Variable Interest Entities (Details 2) (USD $) In Millions, unless otherwise specified	6 Months Ended	12 Months Ended
Jun. 30, 2011	Dec. 31, 2010
Variable Interest Entity, Not Primary Beneficiary
Details of projects or entities
Number of projects operated by the subsidiary	three of the four Big 4 projects
Variable Interest Entity, Not Primary Beneficiary \| EMG Domestic Energy Projects
Details of projects or entities
Projects having secured long-term debt to finance the assets constructed and/or acquired by entity	1
Indebtedness of projects accounted for under equity method	65
Indebtedness of projects accounted for under equity method, amount proportionate to ownership interest	16
Variable Interest Entity, Not Primary Beneficiary Holds Significant interest \| EMG Domestic Energy Projects
Details of projects or entities
Equity Interest in Domestic Energy Projects (as a percent)	100.00%
EMG Wind Projects \| Variable Interest Entity, Deconsolidated
Details of projects or entities
Interests in number of wind projects	2	2
Variable Interest Entity, Deconsolidated \| EMG Domestic Energy Projects
Details of projects or entities
Number of projects	5	5
EMG Natural Gas-Fired Projects
Details of projects or entities
Investment	321
Maximum Exposure, Total	321
EMG Renewable energy projects
Details of projects or entities
Investment	229
Maximum Exposure, Total	229

Name:	eix_DisclosureVariableInterestEntityAbstract
Namespace Prefix:	eix
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Number of projects in which the entity has an interest.

The number of variable interests in projects having secured long term debt accounted for under the equity method.

Name:	eix_NumberOfProjectsHavingSecuredLongTermDebtButNoUnilateralControl
Namespace Prefix:	eix
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

This element represents the number of wind projects deconsolidated.

Name:	eix_NumberOfWindProjectsDeconsolidated
Namespace Prefix:	eix
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

The reporting entity's maximum amount of exposure to loss as a result of its variable interests in variable interest entities.

Name:	eix_VariableInterestEntityEntityMaximumLossExposureAmount
Namespace Prefix:	eix
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

This element represents maximum ownership interest in variable interest entity.

Name:	eix_VariableInterestEntityMaximumOwnershipPercentage
Namespace Prefix:	eix
Data Type:	us-types:percentItemType
Balance Type:	na
Period Type:	duration

This element represents carrying amount of investments in variable interest projects accounted for under the equity method.

Name:	eix_VariableInterestEntityNonconsolidatedCarryingAmountAssets
Namespace Prefix:	eix
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

The carrying amount of debt for variable interests in projects accounted for under the equity method.

Name:	eix_VariableInterestEntityNonconsolidatedCarryingAmountDebt
Namespace Prefix:	eix
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

The entity's proportionate share of the debt for the VIE projects accounted for under the equity method, according to the entity's ownership share.

Name:	eix_VariableInterestEntityNonconsolidatedProportionateShareOfDebt
Namespace Prefix:	eix
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Represents the number of projects operated by the subsidiary.

Name:	eix_VariableInterestEntityNumberOfProjectsOperatedBySubsidiary
Namespace Prefix:	eix
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration