Pension Benefits - Fair Value Plan Assets Measurements (Details) - Pension Plans, Defined Benefit - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets	$ 315.8	$ 391.7	$ 405.4
Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets	268.1	320.3
Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets	45.9	63.0
Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets	0.0	0.0
United States Government and Government Agencies and Authorities
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets	40.1	54.6
United States Government and Government Agencies and Authorities | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets	40.1	54.6
United States Government and Government Agencies and Authorities | Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets	0.0	0.0
United States Government and Government Agencies and Authorities | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets	0.0	0.0
States and Political Subdivisions
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets	0.1	0.1
States and Political Subdivisions | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets	0.0	0.0
States and Political Subdivisions | Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets	0.1	0.1
States and Political Subdivisions | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets	0.0	0.0
Corporate Bonds and Notes
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets	45.4	62.3
Corporate Bonds and Notes | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets	0.0	0.0
Corporate Bonds and Notes | Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets	45.4	62.3
Corporate Bonds and Notes | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets	0.0	0.0
Bond Exchange Traded Funds
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets	111.1	125.0
Bond Exchange Traded Funds | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets	111.1	125.0
Bond Exchange Traded Funds | Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets	0.0	0.0
Bond Exchange Traded Funds | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets	0.0	0.0
Limited Liability Companies and Limited Partnerships
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets	1.8	8.4
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	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	0.0
Limited Liability Companies and Limited Partnerships | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets	0.0	0.0
Short-term Investments
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets	116.1	140.2
Short-term Investments | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets	116.1	140.2
Short-term Investments | Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets	0.0	0.0
Short-term Investments | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets	0.0	0.0
Receivables and Other
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets	0.8	0.5
Receivables and Other | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets	0.8	0.5
Receivables and Other | Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets	0.0	0.0
Receivables and Other | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets	0.0	0.0
Foreign Governments
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets	0.4	0.6
Foreign Governments | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets	0.0	0.0
Foreign Governments | Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets	0.4	0.6
Foreign Governments | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets	0.0	0.0
Measured at Net Asset Value
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets	1.8	8.4
Measured at Net Asset Value | United States Government and Government Agencies and Authorities
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets	0.0	0.0
Measured at Net Asset Value | States and Political Subdivisions
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets	0.0	0.0
Measured at Net Asset Value | Corporate Bonds and Notes
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets	0.0	0.0
Measured at Net Asset Value | Bond Exchange Traded Funds
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets	0.0	0.0
Measured at Net Asset Value | Limited Liability Companies and Limited Partnerships
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets	1.8	8.4
Measured at Net Asset Value | Short-term Investments
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets	0.0	0.0
Measured at Net Asset Value | Receivables and Other
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets	0.0	0.0
Measured at Net Asset Value | Foreign Governments
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets	$ 0.0	$ 0.0