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Employee Benefits Tables (Details) - USD ($) $ in Millions | 3 Months Ended
--- | ---
Mar. 31, 2019 | Mar. 31, 2018
Other Postretirement Benefits Plan |  |
Defined Benefit Plan Disclosure |  |
Defined Contribution Plan, Cost | $ 3.9 | $ 4.3
Deferred Compensation Arrangement with Individual, Compensation Expense | 0.7 | 0.1
Multiemployer Plan, Contributions by Employer | 1.2 | 1.2
Total other employee benefit plans | 7.5 | 7.1
Postretirement Health Coverage | Salaried VEBA |  |
Defined Benefit Plan Disclosure |  |
Total net periodic postretirement benefit cost relating to Salaried VEBA | 1.7 | 1.5
Salaried VEBA: |  |
Interest cost | 0.8 | 0.7
Expected return on plan assets | (0.6) | (0.7)
Amortization of prior service cost | 1.4 | 1.3
Amortization of net actuarial loss | $ 0.1 | $ 0.2

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