Compensation and Benefit Plans (Plan Assets and Benefit Obligation) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011
Amounts recognized in the consolidated balance sheets consist of:
Long-term liabilities	$ (2,614)		$ (2,715)
Southern California Edison
Amounts recognized in the consolidated balance sheets consist of:
Long-term liabilities	(2,245)		(2,461)
Pension Plans
Change in projected benefit obligation
Benefit obligation at beginning of year	4,493		4,080
Service cost	179		165
Interest cost	196		210
Liability transferred to Edison International	23		0
Actuarial (gain) loss	370		327
Curtailment	26		0
Benefits paid	(253)		(289)
Deconsolidation of EME	(34)	[1]	0	[1]
Benefit obligation at end of year	4,948		4,493
Change in plan assets
Fair value of plan assets at beginning of year	3,153		3,235
Actual return on plan assets	460		61
Employer contributions	182		146
Benefits paid	(253)		(289)
Fair value of plan assets at end of year	3,542		3,153
Funded status at end of year	(1,406)		(1,340)
Amounts recognized in the consolidated balance sheets consist of:
Current liabilities	(19)		(11)
Long-term liabilities	(1,387)		(1,329)
Total liabilities	(1,406)		(1,340)
Amounts recognized in accumulated other comprehensive loss consist of:
Prior service cost (credit)	0		1
Net loss	127		139
Total amounts recognized in accumulated other comprehensive loss (income)	127		140
Amounts recognized as a regulatory asset (liability):
Prior service cost (credit)	30		34
Net loss	999		955
Total amounts recognized as regulatory asset	1,029		989
Total not yet recognized as expense	1,156		1,129
Accumulated benefit obligation at end of year	4,609		4,157
Pension plans with an accumulated benefit obligation in excess of plan assets:
Projected benefit obligation	4,948		4,493
Accumulated benefit obligation	4,609		4,157
Fair value of plan assets	3,542		3,153
Weighted-average assumptions used to determine obligations at end of year:
Discount rate	3.75%		4.50%
Rate of compensation increase	4.50%		4.50%
Pension Plans | Southern California Edison
Change in projected benefit obligation
Benefit obligation at beginning of year	4,112		3,732
Service cost	156		145
Interest cost	176		192
Liability transferred to Edison International	(92)		0
Actuarial (gain) loss	318		311
Curtailment	0		0
Benefits paid	(236)		(268)
Deconsolidation of EME	0	[1]	0	[1]
Benefit obligation at end of year	4,434		4,112
Change in plan assets
Fair value of plan assets at beginning of year	2,971		3,066
Actual return on plan assets	431		58
Employer contributions	154		115
Benefits paid	(236)		(268)
Fair value of plan assets at end of year	3,320		2,971
Funded status at end of year	(1,114)		(1,141)
Amounts recognized in the consolidated balance sheets consist of:
Current liabilities	(6)		(6)
Long-term liabilities	(1,108)		(1,135)
Total liabilities	(1,114)		(1,141)
Amounts recognized in accumulated other comprehensive loss consist of:
Prior service cost (credit)	0		0
Net loss	40		41
Total amounts recognized in accumulated other comprehensive loss (income)	40		41
Amounts recognized as a regulatory asset (liability):
Prior service cost (credit)	30		34
Net loss	999		955
Total amounts recognized as regulatory asset	1,029		989
Total not yet recognized as expense	1,069		1,030
Accumulated benefit obligation at end of year	4,171		3,817
Pension plans with an accumulated benefit obligation in excess of plan assets:
Projected benefit obligation	4,434		4,112
Accumulated benefit obligation	4,171		3,817
Fair value of plan assets	3,320		2,971
Weighted-average assumptions used to determine obligations at end of year:
Discount rate	3.75%		4.50%
Rate of compensation increase	4.50%		4.50%
Postretirement Benefits Other Than Pensions
Change in projected benefit obligation
Benefit obligation at beginning of year	2,553		2,425
Service cost	47		43
Interest cost	108		121
Other costs	2		0
Actuarial (gain) loss	(86)		47
Plan participants' contributions	16		18
Medicare Part D subsidy received	4		5
Benefits paid	(54)		(106)
Deconsolidation of EME	(130)	[2]	0	[2]
Benefit obligation at end of year	2,460		2,553
Change in plan assets
Fair value of plan assets at beginning of year	1,570		1,606
Actual return on plan assets	212		11
Employer contributions	52		36
Plan participants' contributions	16		18
Medicare Part D subsidy received	4		5
Benefits paid	(54)		(106)
Fair value of plan assets at end of year	1,800		1,570
Funded status at end of year	(660)		(983)
Amounts recognized in the consolidated balance sheets consist of:
Current liabilities	(18)		(19)
Long-term liabilities	(642)		(964)
Total liabilities	(660)		(983)
Amounts recognized in accumulated other comprehensive loss consist of:
Prior service cost (credit)	0		8
Net loss	5		27
Total amounts recognized in accumulated other comprehensive loss (income)	5		35
Amounts recognized as a regulatory asset (liability):
Prior service cost (credit)	(89)		(125)
Net loss	610		839
Total amounts recognized as regulatory asset	521		714
Total not yet recognized as expense	526		749
Weighted-average assumptions used to determine obligations at end of year:
Discount rate	4.25%		4.75%
Rate assumed for following year	8.50%		9.50%
Ultimate rate	5.00%		5.25%
Year ultimate rate reached	2020		2019
Postretirement Benefits Other Than Pensions | Southern California Edison
Change in projected benefit obligation
Benefit obligation at beginning of year	2,415		2,295
Service cost	47		40
Interest cost	108		114
Other costs	2		0
Actuarial (gain) loss	(86)		46
Plan participants' contributions	16		18
Medicare Part D subsidy received	4		5
Benefits paid	(54)		(103)
Deconsolidation of EME	0	[2]	0	[2]
Benefit obligation at end of year	2,452		2,415
Change in plan assets
Fair value of plan assets at beginning of year	1,570		1,606
Actual return on plan assets	212		10
Employer contributions	52		34
Plan participants' contributions	16		18
Medicare Part D subsidy received	4		5
Benefits paid	(54)		(103)
Fair value of plan assets at end of year	1,800		1,570
Funded status at end of year	(652)		(845)
Amounts recognized in the consolidated balance sheets consist of:
Current liabilities	(18)		(16)
Long-term liabilities	(634)		(829)
Total liabilities	(652)		(845)
Amounts recognized in accumulated other comprehensive loss consist of:
Prior service cost (credit)	0		0
Net loss	0		0
Total amounts recognized in accumulated other comprehensive loss (income)	0		0
Amounts recognized as a regulatory asset (liability):
Prior service cost (credit)	(89)		(125)
Net loss	610		839
Total amounts recognized as regulatory asset	521		714
Total not yet recognized as expense	$ 521		$ 714
Weighted-average assumptions used to determine obligations at end of year:
Discount rate	4.25%		4.75%
Rate assumed for following year	8.50%		9.50%
Ultimate rate	5.00%		5.25%
Year ultimate rate reached	2020		2019

[1] The retirement plan liabilities of EME have been deconsolidated as a result of the bankruptcy filing by EME, except for qualified pension plans that Edison International is jointly liable with EME under the Internal Revenue Code. See Note 17 for further information.

[2] The postretirement plan liabilities of EME have been deconsolidated as a result of the bankruptcy filing by EME. See Note 17 for further information.