Summary of Significant Accounting Policies (Details) (USD $) In Millions, unless otherwise specified	6 Months Ended
Jun. 30, 2011	Dec. 31, 2010
Summary of Significant Accounting Policies
Segment Reporting, Number of Segments	2
Cash Equivalents
Money market funds	$ 743	$ 1,100
Maximum maturity period of cash equivalent investments (in months)	3
Cash reclassified to accounts payable under cash management program	185	197
Inventory
Coal, gas, fuel oil and other raw materials	203	184
Spare parts, materials and supplies	386	384
Total inventory	$ 589	$ 568

This element represents the amount of cash which is reclassified as accounts payable under the cash management program.

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

- Definition

This element represents the maximum maturity period of the investments considered as cash equivalents.

+ Details

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

- Definition

The number of segments in the entity's operations.

+ Details

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

- Definition

Carrying amount as of the balance sheet date of the spare parts, materials and supplies.

+ Details

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

- Details

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

- Details

Name:	us-gaap_CashAndCashEquivalentsAtCarryingValueAbstract
Namespace Prefix:	us-gaap
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Carrying amount as of the balance sheet date of merchandise, goods, commodities, or supplies relating to a source of usable power held for future sale or future use in manufacturing or production process.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 6
-Subparagraph a
-Article 5

+ Details

Name:	us-gaap_EnergyRelatedInventory
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Carrying amount (lower of cost or market) as of the balance sheet date of inventories less all valuation and other allowances. Excludes noncurrent inventory balances (expected to remain on hand past one year or one operating cycle, if longer).

+ Details

Name:	us-gaap_InventoryNet
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Details

Name:	us-gaap_InventoryNetAbstract
Namespace Prefix:	us-gaap
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Investment in short-term money-market instruments (such as commercial paper, banker's acceptances, repurchase agreements, government securities, certificates of deposit, and so forth) which are highly liquid (that is, readily convertible to known amounts of cash) and so near their maturity that they present an insignificant risk of changes in value because of changes in interest rates. Generally, only investments with original maturities of three months or less qualify as cash equivalents by definition. Original maturity means an original maturity to the entity holding the investment. For example, both a three-month US Treasury bill and a three-year Treasury note purchased three months from maturity qualify as cash equivalents. However, a Treasury note purchased three-years ago does not become a cash equivalent when its remaining maturity is three months.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 95
-Paragraph 8, 9

+ Details

Name:	us-gaap_MoneyMarketFundsAtCarryingValue
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant