Pension Benefits - Fair Value Plan Assets Measurements (Details) - Pension Plans - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets	$ 0.0	$ 16.3	$ 315.8
Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets		16.2
Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets		0.0
Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets		0.0
Limited Liability Companies and Limited Partnerships
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets		0.1
Limited Liability Companies and Limited Partnerships | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets		0.0
Limited Liability Companies and Limited Partnerships | Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets		0.0
Limited Liability Companies and Limited Partnerships | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets		0.0
Short-term Investments
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets		16.2
Short-term Investments | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets		16.2
Short-term Investments | Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets		0.0
Short-term Investments | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets		0.0
Fair Value, Inputs, Net Asset Value
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets		0.1
Fair Value, Inputs, Net Asset Value | Limited Liability Companies and Limited Partnerships
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets		0.1
Fair Value, Inputs, Net Asset Value | Short-term Investments
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets		$ 0.0