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Employee Benefits - Benefit Obligations and Funded Status of Pension Plans, OPEB and Salaried VEBAs (Details) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2024 | Dec. 31, 2023 | Dec. 31, 2022
Salaried VEBA |  |  |
Change in benefit obligation: |  |  |
Obligation at beginning of year | $ 46.9 | $ 58.9 |
Interest cost | 2.2 | 2.9 |
Prior service cost (credit) |  | (8.8) |
Actuarial (gain) loss | (1.4) | 0.4 |
Benefits paid | (4.8) | (6.5) |
Obligation at end of year | 42.9 | 46.9 | $ 58.9
Change in plan assets: |  |  |
Fair market value of plan assets at beginning of year | 43.1 | 42.4 |
Actual return on assets | 3.9 | 6.1 |
Company contributions | 0.7 | 1.1 |
Benefits paid | (4.8) | (6.5) |
Fair market value of plan assets at end of year | 42.9 | 43.1 | 42.4
Net funded status |  | (3.8) |
Cumulative gain (loss) recognized in Accumulated other comprehensive income: |  |  |
Accumulated net actuarial gain | 8.2 | 5.2 |
Prior service cost | (14.3) | (16.0) |
Total | (6.1) | (10.8) |
Pension Plans |  |  |
Change in benefit obligation: |  |  |
Obligation at beginning of year | 30.5 | 18.8 |
Foreign currency translation adjustment | (0.5) | 0.2 |
Service cost | 3.6 | 3.8 | 5.8
Interest cost | 1.6 | 1.3 | 0.6
Prior service cost (credit) | 2.2 | 6.6 |
Actuarial (gain) loss | (1.6) | 0.2 |
Plan participants contributions | 0.1 | 0.1 |
Benefits paid | (0.7) | (0.5) |
Settlements | (4.5) |  |
Obligation at end of year | 30.7 | 30.5 | 18.8
Change in plan assets: |  |  |
Fair market value of plan assets at beginning of year | 20.5 | 14.9 |
Foreign currency translation adjustment | 0.3 | 0.2 |
Actual return on assets | 0.9 | 1.4 |
Plan participants contributions | 0.1 | 0.1 |
Company contributions | 5.9 | 4.4 |
Benefits paid | (0.7) | (0.5) |
Settlements | (4.5) |  |
Fair market value of plan assets at end of year | 22.5 | 20.5 | 14.9
Net funded status | (8.2) | (10.0) |
Cumulative gain (loss) recognized in Accumulated other comprehensive income: |  |  |
Accumulated net actuarial gain | 4.2 | 1.3 |
Prior service cost | (7.6) | (6.1) |
Total | (3.4) | (4.8) |
Other Postretirement Benefits Plan |  |  |
Change in benefit obligation: |  |  |
Obligation at beginning of year | 68.8 | 66.4 |
Service cost | 1.1 | 1.1 | 1.6
Interest cost | 3.3 | 3.4 | 2.2
Actuarial (gain) loss | (6.8) | (0.7) |
Plan participants contributions | 0.2 | 0.1 |
Benefits paid | (1.9) | (1.5) |
Obligation at end of year | 64.7 | 68.8 | $ 66.4
Change in plan assets: |  |  |
Plan participants contributions | 0.2 | 0.1 |
Company contributions | 1.7 | 1.4 |
Benefits paid | (1.9) | (1.5) |
Net funded status | (64.7) | (68.8) |
Cumulative gain (loss) recognized in Accumulated other comprehensive income: |  |  |
Accumulated net actuarial gain | 23.1 | 17.4 |
Total | $ 23.1 | $ 17.4 |

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