Preferred and Preference Stock of Utility (Details) (USD $) In Millions, except Share data, unless otherwise specified			12 Months Ended					12 Months Ended									12 Months Ended								1 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2011 Southern California Edison Company Preferred and Preference Stock	Dec. 31, 2010 Southern California Edison Company Preferred and Preference Stock	Dec. 31, 2011 Southern California Edison Company Cumulative preferred stock, $100 par value	Dec. 31, 2011 Southern California Edison Company Cumulative preferred stock, $25 par value	Dec. 31, 2010 Southern California Edison Company Cumulative preferred stock, $25 par value	Dec. 31, 2011 Southern California Edison Company 4.08% Series	Dec. 31, 2010 Southern California Edison Company 4.08% Series	Dec. 31, 2011 Southern California Edison Company 4.24% Series	Dec. 31, 2010 Southern California Edison Company 4.24% Series	Dec. 31, 2011 Southern California Edison Company 4.32% Series	Dec. 31, 2010 Southern California Edison Company 4.32% Series	Dec. 31, 2011 Southern California Edison Company 4.78% Series	Dec. 31, 2010 Southern California Edison Company 4.78% Series	Dec. 31, 2011 Southern California Edison Company Preference stock, no par value	Dec. 31, 2011 Southern California Edison Company 4.90% Series A	Dec. 31, 2010 Southern California Edison Company 4.90% Series A	Dec. 31, 2011 Southern California Edison Company 6.125% Series B	Dec. 31, 2010 Southern California Edison Company 6.125% Series B	Dec. 31, 2011 Southern California Edison Company 6.00% Series C	Dec. 31, 2010 Southern California Edison Company 6.00% Series C	Dec. 31, 2011 Southern California Edison Company 6.50% Series D	Dec. 31, 2010 Southern California Edison Company 6.50% Series D	Feb. 29, 2012 Southern California Edison Company 6.25% Series E Stock Issuance	Jan. 31, 2012 Southern California Edison Company 6.25% Series E Stock Issuance
Preferred and Preference Stock of Utility
Preference stock (as a percent)								4.08%	4.08%	4.24%	4.24%	4.32%	4.32%	4.78%	4.78%		4.90%	4.90%	6.125%	6.125%	6.00%	6.00%	6.50%		6.25%	6.25%
Cumulative preferred stock, par value (in dollars per share)					$ 100	$ 25	$ 25
Preferred and preference stock, shares authorized (in shares)					12,000,000	24,000,000										50,000,000
Preference share, liquidation value (in dollars per share)																$ 100									$ 1,000	$ 1,000
Shares Outstanding (in shares)								650,000	650,000	1,200,000	1,200,000	1,653,429	1,653,429	1,296,769	1,296,769		4,000,000	4,000,000	2,000,000	2,000,000	2,000,000	2,000,000	1,250,000
Redemption Price (in dollars per share)								$ 25.50	$ 25.50	$ 25.80	$ 25.80	$ 28.75	$ 28.75	$ 25.80	$ 25.80		$ 100.00	$ 100.00	$ 100.00	$ 100.00	$ 100.00	$ 100.00	$ 100.00		$ 1,000.00	$ 1,000.00
Preferred and preference stock before issuance costs			$ 1,045	$ 920				$ 16	$ 16	$ 30	$ 30	$ 41	$ 41	$ 33	$ 33		$ 400	$ 400	$ 200	$ 200	$ 200	$ 200	$ 125	$ 0
Less issuance costs			(16)	(13)
Total	1,029	907	1,029	907
Accrued dividend			$ 11
Shares issued (in shares)																									100,000	250,000