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Other Investments - Schedule of Changes in Other Investments (Details) - USD ($) $ in Millions | 3 Months Ended
--- | ---
Mar. 31, 2023 | Mar. 31, 2022
Other Investments [Roll Forward] |  |
Balance, beginning of period | $ 421.6 | $ 375.2
Purchases and commitments | 9.8 | 15.1
Sales and distributions | (11.5) | (11.5)
Net realized and unrealized gains | 6.1 | 15.3
Balance, end of period | 426.0 | 394.1
Without Readily Determinable Fair Values |  |
Balance, beginning of period | 50.4 | 50.4
Purchases and commitments | 0.0 | 0.0
Sales and distributions | 0.0 | 0.0
Net realized and unrealized gains | 0.0 | 0.0
Balance, end of period | 50.4 | 50.4
Fair Value Measured at NAV |  |
Other Investments [Roll Forward] |  |
Balance, beginning of period | 371.2 | 324.8
Purchases and commitments | 9.8 | 15.1
Sales and distributions | (11.5) | (11.5)
Net realized and unrealized gains | 6.1 | 15.3
Balance, end of period | $ 375.6 | $ 343.7

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