Summary of Significant Accounting Policies (Policies)	6 Months Ended
Summary of Significant Accounting Policies (Policies)	Jun. 30, 2013
Accounting Policies [Abstract]
Organization and Basis of Presentation	Organization and Basis of Presentation Edison International is the parent holding company of Southern California Edison Company ("SCE"). SCE is an investor-owned public utility primarily engaged in the business of supplying electricity to an approximately 50,000 square mile area of southern California. Edison International is also the parent company of nonutility subsidiaries that are engaged in competitive businesses related to the delivery or use of electricity. Such competitive business activities are currently not material to report as a separate business segment. These combined notes to the consolidated financial statements apply to both Edison International and SCE unless otherwise described. Edison International's consolidated financial statements include the accounts of Edison International, SCE and other wholly owned and controlled subsidiaries. References to Edison International refer to the consolidated group of Edison International and its subsidiaries. References to Edison International Parent and Other refer to Edison International Parent and its nonutility subsidiaries. SCE's consolidated financial statements include the accounts of SCE and its wholly owned and controlled subsidiaries. All intercompany transactions have been eliminated from the consolidated financial statements. Edison International's and SCE's significant accounting policies were described in Note 1 of "Notes to Consolidated Financial Statements" included in the 2012 Form 10-K. The same accounting policies are followed for interim reporting purposes, with the exception of accounting principles adopted as of January 1, 2013, discussed below in "—New Accounting Guidance." This quarterly report should be read in conjunction with the financial statements and notes included in the 2012 Form 10-K. Beginning in the fourth quarter of 2012, EME met the definition of a discontinued operation and was classified separately in Edison International's consolidated financial statements. Except as indicated, amounts in the notes to the consolidated financial statements relate to continuing operations of Edison International. See Note 16 for information related to discontinued operations. In the opinion of management, all adjustments, consisting of recurring accruals, have been made that are necessary to fairly state the consolidated financial position, results of operations and cash flows in accordance with accounting principles generally accepted in the United States of America for the periods covered by this quarterly report on Form 10-Q. The results of operations for the three- and six-month periods ended June 30, 2013 are not necessarily indicative of the operating results for the full year. The December 31, 2012 condensed consolidated balance sheet data was derived from audited financial statements, but does not include all disclosures required by accounting principles generally accepted in the United States of America.
Cash Equivalents	Cash is temporarily invested until required for check clearing from the primary disbursement accounts. Cash Equivalents Cash equivalents included investments in money market funds. Generally, the carrying value of cash equivalents equals the fair value, as these investments have original maturities of three months or less.
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, supplies and spare parts.
Greenhouse Gas Emission Allowances	Greenhouse Gas Allowances SCE is allocated greenhouse gas ("GHG") allowances annually which it is then required to submit to quarterly auctions. GHG proceeds from the auction are recorded as a regulatory liability to be refunded to customers. SCE purchases GHG allowances from quarterly auctions or bilateral parties to satisfy its compliance obligations and recovers such costs of GHG from customers. GHG allowances held for use are classified as "Other current assets" on the consolidated balance sheets and are stated at the lower of weighted-average cost or market.
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.
New Accounting Guidance	New Accounting Guidance Accounting Guidance Adopted in 2013 Offsetting Assets and Liabilities In January 2013, the FASB issued accounting standards updates modifying the disclosure requirements about the nature of an entity's rights of offsetting recognized assets and liabilities in the statement of financial position under master netting agreements and similar arrangements associated with derivative instruments, repurchase agreements and securities lending transactions. The guidance requires increased disclosure of the gross and net recognized assets and liabilities, collateral positions and descriptions of setoff rights. Edison International and SCE adopted this guidance effective January 1, 2013. The adoption of this standard did not impact the consolidated income statements, balance sheets or cash flows of Edison International or SCE. Items Reclassified out of Accumulated Other Comprehensive Income In February 2013, the FASB issued an accounting standards update which requires disclosure related to items reclassified out of AOCI. The guidance requires companies to present separately, for each component of other comprehensive income, current period reclassifications and the remainder of the current-period other comprehensive income. In addition, for certain current period reclassifications, an entity is required to disclose the effect of the item reclassified out of AOCI on the respective line item(s) of net income. Edison International and SCE adopted this guidance effective January 1, 2013. See Note 14 for further details. Accounting Guidance Not Yet Adopted In July 2013, the FASB issued an accounting standards update that will require that an unrecognized tax benefit be presented on the balance sheet as a reduction of a deferred tax asset for a net operating loss ("NOL") or tax credit carryforward under certain circumstances. This proposal is effective January 1, 2014 and is not expected to have a material impact on the consolidated financial statements.

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 emission credits or allowances. Such accounting policy has generally been based on an inventory or intangible asset model.

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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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