Income Taxes (Interest and Penalties Related to Income Taxes) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Income Tax Disclosure [Line Items]
Accrued interest and penalties	$ 278	$ 242
Net after-tax interest and penalties tax benefit (expense)	(10)	(8)	166
Southern California Edison
Income Tax Disclosure [Line Items]
Accrued interest and penalties	87	75
Net after-tax interest and penalties tax benefit (expense)	$ (11)	$ (8)	$ 80