Schedule I - Condensed Financial Information of Parent (Details) (USD $) Share data 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	Dec. 31, 2009
Assets:
Cash and cash equivalents	$ 170,000,000								$ 1,469,000,000				$ 170,000,000		$ 1,469,000,000	$ 1,389,000,000
Other current assets	119,000,000								73,000,000				119,000,000		73,000,000
Total current assets	2,672,000,000								4,484,000,000				2,672,000,000		4,484,000,000
Investments in subsidiaries	2,000,000								2,000,000				2,000,000		2,000,000
Other	704,000,000								486,000,000				704,000,000		486,000,000
Total assets	44,394,000,000								48,039,000,000				44,394,000,000		48,039,000,000
Liabilities and Shareholders' Equity:
Accounts payable	1,423,000,000								1,321,000,000				1,423,000,000		1,321,000,000
Other current liabilities	990,000,000								794,000,000				990,000,000		794,000,000
Total current liabilities	3,744,000,000								4,348,000,000				3,744,000,000		4,348,000,000
Long-term debt	9,231,000,000								8,834,000,000				9,231,000,000		8,834,000,000
Common stockholders' equity	11,191,000,000								11,086,000,000				11,191,000,000		11,086,000,000	11,494,000,000	11,006,000,000
Total liabilities and equity	44,394,000,000								48,039,000,000				44,394,000,000		48,039,000,000
Condensed Statements of Income:
Operating revenue and other income	3,060,000,000		3,734,000,000		2,653,000,000		2,415,000,000		2,517,000,000	3,389,000,000	2,449,000,000	2,233,000,000	11,862,000,000		10,588,000,000	9,996,000,000
Operating expenses and interest expense													9,577,000,000		8,527,000,000	8,177,000,000
Loss before equity in earnings of subsidiaries	765,000,000		714,000,000		420,000,000		389,000,000		440,000,000	755,000,000	434,000,000	433,000,000	2,285,000,000		2,061,000,000	1,819,000,000
Equity in earnings (loss) of subsidiaries													1,000,000		0	2,000,000
Income tax expense (benefit)													267,000,000		568,000,000	335,000,000
Income (Loss) from Continuing Operations, Including Portion Attributable to Noncontrolling Interest	812,000,000	[1],[2]	382,000,000	[1],[2]	207,000,000	[1],[2]	196,000,000	[1],[2]	236,000,000	408,000,000	223,000,000	234,000,000	1,594,000,000	[1],[2]	1,100,000,000	1,144,000,000
Income (loss) from discontinued operations, net of tax	(1,326,000,000)	[3]	(167,000,000)	[3]	(109,000,000)	[3]	(84,000,000)	[3]	(1,060,000,000)	33,000,000	(32,000,000)	(20,000,000)	(1,686,000,000)	[3]	(1,078,000,000)	164,000,000
Net income (loss)													(92,000,000)		22,000,000	1,308,000,000
Other comprehensive income (loss)													52,000,000		(63,000,000)	(113,000,000)
Comprehensive income (loss)													(131,000,000)		(100,000,000)	1,143,000,000
Weighted-average shares of common stock outstanding (in shares)													326		326	326
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 (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 – 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 (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
Condensed Statements of Cash Flows:
Net cash provided by operating activities													3,334,000,000		3,906,000,000	3,477,000,000
Cash flows from financing activities:
Long-term debt issued													395,000,000		896,000,000	1,535,000,000
Long-term debt issuance costs													(4,000,000)		(9,000,000)	(19,000,000)
Short-term debt financing, net													(264,000,000)		410,000,000	(66,000,000)
Settlements of stock-based compensation, net													(68,000,000)		(15,000,000)	(13,000,000)
Dividends paid													(424,000,000)		(417,000,000)	(411,000,000)
Net cash provided by financing activities													650,000,000		1,107,000,000	1,053,000,000
Net cash provided by investing activities:													(5,283,000,000)		(4,933,000,000)	(4,814,000,000)
Net increase in cash and cash equivalents													(1,299,000,000)		80,000,000	(284,000,000)
Cash and cash equivalents at beginning of year							1,469,000,000					1,389,000,000	1,469,000,000		1,389,000,000	1,673,000,000
Cash and cash equivalents at end of year	170,000,000								1,469,000,000				170,000,000		1,469,000,000	1,389,000,000
Debt and Credit Agreements
Short-term debt	175,000,000								429,000,000				175,000,000		429,000,000
Consolidated debt to total capitalization, ratio	0.65												0.65
Senior Notes Due 2017
Debt and Credit Agreements
Interest rate on debt (as a percent)	3.75%												3.75%
Senior notes	400,000,000												400,000,000
Revolving credit facility maturing in May 2017
Debt and Credit Agreements
Credit facility termination period					5 years
Commitment	1,250,000,000												1,250,000,000
Outstanding borrowings	0												0
Amount available	1,250,000,000												1,250,000,000
Edison International
Assets:
Cash and cash equivalents	64,000,000								28,000,000				64,000,000		28,000,000	21,000,000
Other current assets	18,000,000								236,000,000				18,000,000		236,000,000
Total current assets	82,000,000								264,000,000				82,000,000		264,000,000
Investments in subsidiaries	9,903,000,000								10,511,000,000				9,903,000,000		10,511,000,000
Deferred income tax	555,000,000								150,000,000				555,000,000		150,000,000
Other	414,000,000								192,000,000				414,000,000		192,000,000
Total assets	10,954,000,000								11,117,000,000				10,954,000,000		11,117,000,000
Liabilities and Shareholders' Equity:
Accounts payable	105,000,000								4,000,000				105,000,000		4,000,000
Other current liabilities	184,000,000								448,000,000				184,000,000		448,000,000
Total current liabilities	289,000,000								452,000,000				289,000,000		452,000,000
Long-term debt	400,000,000								400,000,000				400,000,000		400,000,000
Other	833,000,000								210,000,000				833,000,000		210,000,000
Common stockholders' equity	9,432,000,000								10,055,000,000				9,432,000,000		10,055,000,000
Total liabilities and equity	10,954,000,000								11,117,000,000				10,954,000,000		11,117,000,000
Condensed Statements of Income:
Operating revenue and other income													0		0	0
Operating expenses and interest expense													80,000,000		63,000,000	56,000,000
Loss before equity in earnings of subsidiaries													(80,000,000)		(63,000,000)	(56,000,000)
Equity in earnings (loss) of subsidiaries													1,590,000,000		1,077,000,000	1,098,000,000
Income before income taxes													1,510,000,000		1,014,000,000	1,042,000,000
Income tax expense (benefit)													7,000,000		(27,000,000)	(50,000,000)
Income (Loss) from Continuing Operations, Including Portion Attributable to Noncontrolling Interest													1,503,000,000		1,041,000,000	1,092,000,000
Income (loss) from discontinued operations, net of tax													(1,686,000,000)		(1,078,000,000)	164,000,000
Net income (loss)													(183,000,000)		(37,000,000)	1,256,000,000
Other comprehensive income (loss)													52,000,000		(63,000,000)	(113,000,000)
Comprehensive income (loss)													(131,000,000)		(100,000,000)	1,143,000,000
Weighted-average shares of common stock outstanding (in shares)													326		326	326
Basic earnings (loss) per share – continuing operations (in dollars per share)													$ 4.61		$ 3.20	$ 3.34
Basic earnings (loss) per share – discontinued operations (in dollars per share)													$ (5.17)		$ (3.31)	$ 0.50
Total (in dollars per share)													$ (0.56)		$ (0.11)	$ 3.84
Diluted earnings (loss) per share – continuing operations (in dollars per share)													$ 4.55		$ 3.17	$ 3.32
Diluted earnings (loss) per share – discontinued operations (in dollars per share)													$ (5.11)		$ (3.28)	$ 0.50
Total (in dollars per share)													$ (0.56)		$ (0.11)	$ 3.82
Condensed Statements of Cash Flows:
Net cash provided by operating activities													355,000,000		437,000,000	90,000,000
Cash flows from financing activities:
Long-term debt issued													0		0	399,000,000
Long-term debt issuance costs													0		0	(3,000,000)
Payable due to consolidated affiliate													130,000,000		0	0
Short-term debt financing, net													(15,000,000)		(9,000,000)	(66,000,000)
Settlements of stock-based compensation, net													(10,000,000)		(5,000,000)	(6,000,000)
Dividends paid													(424,000,000)		(417,000,000)	(411,000,000)
Net cash provided by financing activities													(319,000,000)		(431,000,000)	(87,000,000)
Net cash provided by investing activities:													0		1,000,000	0
Net increase in cash and cash equivalents													36,000,000		7,000,000	3,000,000
Cash and cash equivalents at beginning of year							28,000,000					21,000,000	28,000,000		21,000,000	18,000,000
Cash and cash equivalents at end of year	64,000,000								28,000,000				64,000,000		28,000,000	21,000,000
Dividends [Abstract]
Minimum percentage of weighted-average common equity component authorization, set by CPUC (as a percent)													48.00%
Cash dividends received from consolidated subsidiaries													469,000,000		461,000,000	300,000,000
Debt and Credit Agreements
Consolidated debt to total capitalization, ratio	0.46												0.46
Related Party Transactions
Current receivables due from affiliates	23,000,000								219,000,000				23,000,000		219,000,000
Current payables due to affiliates	146,000,000								106,000,000				146,000,000		106,000,000
Long-term receivables due from affiliate	322,000,000												322,000,000
Long-term payables due to affiliates	112,000,000								98,000,000				112,000,000		98,000,000
Edison International | Revolving credit facility maturing in May 2017
Debt and Credit Agreements
Short-term debt									10,000,000						10,000,000
Weighted average interest rate (as a percent)									0.66%						0.66%
Amount available	1,250,000,000												1,250,000,000
Southern California Edison
Assets:
Cash and cash equivalents	45,000,000								57,000,000				45,000,000		57,000,000	257,000,000
Other current assets	123,000,000								89,000,000				123,000,000		89,000,000
Total current assets	2,562,000,000								2,612,000,000				2,562,000,000		2,612,000,000
Other	531,000,000								491,000,000				531,000,000		491,000,000
Total assets	44,034,000,000								40,315,000,000				44,034,000,000		40,315,000,000
Liabilities and Shareholders' Equity:
Accounts payable	1,297,000,000								1,319,000,000				1,297,000,000		1,319,000,000
Other current liabilities	861,000,000								670,000,000				861,000,000		670,000,000
Total current liabilities	3,513,000,000								3,848,000,000				3,513,000,000		3,848,000,000
Long-term debt	8,828,000,000								8,431,000,000				8,828,000,000		8,431,000,000
Common stockholders' equity	11,743,000,000								9,958,000,000				11,743,000,000		9,958,000,000	9,207,000,000	8,715,000,000
Total liabilities and equity	44,034,000,000								40,315,000,000				44,034,000,000		40,315,000,000
Condensed Statements of Income:
Operating revenue and other income	3,057,000,000		3,731,000,000		2,651,000,000		2,412,000,000		2,514,000,000	3,386,000,000	2,446,000,000	2,232,000,000	11,851,000,000		10,577,000,000	9,983,000,000
Operating expenses and interest expense													9,572,000,000		8,454,000,000	8,119,000,000
Loss before equity in earnings of subsidiaries	792,000,000		659,000,000		430,000,000		397,000,000		474,000,000	764,000,000	443,000,000	443,000,000	2,279,000,000		2,123,000,000	1,864,000,000
Income tax expense (benefit)													214,000,000		601,000,000	440,000,000
Net income (loss)	858,000,000	[1],[2]	388,000,000	[1],[2]	214,000,000	[1],[2]	201,000,000	[1],[2]	262,000,000	421,000,000	226,000,000	236,000,000	1,660,000,000	[1],[2]	1,144,000,000	1,092,000,000
Other comprehensive income (loss)													(5,000,000)		1,000,000	(6,000,000)
Condensed Statements of Cash Flows:
Net cash provided by operating activities													4,086,000,000		3,261,000,000	3,386,000,000
Cash flows from financing activities:
Long-term debt issued													395,000,000		896,000,000	1,135,000,000
Long-term debt issuance costs													(4,000,000)		(9,000,000)	(16,000,000)
Short-term debt financing, net													(250,000,000)		419,000,000	0
Settlements of stock-based compensation, net													(57,000,000)		(10,000,000)	(5,000,000)
Dividends paid													(551,000,000)		(520,000,000)	(352,000,000)
Net cash provided by financing activities													256,000,000		799,000,000	503,000,000
Net cash provided by investing activities:													(4,354,000,000)		(4,260,000,000)	(4,094,000,000)
Net increase in cash and cash equivalents													(12,000,000)		(200,000,000)	(205,000,000)
Cash and cash equivalents at beginning of year							57,000,000					257,000,000	57,000,000		257,000,000	462,000,000
Cash and cash equivalents at end of year	45,000,000								57,000,000				45,000,000		57,000,000	257,000,000
Dividends [Abstract]
Weighted-average common equity component authorization, set by CPUC remaining over number of months (in months)													13 months
Period for calculation of weighted average common equity component (months)													13 months
Weighted-average common equity component of total capitalization (as a percent)													48.60%
Restriction on net assets	11,600,000,000												11,600,000,000
Capacity to pay additional dividends													125,000,000
Debt and Credit Agreements
Short-term debt	175,000,000								419,000,000				175,000,000		419,000,000
Southern California Edison | Revolving credit facility maturing in May 2017
Debt and Credit Agreements
Credit facility termination period					5 years
Commitment	2,750,000,000												2,750,000,000
Outstanding borrowings	(175,000,000)												(175,000,000)
Amount available	2,413,000,000												2,413,000,000
Southern California Edison | Edison International
Related Party Transactions
Expenses from services provided by SCE													4,000,000		3,000,000	3,000,000
Edison Mission Energy
Assets:
Investments in subsidiaries	0												0
Edison Mission Energy | Edison International
Related Party Transactions
Impairment and other charges, after tax	$ 1,258,000,000

[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.