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Investments - Net Investment Gains (Losses) By Transaction Type (Details) - USD ($) $ in Millions | 12 Months Ended
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Dec. 31, 2024 | Dec. 31, 2023 | Dec. 31, 2022
Investments, Debt and Equity Securities [Abstract] |  |  |  |
Credit loss impairments | $ 0.3 | $ (0.4) | $ (3.1) |
Intent-to-sell impairments | (0.2) | (6.7) | (7.6) |
Total impairments | 0.1 | (7.1) | (10.7) |
Sales and other, net | (24.3) | (25.0) | (17.8) |
Change in fair value - equity securities | 7.4 | 7.9 | (33.2) |
Change in fair value and losses realized on settlements - derivatives | (0.5) | 0.2 | 5.2 |
Net investment losses | $ (17.3) | $ (24.0) | $ (56.5) | [1]
[1] | Recast for the adoption of ASU 2018-12.

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- Definition Other than Temporary Impairment Loss, Investments, Portion Recognized In Earnings, Change In Intent + References No definition available. + Details
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- Definition Amount of gain (loss) from the increase (decrease) in fair value of derivative and nonderivative instruments designated as fair value hedging instruments recognized in the income statement. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 815 -SubTopic 25 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (a)(1) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480238/815-25-50-1 + Details
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