Basis of Presentation, Current Accounting Developments and Summary of Significant Accounting Policies Update	9 Months Ended
	Sep. 30, 2025
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation, Current Accounting Developments and Summary of Significant Accounting Policies Update	Basis of Presentation, Current Accounting Developments and Summary of Significant Accounting Policies Update East West Bancorp, Inc. (referred to herein on an unconsolidated basis as “East West” and on a consolidated basis as the “Company,” “we,” “our” or “EWBC”) is a registered bank holding company that offers a full range of banking services to individuals and businesses through its subsidiary bank, East West Bank and its subsidiaries (“East West Bank” or the “Bank”). The unaudited interim Consolidated Financial Statements in this Quarterly Report on Form 10-Q (this “Form 10-Q”) include the accounts of East West, East West Bank and East West’s subsidiaries. All intercompany balances and transactions have been eliminated in consolidation. As of September 30, 2025, East West has one wholly-owned subsidiary that is a statutory business trust (the “Trust”). In accordance with the guidance in Financial Accounting Standards Board Accounting Standards Codification (“ASC”) Topic 810, Consolidation, the Trust has not been consolidated by the Company. The unaudited interim Consolidated Financial Statements are presented in accordance with United States (“U.S.”) Generally Accepted Accounting Principles (“GAAP”), applicable guidelines prescribed by regulatory authorities and general practices in the banking industry. While the unaudited interim Consolidated Financial Statements reflect all adjustments that, in the opinion of management, are necessary for fair presentation, they primarily serve to update the Company’s Annual Report on Form 10-K for the year ended December 31, 2024, filed with the U.S. SEC on February 28, 2025 (the “Company’s 2024 Form 10-K”), and may not include all the information and notes necessary to constitute a complete set of financial statements. Accordingly, they should be read in conjunction with the audited Consolidated Financial Statements and notes thereto included in the Company’s 2024 Form 10-K. The preparation of the Consolidated Financial Statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities as of the date of the Consolidated Financial Statements, income and expenses during the reporting periods, and the related disclosures. Although our estimates consider current conditions and how we expect them to change in the future, it is reasonably possible that actual results could be materially different from those estimates. Hence, the current period’s results of operations are not necessarily indicative of results that may be expected for any future interim period or for the year as a whole. Certain items on the Consolidated Financial Statements and notes for the prior periods have been reclassified to conform to the current presentation. Events subsequent to the Consolidated Balance Sheet date have been evaluated through the date the Consolidated Financial Statements are issued for inclusion in the accompanying Consolidated Financial Statements. New Accounting Pronouncements Adopted The following standards were adopted on January 1, 2025, but they did not have a material impact on the Company’s Consolidated Financial Statements: •Accounting Standards Update (“ASU”) 2023-05, Business Combinations — Joint Venture Formations (Subtopic 805-60): Recognition and Initial Measurement •ASU 2024-02, Codification Improvements — Amendments to Remove References to the Concepts Statements Significant Accounting Policies Update Stock-Based Compensation — The Company recognizes compensation expense related to stock awards over the requisite service period, generally based on the instruments’ grant-date fair value, reduced by expected forfeitures. Effective third quarter 2025, compensation cost related to awards granted to employees who meet certain age plus years-of-service requirements (“retirement-eligible employees”) is accrued over the service period required to earn the award prior to the grant date, in accordance with ASC 718-10-55-108. This change in the timing of recognition for awards that were granted to or are expected to be granted to retirement-eligible employees resulted in $27 million of additional compensation expense during the three months ended September 30, 2025. For more information on the Company’s accounting policies related to stock-based compensation, see Note 1 — Summary of Significant Accounting Policies — Significant Accounting Policies — Stock-Based Compensation to the Consolidated Financial Statements of the Company’s 2024 Form 10-K.