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Employee Benefits - Fair Value of Plan Assets (Details) - USD ($) $ in Millions | Dec. 31, 2022 | Dec. 31, 2021 | Dec. 31, 2020
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Fair Value, Measurements, Recurring |  |  |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] |  |  |
Defined Benefit Plan, Plan Assets, Amount |  | $ 79.5 |
Salaried VEBA |  |  |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] |  |  |
Defined Benefit Plan, Plan Assets, Amount | $ 42.4 | 59.2 | $ 60.5
Pension Plans |  |  |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] |  |  |
Defined Benefit Plan, Plan Assets, Amount | 14.9 | 9.8 | $ 8.7
Pension Plans | Equity Funds | Fair Value, Measurements, Recurring |  |  |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] |  |  |
Defined Benefit Plan, Plan Assets, Amount |  | 0.1 |
Pension Plans | Fixed Income Funds | Fair Value, Measurements, Recurring |  |  |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] |  |  |
Defined Benefit Plan, Plan Assets, Amount |  | 0.1 |
Pension Plans | Diversified Investment Funds In Registered Investment Companies | Fair Value, Measurements, Recurring |  |  |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] |  |  |
Defined Benefit Plan, Plan Assets, Amount |  | 9.6 |
Level 1 | Fair Value, Measurements, Recurring |  |  |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] |  |  |
Defined Benefit Plan, Plan Assets, Amount | 67.1 | 69.7 |
Deferred Compensation Plan Assets | 9.8 | 10.5 |
Level 1 | Postretirement Health Coverage | Salaried VEBA | Equity Funds | Fair Value, Measurements, Recurring |  |  |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] |  |  |
Defined Benefit Plan, Plan Assets, Amount | 27.4 | 38.6 |
Level 1 | Postretirement Health Coverage | Salaried VEBA | Fixed Income Funds | Fair Value, Measurements, Recurring |  |  |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] |  |  |
Defined Benefit Plan, Plan Assets, Amount | 15.0 | 20.6 |
Level 1 | Pension Plans | Equity Funds | Fair Value, Measurements, Recurring |  |  |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] |  |  |
Defined Benefit Plan, Plan Assets, Amount | 4.1 |  |
Level 1 | Pension Plans | Fixed Income Funds | Fair Value, Measurements, Recurring |  |  |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] |  |  |
Defined Benefit Plan, Plan Assets, Amount | 2.6 |  |
Level 1 | Pension Plans | Diversified Investment Funds In Registered Investment Companies | Fair Value, Measurements, Recurring |  |  |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] |  |  |
Defined Benefit Plan, Plan Assets, Amount | 8.2 |  |
Fair Value, Inputs, Level 1, 2 and 3 | Fair Value, Measurements, Recurring |  |  |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] |  |  |
Defined Benefit Plan, Plan Assets, Amount | 67.1 | 69.7 |
Deferred Compensation Plan Assets | 9.8 | 10.5 |
Fair Value, Inputs, Level 1, 2 and 3 | Postretirement Health Coverage | Salaried VEBA | Equity Funds | Fair Value, Measurements, Recurring |  |  |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] |  |  |
Defined Benefit Plan, Plan Assets, Amount | 27.4 | 38.6 |
Fair Value, Inputs, Level 1, 2 and 3 | Postretirement Health Coverage | Salaried VEBA | Fixed Income Funds | Fair Value, Measurements, Recurring |  |  |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] |  |  |
Defined Benefit Plan, Plan Assets, Amount | 15.0 | $ 20.6 |
Fair Value, Inputs, Level 1, 2 and 3 | Pension Plans | Equity Funds | Fair Value, Measurements, Recurring |  |  |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] |  |  |
Defined Benefit Plan, Plan Assets, Amount | 4.1 |  |
Fair Value, Inputs, Level 1, 2 and 3 | Pension Plans | Fixed Income Funds | Fair Value, Measurements, Recurring |  |  |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] |  |  |
Defined Benefit Plan, Plan Assets, Amount | 2.6 |  |
Fair Value, Inputs, Level 1, 2 and 3 | Pension Plans | Diversified Investment Funds In Registered Investment Companies | Fair Value, Measurements, Recurring |  |  |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] |  |  |
Defined Benefit Plan, Plan Assets, Amount | $ 8.2 |  |

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