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v3.23.3

Investments - Fair Value and Gross Unrealized Losses (Details) $ in Millions | Sep. 30, 2023 USD ($) | Sep. 30, 2023 security | Sep. 30, 2023 | Sep. 30, 2023 position | Dec. 31, 2022 USD ($) | Dec. 31, 2022 security | Dec. 31, 2022 | Dec. 31, 2022 position
--- | --- | --- | --- | --- | --- | --- | --- | ---
Fixed maturity securities, Gross Unrealized Losses |  |  |  |  |  |  |  |
Number of positions with a gross unrealized loss, 12 Months or Less (security) | security |  | 669 |  |  |  | 2,515 |  |
Number of positions with a gross unrealized loss, more than 12 months (security) |  | 2,474 |  | 2,474 |  | 587 |  | 587
Number of positions with a gross unrealized loss, Total (security) | security |  | 3,143 |  |  |  | 3,102 |  |
Fair value as a percentage of total fixed maturities and equity securities fair value, 12 Months or Less (percent) |  |  | 18.20% |  |  |  | 68.20% |
Fair value as a percentage of total fixed maturities and equity securities fair value, more than 12 months (percent) |  |  | 68.20% |  |  |  | 14.20% |
Fair value as a percentage of total fixed maturities and equity securities fair value, Total (percent) |  |  | 86.40% |  |  |  | 82.40% |
Total |  |  |  |  |  |  |  |
Fixed maturity securities, Fair Value |  |  |  |  |  |  |  |
Fixed maturity securities, Fair Value, 12 Months or Less | $ 901.5 |  |  |  | $ 3,533.7 |  |  |
Fixed maturity securities, Fair Value, More than 12 Months | 3,384.9 |  |  |  | 734.2 |  |  |
Fixed maturity securities, Fair Value, Total | 4,286.4 |  |  |  | 4,267.9 |  |  |
Fixed maturity securities, Gross Unrealized Losses |  |  |  |  |  |  |  |
Fixed maturity securities, Gross Unrealized Losses, 12 Months or Less | 44.0 |  |  |  | 461.8 |  |  |
Fixed maturity securities, Gross Unrealized Losses, More than 12 Months | 658.8 |  |  |  | 145.1 |  |  |
Fixed maturity securities, Gross Unrealized Losses, Total | 702.8 |  |  |  | 606.9 |  |  |
Mortgage-backed securities |  |  |  |  |  |  |  |
Fixed maturity securities, Fair Value |  |  |  |  |  |  |  |
Fixed maturity securities, Fair Value, 12 Months or Less | 137.1 |  |  |  | 458.3 |  |  |
Fixed maturity securities, Fair Value, More than 12 Months | 438.2 |  |  |  | 52.6 |  |  |
Fixed maturity securities, Fair Value, Total | 575.3 |  |  |  | 510.9 |  |  |
Fixed maturity securities, Gross Unrealized Losses |  |  |  |  |  |  |  |
Fixed maturity securities, Gross Unrealized Losses, 12 Months or Less | 5.3 |  |  |  | 54.4 |  |  |
Fixed maturity securities, Gross Unrealized Losses, More than 12 Months | 91.9 |  |  |  | 14.7 |  |  |
Fixed maturity securities, Gross Unrealized Losses, Total | 97.2 |  |  |  | 69.1 |  |  |
Other |  |  |  |  |  |  |  |
Fixed maturity securities, Fair Value |  |  |  |  |  |  |  |
Fixed maturity securities, Fair Value, 12 Months or Less | 91.9 |  |  |  | 242.7 |  |  |
Fixed maturity securities, Fair Value, More than 12 Months | 268.5 |  |  |  | 65.8 |  |  |
Fixed maturity securities, Fair Value, Total | 360.4 |  |  |  | 308.5 |  |  |
Fixed maturity securities, Gross Unrealized Losses |  |  |  |  |  |  |  |
Fixed maturity securities, Gross Unrealized Losses, 12 Months or Less | 3.7 |  |  |  | 34.1 |  |  |
Fixed maturity securities, Gross Unrealized Losses, More than 12 Months | 81.3 |  |  |  | 33.7 |  |  |
Fixed maturity securities, Gross Unrealized Losses, Total | 85.0 |  |  |  | 67.8 |  |  |
Municipal bonds |  |  |  |  |  |  |  |
Fixed maturity securities, Fair Value |  |  |  |  |  |  |  |
Fixed maturity securities, Fair Value, 12 Months or Less | 331.1 |  |  |  | 911.6 |  |  |
Fixed maturity securities, Fair Value, More than 12 Months | 729.9 |  |  |  | 42.2 |  |  |
Fixed maturity securities, Fair Value, Total | 1,061.0 |  |  |  | 953.8 |  |  |
Fixed maturity securities, Gross Unrealized Losses |  |  |  |  |  |  |  |
Fixed maturity securities, Gross Unrealized Losses, 12 Months or Less | 13.7 |  |  |  | 113.7 |  |  |
Fixed maturity securities, Gross Unrealized Losses, More than 12 Months | 146.1 |  |  |  | 14.4 |  |  |
Fixed maturity securities, Gross Unrealized Losses, Total | 159.8 |  |  |  | 128.1 |  |  |
Foreign government bonds |  |  |  |  |  |  |  |
Fixed maturity securities, Fair Value |  |  |  |  |  |  |  |
Fixed maturity securities, Fair Value, 12 Months or Less | 1.4 |  |  |  | 32.7 |  |  |
Fixed maturity securities, Fair Value, More than 12 Months | 23.1 |  |  |  | 0.4 |  |  |
Fixed maturity securities, Fair Value, Total | 24.5 |  |  |  | 33.1 |  |  |
Fixed maturity securities, Gross Unrealized Losses |  |  |  |  |  |  |  |
Fixed maturity securities, Gross Unrealized Losses, 12 Months or Less | 0.1 |  |  |  | 1.4 |  |  |
Fixed maturity securities, Gross Unrealized Losses, More than 12 Months | 1.5 |  |  |  | 0.2 |  |  |
Fixed maturity securities, Gross Unrealized Losses, Total | 1.6 |  |  |  | 1.6 |  |  |
Corporate bonds |  |  |  |  |  |  |  |
Fixed maturity securities, Fair Value |  |  |  |  |  |  |  |
Fixed maturity securities, Fair Value, 12 Months or Less | 204.9 |  |  |  | 1,345.0 |  |  |
Fixed maturity securities, Fair Value, More than 12 Months | 1,120.8 |  |  |  | 148.9 |  |  |
Fixed maturity securities, Fair Value, Total | 1,325.7 |  |  |  | 1,493.9 |  |  |
Fixed maturity securities, Gross Unrealized Losses |  |  |  |  |  |  |  |
Fixed maturity securities, Gross Unrealized Losses, 12 Months or Less | 18.6 |  |  |  | 221.1 |  |  |
Fixed maturity securities, Gross Unrealized Losses, More than 12 Months | 286.0 |  |  |  | 51.1 |  |  |
Fixed maturity securities, Gross Unrealized Losses, Total | 304.6 |  |  |  | 272.2 |  |  |
Other asset-backed securities |  |  |  |  |  |  |  |
Fixed maturity securities, Fair Value |  |  |  |  |  |  |  |
Fixed maturity securities, Fair Value, 12 Months or Less | 135.1 |  |  |  | 543.4 |  |  |
Fixed maturity securities, Fair Value, More than 12 Months | 804.4 |  |  |  | 424.3 |  |  |
Fixed maturity securities, Fair Value, Total | 939.5 |  |  |  | 967.7 |  |  |
Fixed maturity securities, Gross Unrealized Losses |  |  |  |  |  |  |  |
Fixed maturity securities, Gross Unrealized Losses, 12 Months or Less | 2.6 |  |  |  | 37.1 |  |  |
Fixed maturity securities, Gross Unrealized Losses, More than 12 Months | 52.0 |  |  |  | 31.0 |  |  |
Fixed maturity securities, Gross Unrealized Losses, Total | $ 54.6 |  |  |  | $ 68.1 |  |  |

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