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Other Investments - Schedule of Changes in Other Investments (Details) - USD ($) $ in Millions | 3 Months Ended | 6 Months Ended
--- | --- | ---
Jun. 30, 2022 | Jun. 30, 2021 | Jun. 30, 2022 | Jun. 30, 2021
Other Investments [Roll Forward] |  |  |  |
Balance, beginning of period | $ 394.1 | $ 292.7 | $ 375.2 | $ 257.2
Other realized and unrealized gains (losses) | (13.7) | 20.4 | 1.7 | 50.2
Purchases and commitments | 12.1 | 8.8 | 27.1 | 26.9
Sales and distributions | (7.8) | (9.8) | (19.3) | (22.2)
Balance, end of period | 384.7 | 312.1 | 384.7 | 312.1
Equity Securities Without Readily Determinable Fair Value [Roll Forward] |  |  |  |
Balance, beginning of period | 50.4 | 13.8 | 50.4 | 13.8
Net realized and unrealized gains | 0.0 | 0.0 | 0.0 | 0.0
Purchases and commitments | 0.0 | 0.0 | 0.0 | 0.0
Sales and distributions | 0.0 | 0.0 | 0.0 | 0.0
Balance, end of period | 50.4 | 13.8 | 50.4 | 13.8
Fair Value Measured at NAV |  |  |  |
Other Investments [Roll Forward] |  |  |  |
Balance, beginning of period | 343.7 | 278.9 | 324.8 | 243.4
Other realized and unrealized gains (losses) | (13.7) | 20.4 | 1.7 | 50.2
Purchases and commitments | 12.1 | 8.8 | 27.1 | 26.9
Sales and distributions | (7.8) | (9.8) | (19.3) | (22.2)
Balance, end of period | $ 334.3 | $ 298.3 | $ 334.3 | $ 298.3

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