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v3.23.2

Marketable Securities Held in Trusts - Continuous Loss Position (Details) - USD ($) $ in Millions | 3 Months Ended | 6 Months Ended |
--- | --- | --- | ---
Jun. 30, 2023 | Jun. 30, 2022 | Jun. 30, 2023 | Jun. 30, 2022 | Dec. 31, 2022
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss |  |  |  |  |
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value | $ 200.2 |  | $ 200.2 |  | $ 135.5
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss | (17.7) |  | (17.7) |  | (15.8)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months | 256.8 |  | 256.8 |  | 475.2
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss | 3.8 |  | 3.8 |  | 12.9
Corporate debt securities |  |  |  |  |
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss |  |  |  |  |
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value | 114.9 |  | 114.9 |  | 72.8
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss | (12.0) |  | (12.0) |  | (10.6)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months | 60.6 |  | 60.6 |  | 105.6
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss | 1.4 |  | 1.4 |  | 6.5
Municipal bonds |  |  |  |  |
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss |  |  |  |  |
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value | 85.3 |  | 85.3 |  | 61.9
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss | (5.7) |  | (5.7) |  | (5.1)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months | 84.0 |  | 84.0 |  | 104.7
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss | 1.2 |  | 1.2 |  | 2.9
U.S. government bonds |  |  |  |  |
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss |  |  |  |  |
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value | 0.0 |  | 0.0 |  | 0.8
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss | 0.0 |  | 0.0 |  | (0.1)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months | 112.2 |  | 112.2 |  | 264.9
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss | 1.2 |  | 1.2 |  | $ 3.5
Debt securities |  |  |  |  |
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss |  |  |  |  |
Debt Securities, Available-for-sale, Realized Loss | $ 1.8 | $ 24.9 | $ 15.2 | $ 25.9 |

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