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This element represents, for equity method investments, the minimum equity investment balance required in order for the investment to be disclosed individually.

+ References

No definition available.

+ Details

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Namespace Prefix:	eix_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

This element represents, for equity method investments, the minimum percentage of income before income tax required in order for the investment to be disclosed individually.

+ References

No definition available.

+ Details

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Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Number of projects in which the entity has an interest.

+ References

No definition available.

+ Details

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Namespace Prefix:	eix_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

This element represents maximum ownership interest in variable interest entity.

+ References

No definition available.

+ Details

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Namespace Prefix:	eix_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

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

+ References

No definition available.

+ Details

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Namespace Prefix:	eix_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

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.

+ References

No definition available.

+ Details

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Namespace Prefix:	eix_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Represents the number of projects operated by the subsidiary.

+ References

No definition available.

+ Details

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Namespace Prefix:	eix_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The item represents the difference, if any, between the amount at which an investment accounted for under the equity method of accounting is carried (reported) on the balance sheet and the amount of underlying equity in net assets the reporting Entity has in the investee. A difference can arise between the carrying value of the equity method investment and the value of the Entity's amount of underlying equity in net assets of the investee, for example, from appreciation of certain assets which is not recognized in earnings, but is recognized in other comprehensive income (a separate component of shareholders' equity) by the investee.

+ References

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-Publisher AICPA

-Name Accounting Principles Board Opinion (APB)

-Number 18

-Paragraph 20

-Subparagraph a(3)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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-SubTopic 10

-Section 50

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Period Type:	duration

- Definition

The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

+ References

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-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

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Period Type:	instant

- Definition

This item represents the carrying amount on the entity's balance sheet of its investment in common stock of an equity method investee. This is not an indicator of the fair value of the investment, rather it is the initial cost adjusted for the entity's share of earnings and losses of the investee, adjusted for any distributions (dividends) and other than temporary impairment (OTTI) losses recognized.

+ References

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-SubTopic 10

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-Paragraph 1

-Subparagraph (SX 210.5-02.12)

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Data Type:	xbrli:monetaryItemType
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Period Type:	instant

- Definition

The amount of assets reported by an equity method investment of the entity.

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 235

-SubTopic 10

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-Paragraph 1

-Subparagraph (SX 210.4-08.(g))

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-Publisher SEC

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-URI http://asc.fasb.org/extlink&oid=6957238&loc=d3e14064-108612

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The amount of the cost of sales reported by an equity method investment of the entity.

+ References

No definition available.

+ Details

Name:	us-gaap_EquityMethodInvestmentSummarizedFinancialInformationCostOfSales
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The amount of current assets reported by an equity method investment of the entity.

+ References

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
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Period Type:	instant

- Definition

The amount of current liabilities reported by an equity method investment of the entity.

+ References

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The amount of equity (capital) attributable to the equity method investment of the entity.

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 323

-SubTopic 10

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-URI http://asc.fasb.org/extlink&oid=6881521&loc=d3e23780-122690

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Data Type:	xbrli:monetaryItemType
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- Definition

The amount of liabilities reported by an equity method investment of the entity.

+ References

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Data Type:	xbrli:monetaryItemType
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- Definition

The amount of net income (loss) reported by an equity method investment of the entity.

+ References

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Data Type:	xbrli:monetaryItemType
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Period Type:	duration

- Definition

The amount of noncurrent assets reported by an equity method investment of the entity.

+ References

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- Definition

The amount of noncurrent liabilities reported by an equity method investment of the entity.

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- Definition

The amount of revenue from sale of goods and services reduced by sales returns, allowances, and discounts reported by an equity method investment of the entity.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
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- Definition

Amount of consolidated retained earnings that represent undistributed (not yet received) earnings from 50% or less owned persons accounted for by the equity method (equity method investees).

+ References

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 852

-SubTopic 20

-Section 50

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6462270&loc=d3e57205-112772

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- Definition

The reporting entity's maximum amount of exposure to loss as a result of its involvement with the Variable Interest Entity (VIE).

+ References

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 810

-SubTopic 10

-Section 50

-Paragraph 4

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- Definition

The carrying amount of the assets in the reporting entity's statement of financial position that relate to the reporting entity's variable interest in the Variable Interest Entity (VIE).

+ References

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Variable Interest Entities (Details 2) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
EMG Natural Gas-Fired Projects
Details of projects or entities
Investment	$ 315
Maximum Exposure	315
EMG Wind Projects
Details of projects or entities
Investment	208
Maximum Exposure	208
Variable Interest Entity, Primary Beneficiary \| EMG Wind Projects
Details of projects or entities
Number of projects	0	14
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 and the Sunrise project
Variable Interest Entity, Not Primary Beneficiary \| EMG Domestic Energy Projects
Details of projects or entities
Indebtedness of projects accounted for under equity method	62	116
Indebtedness of projects accounted for under equity method, amount proportionate to ownership interest	16	41
Equity Interests
Revenue	971	1,043	581
Expenses	839	934	506
Net income	132	109	75
Current assets	337	352
Noncurrent assets	2,098	2,437
Total assets	2,435	2,789
Current liabilities	144	227
Noncurrent liabilities	1,230	1,312
Equity	1,061	1,250
Total liabilities and equity	2,435	2,789
Undistributed earnings of equity method investments	19	28
Difference between the carrying value of equity investments and the underlying equity	10
Variable Interest Entity, Not Primary Beneficiary \| EMG Housing Projects
Details of projects or entities
Indebtedness of projects accounted for under equity method	1,200	1,300
Indebtedness of projects accounted for under equity method, amount proportionate to ownership interest	318	451
Variable Interest Entity, Deconsolidated
Equity Interests
Minimum percentage of loss before income tax required in order for the investment to be disclosed individually (as a percent)	5.00%
Minimum equity investment balance required in order for the investment to be disclosed individually.	50
Investment in unconsolidated affiliate	517	550
Variable Interest Entity, Deconsolidated \| San Juan Mesa
Equity Interests
Investment in unconsolidated affiliate	84
Ownership interest in unconsolidated affiliate (as a percent)	75.00%
Variable Interest Entity, Deconsolidated \| Elkhorn Ridge
Equity Interests
Investment in unconsolidated affiliate	81
Ownership interest in unconsolidated affiliate (as a percent)	67.00%
Variable Interest Entity, Deconsolidated \| Sunrise
Equity Interests
Investment in unconsolidated affiliate	173
Ownership interest in unconsolidated affiliate (as a percent)	50.00%
Variable Interest Entity, Deconsolidated \| Sycamore
Equity Interests
Investment in unconsolidated affiliate	34
Ownership interest in unconsolidated affiliate (as a percent)	50.00%
Variable Interest Entity, Deconsolidated \| Kern River
Equity Interests
Investment in unconsolidated affiliate	21
Ownership interest in unconsolidated affiliate (as a percent)	50.00%
Variable Interest Entity, Deconsolidated \| Watson
Equity Interests
Investment in unconsolidated affiliate	$ 42
Ownership interest in unconsolidated affiliate (as a percent)	49.00%
Variable Interest Entity, Deconsolidated \| EMG Domestic Energy Projects
Details of projects or entities
Number of projects	5	5
Maximum \| Variable Interest Entity Not Primary Beneficiary Holds Significant Interest \| EMG Domestic Energy Projects
Details of projects or entities
Equity Interest in Domestic Energy Projects (less than as a percent)	100.00%