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v3.25.1

EMPLOYEE BENEFITS-COSTS AND CONTRIBUTIONS (Details) - USD ($) $ in Millions | 3 Months Ended |
--- | --- | ---
Mar. 31, 2025 | Mar. 31, 2024 | Dec. 31, 2024
Components of net periodic benefit cost (credit) |  |  |
Contributions and payments related to pension and OPEB plans | $ 3.9 | $ 4.0 |
Total regulatory assets | 3,367.8 |  | $ 3,378.7
Pension Benefits |  |  |
Components of net periodic benefit cost (credit) |  |  |
Service cost | 5.7 | 6.7 |
Interest cost | 30.3 | 29.5 |
Expected return on plan assets | (44.1) | (45.8) |
Amortization of net actuarial (gain) loss | 13.6 | 14.4 |
Net periodic benefit (credit) cost | 5.5 | 4.8 |
Contributions and payments related to pension and OPEB plans | 3.5 |  |
Estimated future employer contributions for the remainder of the year | 8.6 |  |
Pension Benefits | Pension and Other Postretirement Plans Cost |  |  |
Components of net periodic benefit cost (credit) |  |  |
Total regulatory assets | 19.5 |  | 24.9
Other Postretirement Benefits |  |  |
Components of net periodic benefit cost (credit) |  |  |
Service cost | 2.8 | 2.8 |
Interest cost | 6.5 | 5.7 |
Expected return on plan assets | (13.6) | (13.2) |
Amortization of prior service credit | (3.2) | (3.4) |
Amortization of net actuarial (gain) loss | (1.4) | (1.9) |
Net periodic benefit (credit) cost | (8.9) | $ (10.0) |
Contributions and payments related to pension and OPEB plans | 0.4 |  |
Estimated future employer contributions for the remainder of the year | 2.2 |  |
Other Postretirement Benefits | Pension and Other Postretirement Plans Cost |  |  |
Components of net periodic benefit cost (credit) |  |  |
Total regulatory assets | $ 33.5 |  | $ 38.2

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