Basis of Presentation and Summary of Significant Accounting Policies Basis of Presentation	9 Months Ended
	Sep. 30, 2025
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation and Summary of Significant Accounting Policies	Note 1 Basis of Presentation and Summary of Significant Accounting Policies BankUnited, Inc. is a national bank holding company with one wholly-owned subsidiary, BankUnited, collectively, the Company. BankUnited, a national banking association headquartered in Miami Lakes, Florida, provides a full range of banking services to individual and corporate customers through banking centers in Florida, the New York metropolitan area and Dallas, Texas. The Bank offers a full suite of commercial lending and deposit products through regional commercial banking offices in Atlanta, Georgia, Morristown, New Jersey and Charlotte, North Carolina and certain commercial lending and deposit products through national platforms. The accompanying unaudited consolidated financial statements have been prepared in accordance with generally accepted accounting principles for interim financial information and the instructions to Form 10-Q and Article 10 of Regulation S-X of the SEC. Accordingly, these financial statements do not include all of the information and footnotes required for a fair presentation of financial position, results of operations and cash flows in conformity with GAAP and should be read in conjunction with the Company’s consolidated financial statements and the notes thereto appearing in BKU’s Annual Report on Form 10-K for the year ended December 31, 2024, filed with the SEC. In the opinion of management, all adjustments, consisting of normal recurring adjustments, considered necessary for a fair presentation have been included. Operating results for the three and nine months ended September 30, 2025 are not necessarily indicative of the results that may be expected in future periods. The Company has a single operating segment and thus a single reportable segment. The Company’s CEO is the CODM. While the CODM monitors the revenue streams and deposit and loan balances of its lines of business, the business lines serve a similar base of primarily commercial clients and provide a comparable range of products and services, all managed through similar processes and platforms. The CODM regularly assesses the performance of its single operating and reporting segment and decides how to allocate resources based on net income as reported in the Company’s consolidated statements of income. The CODM reviews expense information at the same level of detail as that disclosed in the Company's consolidated financial statements. Accounting Estimates In preparing the consolidated financial statements, management is required to make estimates and assumptions that affect the reported amounts of assets, liabilities, revenues, and expenses and disclosures of contingent assets and liabilities. Actual results could differ significantly from these estimates. The most significant estimate impacting the Company's consolidated financial statements is the ACL. Accounting Pronouncements Not Yet Adopted ASU No. 2023-09—Income Taxes (Topic 740): Improvements to Income Tax Disclosures. This ASU requires entities to provide additional disclosures, primarily related to the income tax rate reconciliation and income taxes paid. The guidance also eliminates certain existing disclosure requirements related to uncertain tax positions, among others. This ASU is effective for the Company for fiscal years beginning after December 15, 2024. The ASU stipulates adoption on a prospective basis with the option to apply the standard retrospectively. The Company is planning to adopt this ASU on a retrospective basis when effective for the fiscal year ended December 31, 2025. The adoption of this ASU will not have an impact on the Company's consolidated financial position, results of operations or cash flows. Adoption will lead to revised disclosures about income taxes in the Company's financial statements included within the Company's Annual Report on Form 10-K for the year ending December 31, 2025. ASU No. 2024-03—Income Statement - Reporting Comprehensive Income - Expense Disaggregation Disclosures (Subtopic 220-40): Disaggregation of Income Statement Expenses. This ASU requires additional disclosure in interim and annual periods about specific expense categories in the notes to the financial statements. This ASU is effective for the Company for fiscal years beginning after December 15, 2026, and interim periods within fiscal years beginning after December 15, 2027. The adoption of this ASU is not expected to have an impact on the Company's consolidated financial position, results of operations or cash flows but may lead to additional disclosures about expenses in the Notes to the Consolidated Financial Statements.