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Retirement Plans and Other Postretirement Benefits - Contributions and Plan Assets (Details) - Pension Plan - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2022
Dec. 31, 2021
Dec. 31, 2020
Dec. 31, 2019
Defined Benefit Plan Disclosure [Line Items]        
Contributions to employees' accounts $ 0.0 $ 0.0 $ 0.0  
Total assets at the end of the year 13.6 19.8 22.0 $ 23.2
Qualified Plan | 401(k) plan        
Defined Benefit Plan Disclosure [Line Items]        
Contributions to employees' accounts 9.4 8.2 8.2  
Total assets at the end of the year 207.1 246.9 228.4  
Nonqualified Plan        
Defined Benefit Plan Disclosure [Line Items]        
Total assets at the end of the year 0.0 0.0 0.0  
Contributions to employees' accounts $ 0.1 $ 0.1 $ 0.1