss), tax	37	(25)	(96)
Southern California Edison
Net gain (loss) arising during the period, tax	(6)	(2)	(6)
Amortization of net (gain) loss included in net income (loss), tax	$ 3	$ 2	$ 2