Subsequent Events (Notes)	12 Months Ended
Subsequent Events (Notes)	Dec. 31, 2025
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events Partnership Activity Effective January 1, 2026, the Company acquired the outstanding equity interests of the business of Cobbs Allen Capital Holdings, LLC ("CAC Group") for aggregate consideration paid by the Company at closing consisting of $438.0 million of cash (subject to customary purchase price adjustments) and 23,200,000 shares of the Company's Class A common stock. The purchase consideration also includes a deferred payment of $70.0 million in cash, payable upon the fourth anniversary of the closing date of the transaction. CAC Group may be entitled to receive additional contingent consideration payable in cash based upon the achievement of certain post-closing revenue focused performance measures. The partnership with CAC Group will significantly expand the specialty capabilities of the Company's IAS operating group and strengthen its specialty product lines and data and analytics platform. The Company has not yet completed its evaluation and determination of consideration paid and the identifiable assets and liabilities acquired in accordance with Topic 805. Effective January 2, 2026, the Company acquired the outstanding equity interests of the business of Creisoft, Inc. (“Obie”) for aggregate consideration paid by the Company at closing consisting of $90.0 million of cash (subject to customary purchase price adjustments) and 396,573 shares of the Company's Class A common stock. The purchase consideration also includes deferred payments of $122.5 million in cash, shares of Class A common stock, or a combination of both, payable in three annual installments. Obie may be entitled to receive additional contingent consideration payable in cash, shares of Class A common stock, or a combination of both at the Company's sole option, based upon the achievement of certain post-closing revenue focused performance measures. The partnership with Obie expands access to embedded insurance distribution capabilities for MSI and strengthens its offerings in the rapidly growing real estate investor market. The Company has not yet completed its evaluation and determination of consideration paid and the identifiable assets and liabilities acquired in accordance with Topic 805. Effective January 2, 2026, the Company acquired the outstanding equity interests of the business of Foley Insurance Agency, Inc., doing business as Capstone Group (“Capstone”). The partnership with Capstone expands Baldwin’s regional presence and enhances its ability to deliver comprehensive risk management solutions to a wider client base. The Company has not yet completed its evaluation and determination of consideration paid and the identifiable assets and liabilities acquired in accordance with Topic 805. The relative significance of the aforementioned partnerships in the aggregate, in addition to the issuance of the aggregate 23,951,021 shares of Class A common stock pursuant to such partnerships, may have a significant impact on the Company's financial condition, results of operations and cash flows for the year ended December 31, 2026. The acquisitions of CAC Group and Obie are subsequent events that could give rise to the recognition of deferred tax liabilities through opening balance sheet accounting that will exceed the Company's total deferred tax assets, which could result in the Company releasing a portion or the entirety of its valuation allowance on the total deferred tax assets. Despite this nuance related to partnership activity, the Company continues to expect to remain in a cumulative loss position in 2026. The Company is currently evaluating the impact on the interim consolidated financial statements for 2026. On January 2, 2026, the Company made a payment of $25.0 million to settle a deferred payment to one of its partners. Deferred payments are included in accrued expenses and other current liabilities on the consolidated balance sheets at December 31, 2025. JPM Credit Agreement Amendment On January 2, 2026, the Company entered into Amendment No. 4 to the JPM Credit Agreement (the “January 2026 Refinancing”) to provide for $600.0 million of incremental term loans, increasing the aggregate principal amount of outstanding term loans under the JPM Credit Agreement to approximately $1.604 billion. The Company incurred approximately $12.0 million of debt issuance costs in connection with the January 2026 Refinancing. The incremental term loans are subject to the same terms to which the Term Loans were subject under the JPM Credit Agreement.