Compensation and Benefit Plans (Plan Assets and Benefit Obligation) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2008
Amounts recognized in the consolidated balance sheets:
Liabilities Subject to Compromise, Pension and Other Postretirement Obligations	$ (108)		$ (73)
Assumed health care cost trend rates:
Loss Contingency, Settlement Agreement, Consideration	22
Loss Contingency, Settlement Agreement, Percent	55.00%
Midwest Generation LLC [Member]
Amounts recognized in the consolidated balance sheets:
Liabilities Subject to Compromise, Pension and Other Postretirement Obligations	(53)		(53)
Pension Plans
Pension and Other Postretirement Benefits
Expected contribution by employer in the next fiscal year	16
Percentage of decline in market value of investments held in trust (as a percent)					35.00%
Change in projected benefit obligation
Projected benefit obligation at beginning of year	330		316
Service cost	14		16
Interest cost	14		14
Actuarial (gain) / loss	(24)		27
Curtailment (gain)/loss	0	[1]
Transfers out	(7)	[2]	(23)	[2]
Benefits paid	(29)		(11)
Projected benefit obligation at end of year	298		330
Change in plan assets
Fair value of plan assets at beginning of period	215		177
Actual return on plan assets	35		26
Employer contributions	14		23
Benefits paid	(29)		(11)
Fair value of plan assets at end of period	235		215
Funded status at end of year	(63)		(115)
Amounts recognized in the consolidated balance sheets:
Long-term liabilities	(57)		(115)
Liabilities Subject to Compromise, Pension and Other Postretirement Obligations	(6)		0
Amounts recognized in accumulated other comprehensive income:
Prior service cost (credit)	0		1
Net loss	19		67
Accumulated benefit obligation at end of year	278		300
Pension plans with an accumulated benefit obligation in excess of plan assets:
Projected benefit obligation	298		330
Accumulated benefit obligation	278		300
Fair value of plan assets	235		215
Weighted-average assumptions used to determine obligations at end of year:
Discount rate	4.75%		4.50%
Rate of compensation increase	4.00%		4.50%
Pension Plans | Midwest Generation LLC [Member]
Pension and Other Postretirement Benefits
Expected contribution by employer in the next fiscal year	12
Change in projected benefit obligation
Projected benefit obligation at beginning of year	225		195
Service cost	12		14
Interest cost	9		8
Actuarial (gain) / loss	(22)		13
Curtailment (gain)/loss	0		0
Transfers out	0	[2]	0	[2]
Benefits paid	(14)		(5)
Projected benefit obligation at end of year	210		225
Change in plan assets
Fair value of plan assets at beginning of period	149		121
Actual return on plan assets	24		19
Employer contributions	8		14
Benefits paid	(14)		(5)
Fair value of plan assets at end of period	167		149
Funded status at end of year	(43)		(76)
Amounts recognized in the consolidated balance sheets:
Long-term liabilities	(43)		(76)
Liabilities Subject to Compromise, Pension and Other Postretirement Obligations	0		0
Amounts recognized in accumulated other comprehensive income:
Prior service cost (credit)	0		1
Net loss	2		40
Accumulated benefit obligation at end of year	189		195
Pension plans with an accumulated benefit obligation in excess of plan assets:
Projected benefit obligation	210		225
Accumulated benefit obligation	189		195
Fair value of plan assets	167		149
Weighted-average assumptions used to determine obligations at end of year:
Discount rate	4.75%		4.50%
Rate of compensation increase	4.00%		4.50%
Pension Plans | Other EME Subsidiaries
Change in projected benefit obligation
Projected benefit obligation at beginning of year	105	[1]	121	[1]
Service cost	2	[1]	2	[1]
Interest cost	5	[1]	6	[1]
Actuarial (gain) / loss	(2)	[1]	14	[1]
Curtailment (gain)/loss	0	[1]	(9)	[1]
Transfers out	(7)	[1],[2]	(23)	[1],[2]
Benefits paid	(15)	[1]	(6)	[1]
Projected benefit obligation at end of year	88	[1]	105	[1]
Change in plan assets
Fair value of plan assets at beginning of period	66	[1]	56	[1]
Actual return on plan assets	11	[1]	7	[1]
Employer contributions	6	[1]	9	[1]
Benefits paid	(15)	[1]	(6)	[1]
Fair value of plan assets at end of period	68	[1]	66	[1]
Funded status at end of year	(20)	[1]	(39)	[1]
Amounts recognized in the consolidated balance sheets:
Long-term liabilities	(14)	[1]	(39)	[1]
Liabilities Subject to Compromise, Pension and Other Postretirement Obligations	(6)	[1]	0	[1]
Amounts recognized in accumulated other comprehensive income:
Prior service cost (credit)	0	[1]	0	[1]
Net loss	17	[1]	27	[1]
Accumulated benefit obligation at end of year	89	[1]	105	[1]
Pension plans with an accumulated benefit obligation in excess of plan assets:
Projected benefit obligation	88	[1]	105	[1]
Accumulated benefit obligation	89	[1]	105	[1]
Fair value of plan assets	68	[1]	66	[1]
Weighted-average assumptions used to determine obligations at end of year:
Discount rate	4.75%	[1]	4.50%	[1]
Rate of compensation increase	4.00%	[1]	4.50%	[1]
Postretirement Benefits Other Than Pensions
Pension and Other Postretirement Benefits
Eligibility age (in years)	55 years
Minimum service period for eligibility (in years)	10 years
Expected contribution by employer in the next fiscal year	3
Change in projected benefit obligation
Projected benefit obligation at beginning of year	128		130
Service cost	2		3
Interest cost	4		6
Withdrawal1	(31)		0
Actuarial (gain) / loss	(10)		(8)
Benefits paid	(2)		(3)
Projected benefit obligation at end of year	91		128
Change in plan assets
Fair value of plan assets at beginning of period	0		0
Employer contributions	2		3
Benefits paid	(2)		(3)
Fair value of plan assets at end of period	0		0
Funded status at end of year	(91)		(128)
Amounts recognized in the consolidated balance sheets:
Long-term liabilities	(91)		(128)
Amounts recognized in accumulated other comprehensive income:
Prior service cost (credit)	9		8
Net loss	1		14
Weighted-average assumptions used to determine obligations at end of year:
Discount rate	5.00%		4.25%
Assumed health care cost trend rates:
Rate assumed for following year	7.75%		8.50%
Ultimate rate	5.00%		5.00%
Year ultimate rate reached	2020		2020
Postretirement Benefits Other Than Pensions | Midwest Generation LLC [Member]
Pension and Other Postretirement Benefits
Eligibility age (in years)	55 years
Minimum service period for eligibility (in years)	10 years
Expected contribution by employer in the next fiscal year	2
Change in projected benefit obligation
Projected benefit obligation at beginning of year	59		59
Service cost	1		1
Interest cost	3		3
Withdrawal1	0		0
Actuarial (gain) / loss	(7)		(3)
Benefits paid	(1)		(1)
Projected benefit obligation at end of year	55		59
Change in plan assets
Fair value of plan assets at beginning of period	0		0
Employer contributions	1		1
Benefits paid	(1)		(1)
Fair value of plan assets at end of period	0		0
Funded status at end of year	(55)		(59)
Amounts recognized in the consolidated balance sheets:
Long-term liabilities	(55)		(59)
Amounts recognized in accumulated other comprehensive income:
Prior service cost (credit)	9		10
Net loss	2		9
Weighted-average assumptions used to determine obligations at end of year:
Discount rate	5.00%		4.25%
Assumed health care cost trend rates:
Rate assumed for following year	7.75%		8.50%
Ultimate rate	5.00%		5.00%
Year ultimate rate reached	2020		2020
Postretirement Benefits Other Than Pensions | Homer City
Amounts recognized in the consolidated balance sheets:
Long-term liabilities			31
Postretirement Benefits Other Than Pensions | Other EME Subsidiaries
Change in projected benefit obligation
Projected benefit obligation at beginning of year	69	[3]	71	[3]
Service cost	1	[3]	2	[3]
Interest cost	1	[3]	3	[3]
Withdrawal1	(31)		0
Actuarial (gain) / loss	(3)	[3]	(5)	[3]
Benefits paid	(1)	[3]	(2)	[3]
Projected benefit obligation at end of year	36	[3]	69	[3]
Change in plan assets
Fair value of plan assets at beginning of period	0	[3]	0	[3]
Employer contributions	1	[3]	2	[3]
Benefits paid	(1)	[3]	(2)	[3]
Fair value of plan assets at end of period	0	[3]	0	[3]
Funded status at end of year	(36)	[3]	(69)	[3]
Amounts recognized in the consolidated balance sheets:
Long-term liabilities	(36)	[3]	(69)	[3]
Amounts recognized in accumulated other comprehensive income:
Prior service cost (credit)	0	[3]	(2)	[3]
Net loss	(1)	[3]	5	[3]
Weighted-average assumptions used to determine obligations at end of year:
Discount rate	5.00%	[3]	4.25%	[3]
Assumed health care cost trend rates:
Rate assumed for following year	7.75%	[3]	8.50%	[3]
Ultimate rate	5.00%	[3]	5.00%	[3]
Year ultimate rate reached	2020	[3]	2020	[3]
Union Employees | Edison International | Postretirement Benefits Other Than Pensions | Homer City
Amounts recognized in the consolidated balance sheets:
Long-term liabilities			20
Non-Union Employees | Edison International | Postretirement Benefits Other Than Pensions | Homer City
Amounts recognized in the consolidated balance sheets:
Long-term liabilities			$ 11

[1] Includes Homer City.

[2] Represents amount of EME's executive post retirement benefits liability assumed by EIX.

[3] Represents the withdrawal of Homer City from the postretirement benefits plan.