Summary of Significant Accounting Policies (Policies)	9 Months Ended
Sep. 30, 2012
Accounting Policies [Abstract]
Cash Equivalents	Cash Equivalents Cash equivalents included investments in money market funds totaling $933 million and $1.3 billion at September 30, 2012 and December 31, 2011, respectively. Generally, the carrying value of cash equivalents equals the fair value, as these investments have original maturities of three months or less. Edison International temporarily invests the ending daily cash balance in its primary disbursement accounts until required for check clearing. Edison International reclassified $234 million and $220 million of checks issued, but not yet paid by the financial institution, from cash to accounts payable at September 30, 2012 and December 31, 2011, respectively.
Restricted Cash and Cash Equivalents	Restricted Cash and Cash Equivalents, and Restricted Deposits Restricted cash and cash equivalents at September 30, 2012 and December 31, 2011 included $97 million received from a wind project financing that was held in escrow at those dates. At September 30, 2012, restricted deposits included $48 million to support outstanding letters of credit issued under EME's letter of credit facilities.
Inventory	Inventory Inventory is stated at the lower of cost or market, cost being determined by the weighted-average cost method for fuel, and the average cost method for materials and supplies.
Revenue Recognition	Revenue Recognition Electric Utility Revenue Operating revenue is recognized when electricity is delivered and includes amounts for services rendered but unbilled at the end of each reporting period. During the first nine months of 2012, pending the outcome of the 2012 GRC, SCE recognized GRC-related revenue based on the 2011 authorized revenue requirement included in customer rates. A GRC memorandum account has been established for SCE, which will make the 2012 revenue requirement ultimately adopted by the CPUC effective as of January 1, 2012.
Earnings Per Share	Earnings Per Share Edison International computes earnings per share ("EPS") using the two-class method, which is an earnings allocation formula that determines EPS for each class of common stock and participating security. Edison International's participating securities are stock-based compensation awards payable in common shares, including stock options, performance shares and restricted stock units, which earn dividend equivalents on an equal basis with common shares. Stock options awarded during the period 2003 through 2006 received dividend equivalents.

Summary of Significant Accounting Policies (Policies)

9 Months Ended

Sep. 30, 2012

Cash equivalents included investments in money market funds totaling $933 million and $1.3 billion at September 30, 2012 and December 31, 2011, respectively. Generally, the carrying value of cash equivalents equals the fair value, as these investments have original maturities of three months or less.

Edison International temporarily invests the ending daily cash balance in its primary disbursement accounts until required for check clearing. Edison International reclassified $234 million and $220 million of checks issued, but not yet paid by the financial institution, from cash to accounts payable at September 30, 2012 and December 31, 2011, respectively.

Restricted Cash and Cash Equivalents

Restricted Cash and Cash Equivalents, and Restricted Deposits

Restricted cash and cash equivalents at September 30, 2012 and December 31, 2011 included $97 million received from a wind project financing that was held in escrow at those dates. At September 30, 2012, restricted deposits included $48 million to support outstanding letters of credit issued under EME's letter of credit facilities.

Inventory

Inventory is stated at the lower of cost or market, cost being determined by the weighted-average cost method for fuel, and the average cost method for materials and supplies.

Revenue Recognition

Electric Utility Revenue

Operating revenue is recognized when electricity is delivered and includes amounts for services rendered but unbilled at the end of each reporting period. During the first nine months of 2012, pending the outcome of the 2012 GRC, SCE recognized GRC-related revenue based on the 2011 authorized revenue requirement included in customer rates. A GRC memorandum account has been established for SCE, which will make the 2012 revenue requirement ultimately adopted by the CPUC effective as of January 1, 2012.

Earnings Per Share

Edison International computes earnings per share ("EPS") using the two-class method, which is an earnings allocation formula that determines EPS for each class of common stock and participating security. Edison International's participating securities are stock-based compensation awards payable in common shares, including stock options, performance shares and restricted stock units, which earn dividend equivalents on an equal basis with common shares. Stock options awarded during the period 2003 through 2006 received dividend equivalents.

- Definition

Disclosure of accounting policy for cash and cash equivalents with respect to unrestricted balances.

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- Definition

Disclosure of accounting policy for computing basic and diluted earnings or loss per share for each class of common stock and participating security. Addresses all significant policy factors, including any antidilutive items that have been excluded from the computation and takes into account stock dividends, splits and reverse splits that occur after the balance sheet date of the latest reporting period but before the issuance of the financial statements.

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- Definition

Disclosure of accounting policy for major classes of inventories, bases of stating inventories (for example, lower of cost or market), methods by which amounts are added and removed from inventory classes (for example, FIFO, LIFO, or average cost), loss recognition on impairment of inventories, and situations in which inventories are stated above cost. If inventory is carried at cost, this disclosure includes the nature of the cost elements included in inventory.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef

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-Publisher AICPA

-Name Accounting Research Bulletin (ARB)

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-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.

Reference 5: http://www.xbrl.org/2003/role/presentationRef

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-Publisher AICPA

-Name Statement of Position (SOP)

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-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.

Reference 7: http://www.xbrl.org/2003/role/presentationRef

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-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.

Reference 11: http://www.xbrl.org/2003/role/presentationRef

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+ Details

- Definition

Disclosure of accounting policy for revenue recognition. If the entity has different policies for different types of revenue transactions, the policy for each material type of transaction is generally disclosed. If a sales transaction has multiple element arrangements (for example, delivery of multiple products, services or the rights to use assets) the disclosure may indicate the accounting policy for each unit of accounting as well as how units of accounting are determined and valued. The disclosure may encompass important judgment as to appropriateness of principles related to recognition of revenue. The disclosure also may indicate the entity's treatment of any unearned or deferred revenue that arises from the transaction.

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