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Investments - Schedule of Changes in Other Investments (Details) - USD ($) $ in Millions | 3 Months Ended | 6 Months Ended
--- | --- | ---
Jun. 30, 2025 | Jun. 30, 2024 | Jun. 30, 2025 | Jun. 30, 2024
Other Investments [Roll Forward] |  |  |  |
Balance, beginning of period | $ 526.3 | $ 522.9 | $ 539.0 | $ 480.9
Purchases and commitments funded | 40.8 | 17.8 | 48.9 | 64.6
Sales and distributions | (17.0) | (17.7) | (41.8) | (26.7)
Net realized and unrealized gains | 16.0 | 7.3 | 20.0 | 11.5
Balance, end of period | 566.1 | 530.3 | 566.1 | 530.3
Equity Securities Without Readily Determinable Fair Value [Roll Forward] |  |  |  |
Balance, beginning of period | 50.4 | 50.4 | 50.4 | 50.4
Purchases and commitments funded | 0.0 | 0.0 | 0.0 | 0.0
Sales and distributions | 0.0 | 0.0 | 0.0 | 0.0
Net realized and unrealized gains | 0.0 | 0.0 | 0.0 | 0.0
Balance, end of period | 50.4 | 50.4 | 50.4 | 50.4
Fair Value Measured at NAV |  |  |  |
Other Investments [Roll Forward] |  |  |  |
Balance, beginning of period | 475.9 | 472.5 | 488.6 | 430.5
Purchases and commitments funded | 40.8 | 17.8 | 48.9 | 64.6
Sales and distributions | (17.0) | (17.7) | (41.8) | (26.7)
Net realized and unrealized gains | 16.0 | 7.3 | 20.0 | 11.5
Balance, end of period | $ 515.7 | $ 479.9 | $ 515.7 | $ 479.9

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