Quarterly Financial Data (Unaudited) (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended												12 Months Ended
	Dec. 31, 2012		Sep. 30, 2012		Jun. 30, 2012		Mar. 31, 2012		Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012		Dec. 31, 2011	Dec. 31, 2010
Quarterly Financial Data [Line Items]
Operating revenue	$ 3,060		$ 3,734		$ 2,653		$ 2,415		$ 2,517	$ 3,389	$ 2,449	$ 2,233	$ 11,862		$ 10,588	$ 9,996
Operating income	765		714		420		389		440	755	434	433	2,285		2,061	1,819
Net income													(92)		22	1,308
Income from continuing operations	812	[1],[2]	382	[1],[2]	207	[1],[2]	196	[1],[2]	236	408	223	234	1,594	[1],[2]	1,100	1,144
Income (loss) from discontinued operations, net of tax	(1,326)	[3]	(167)	[3]	(109)	[3]	(84)	[3]	(1,060)	33	(32)	(20)	(1,686)	[3]	(1,078)	164
Net income attributable to common shareholders	(539)		190		74		93		(839)	426	176	200	(183)		(37)	1,256
Earnings benefit from implementation of 2012 GRC Decision	500
Immaterial error correction	33
Basic earnings (loss) per share:
Basic earnings (loss) per share – continuing operations (in dollars per share)	$ 2.42		$ 1.09		$ 0.57		$ 0.54		$ 0.68	$ 1.21	$ 0.64	$ 0.67	$ 4.61		$ 3.20	$ 3.34
Basic earnings (loss) per share – discontinued operations (in dollars per share)	$ (4.07)		$ (0.51)		$ (0.34)		$ (0.26)		$ (3.25)	$ 0.10	$ (0.10)	$ (0.06)	$ (5.17)		$ (3.31)	$ 0.50
Total basic earnings (loss) per share (in dollars per share)	$ (1.65)		$ 0.58		$ 0.23		$ 0.28		$ (2.57)	$ 1.31	$ 0.54	$ 0.61	$ (0.56)		$ (0.11)	$ 3.84
Diluted earnings (loss) per share:
Diluted earnings (loss) per share – continuing operations (in dollars per share)	$ 2.39		$ 1.09		$ 0.55		$ 0.54		$ 0.66	$ 1.20	$ 0.64	$ 0.67	$ 4.55		$ 3.17	$ 3.32
Diluted earnings (loss) per share – discontinued operations (in dollars per share)	$ (4.03)		$ (0.51)		$ (0.33)		$ (0.26)		$ (3.22)	$ 0.10	$ (0.10)	$ (0.06)	$ (5.11)		$ (3.28)	$ 0.50
Total diluted earnings (loss) per share (in dollars per share)	$ (1.64)		$ 0.58		$ 0.22		$ 0.28		$ (2.56)	$ 1.30	$ 0.54	$ 0.61	$ (0.56)		$ (0.11)	$ 3.82
Dividends declared per share (in dollars per share)	$ 0.3375		$ 0.325		$ 0.325		$ 0.325		$ 0.325	$ 0.320	$ 0.320	$ 0.320	$ 1.3125		$ 1.285	$ 1.265
Common stock prices:
High	$ 47.96		$ 46.94		$ 46.55		$ 44.50		$ 41.57	$ 39.25	$ 40.15	$ 39.20	$ 47.96		$ 41.57
Low	$ 42.57		$ 43.10		$ 41.42		$ 39.60		$ 35.63	$ 32.64	$ 36.54	$ 35.12	$ 39.60		$ 32.64
Close	$ 45.19		$ 45.69		$ 46.20		$ 42.51		$ 41.40	$ 38.25	$ 38.75	$ 36.59	$ 45.19		$ 41.40
Edison Mission Energy
Quarterly Financial Data [Line Items]
Impairment and other charges	1,200												1,200
Southern California Edison
Quarterly Financial Data [Line Items]
Operating revenue	3,057		3,731		2,651		2,412		2,514	3,386	2,446	2,232	11,851		10,577	9,983
Operating income	792		659		430		397		474	764	443	443	2,279		2,123	1,864
Net income	858	[1],[2]	388	[1],[2]	214	[1],[2]	201	[1],[2]	262	421	226	236	1,660	[1],[2]	1,144	1,092
Net income attributable to common shareholders	833		363		191		182		247	406	211	222	1,569		1,085	1,040
Earnings benefit from implementation of 2012 GRC Decision	500
Immaterial error correction	33
Diluted earnings (loss) per share:
Common dividends declared	$ 120		$ 116		$ 116		$ 116		$ 116	$ 115	$ 115	$ 115	$ 469		$ 461

[1] During the fourth quarter of 2012, SCE corrected errors, primarily related to deferred taxes, that resulted in a net earnings benefit of $33 million which were not considered material to the current and prior period consolidated financial statements.

[2] During the fourth quarter of 2012, SCE implemented the 2012 GRC Decision which resulted in an earnings impact of approximately $500 million.

[3] During the fourth quarter of 2012, Edison International recorded a full impairment of its $1.2 billion investment in EME. See Note 17 for further information.