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Pension and Other Postretirement Benefits - Fair Value Hierarchy (Details) - Pension - USD ($) $ in Millions | Dec. 31, 2024 | Dec. 31, 2023 | Dec. 31, 2022
--- | --- | --- | ---
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of assets | $ 245.1 | $ 256.8 | $ 216.6
Level 1 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of assets | 32.6 | 31.4 |
Level 2 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of assets | 0.6 | 0.6 |
Level 3 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of assets | 0.0 | 0.0 |
Assets measured at NAV |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of assets | 211.9 | 224.8 |
Cash |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of assets | 3.5 | 5.0 |
Cash | Level 1 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of assets | 0.7 | 0.4 |
Cash | Level 2 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of assets | 0.0 | 0.0 |
Cash | Level 3 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of assets | 0.0 | 0.0 |
Cash | Assets measured at NAV |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of assets | 2.8 | 4.6 |
Global equity |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of assets | 128.1 | 119.7 |
Global equity | Level 1 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of assets | 20.0 | 19.7 |
Global equity | Level 2 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of assets | 0.0 | 0.0 |
Global equity | Level 3 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of assets | 0.0 | 0.0 |
Global equity | Assets measured at NAV |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of assets | 108.1 | 100.0 |
Diversified credit |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of assets | 47.1 | 45.9 |
Diversified credit | Level 1 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of assets | 11.8 | 11.2 |
Diversified credit | Level 2 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of assets | 0.0 | 0.0 |
Diversified credit | Level 3 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of assets | 0.0 | 0.0 |
Diversified credit | Assets measured at NAV |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of assets | 35.3 | 34.7 |
Real assets |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of assets | 23.1 | 22.8 |
Real assets | Level 1 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of assets | 0.0 | 0.0 |
Real assets | Level 2 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of assets | 0.0 |  |
Real assets | Level 3 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of assets | 0.0 | 0.0 |
Real assets | Assets measured at NAV |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of assets | 23.1 | 22.8 |
Liability hedging assets |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of assets | 42.6 | 62.7 |
Liability hedging assets | Level 1 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of assets | 0.0 | 0.0 |
Liability hedging assets | Level 2 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of assets | 0.0 | 0.0 |
Liability hedging assets | Level 3 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of assets | 0.0 | 0.0 |
Liability hedging assets | Assets measured at NAV |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of assets | 42.6 | 62.7 |
Other |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of assets | 0.7 | 0.7 |
Other | Level 1 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of assets | 0.1 | 0.1 |
Other | Level 2 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of assets | 0.6 | 0.6 |
Other | Level 3 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of assets | 0.0 | 0.0 |
Other | Assets measured at NAV |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of assets | $ 0.0 | $ 0.0 |

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