Summary of Significant Accounting Policies (Policies)	9 Months Ended
Summary of Significant Accounting Policies (Policies)	Sep. 30, 2020
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") and Edison Energy Group, Inc. ("Edison Energy Group"). SCE is an investor-owned public utility primarily engaged in the business of supplying and delivering electricity to customers in an approximately 50,000 square mile area of southern California. Edison Energy Group is a holding company for Edison Energy, LLC ("Edison Energy") which is engaged in the competitive business of providing energy services to commercial and industrial customers. Edison Energy's 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 competitive subsidiaries and "Edison International Parent" refer to Edison International on a stand-alone basis, not consolidated with its 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 the "Notes to Consolidated Financial Statements" included in Edison International's and SCE's combined Annual Report on Form 10-K for the year ended December 31, 2019 (the "2019 Form 10-K"). This quarterly report should be read in conjunction with the financial statements and notes included in the 2019 Form 10-K. In the opinion of management, all adjustments, consisting only of adjustments of a normal recurring nature, 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 ("GAAP") for the periods covered by this quarterly report on Form 10-Q. The results of operations for the three-month and nine-month periods ended September 30, 2020 are not necessarily indicative of the operating results for the full year.
Cash, Cash Equivalents and Restricted Cash	Cash, Cash Equivalents and Restricted CashCash equivalents include 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.
Allowance for Uncollectible Accounts	Allowance for Uncollectible Accounts The allowance for uncollectible accounts is recorded based on SCE's estimate of expected credit losses and adjusted over the life of the receivables as needed. Since the customer base of SCE is concentrated in Southern California and exposes SCE to a homogeneous set of economic conditions, the allowance is measured on a collective basis on the historical amounts written-off, assessment of customer collectibility and current economic trends, including unemployment rates and any likelihood of recession for the region. At September 30, 2020, this included the estimated impacts of the COVID-19 pandemic.
Earnings Per Share	Earnings Per ShareEdison International computes earnings per common 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.
New Accounting Guidance	New Accounting Guidance Accounting Guidance Adopted In June 2016, the Financial Accounting Standards Board ("FASB") issued an accounting standards update to require the use of the current expected credit loss model to measure impairment of financial assets measured at amortized cost, including trade and other receivables, and the use of an allowance to record estimated credit losses on available-for-sale debt securities. Edison International and SCE adopted this guidance on January 1, 2020 using the prospective adoption approach to available-for-sale debt securities and the modified retrospective approach to all other financial assets. Edison International and SCE hold available-for-sale debt securities in nuclear decommissioning trusts and due to regulatory mechanisms, investment earnings and realized gains and losses have no impact on earnings. Unrealized gains and losses on decommissioning trust funds, including impairments, increase or decrease the trust assets and the related regulatory asset or liability and have no impact on electric utility revenue or decommissioning expense. Upon adoption of this guidance, SCE reviews each fixed income security for impairment on the last day of each month. If the fair value on the last day of the month is less than the amortized cost for that security, SCE impairs the disclosed amortized cost. See Note 10 for further information. The adoption of this guidance did not have a material impact on Edison International's and SCE's other financial assets including receivables. In August 2018, the FASB issued an accounting standards update which aligns the requirement for capitalizing implementation costs incurred in a hosting arrangement that is a service contract with the requirements for capitalizing costs incurred to develop or obtain internal use software. The guidance also clarified presentation requirements for reporting implementation costs in the financial statements. Edison International and SCE adopted the standard on January 1, 2020 using the prospective adoption approach. The adoption of this guidance did not have a material impact on Edison International's and SCE's financial position or result of operations. In March 2020, the FASB issued an accounting standards update to provide optional expedients and exceptions for applying GAAP to contracts, hedging relationships, and other transactions that reference London Inter-Bank Offered Rate ("LIBOR") or another reference rate expected to be discontinued because of reference rate reform. Edison International and SCE have adopted the standard as of April 1, 2020 prospectively. SCE generally does not use hedge accounting for derivative transactions. SCE has a term loan with a variable interest rate based on LIBOR. In addition, both Edison International and SCE have revolving credit facilities with a variable interest rate based on LIBOR. These agreements contain provisions that require an amendment if LIBOR can no longer be used. SCE also has certain preference stocks, for which the distributions will be payable at a floating rate referenced to LIBOR from 2022. As of September 30, 2020, both Edison International and SCE have not utilized any of the expedients and therefore there is no impact on adoption of the guidance, however, if contract amendments are made where LIBOR is no longer valid, both Edison International and SCE expect to utilize the expedients through the allowed period of December 31, 2022. In August 2018, the FASB issued an accounting standards update to remove, modify and add certain disclosure requirements related to employer-sponsored defined benefit pension or other postretirement plans. The guidance removes disclosure requirements that are no longer considered cost beneficial, clarifies certain specific disclosure requirements and adds disclosure requirements identified as relevant. The modifications only affect annual period disclosures and must be applied on a retrospective basis to all periods presented. Edison International and SCE have adopted this guidance for the year ending December 31, 2020. The adoption of this guidance will not materially affect the annual disclosures related to employer-sponsored defined benefit pension or other postretirement plans. Accounting Guidance Not Yet Adopted In August 2020, the FASB issued an accounting standards update to simplify the accounting for certain financial instruments with characteristics of liabilities and equity. The amendments in this update affect entities that issue convertible instruments indexed to or potentially settled in an entity's own equity. This guidance also simplifies an entity's application of the derivatives scope exception for contracts in its own equity and amends certain aspects of the EPS guidance. The guidance is effective January 1, 2022 with early adoption permitted after January 1, 2021. Edison International and SCE are currently evaluating the impact of the guidance.