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v3.24.2

EMPLOYEE BENEFITS-COSTS AND CONTRIBUTIONS (Details) - USD ($) $ in Millions | 3 Months Ended | 6 Months Ended |
--- | --- | --- | ---
Jun. 30, 2024 | Jun. 30, 2023 | Jun. 30, 2024 | Jun. 30, 2023 | Dec. 31, 2023
Components of net periodic benefit cost (credit) |  |  |  |  |
Contributions and payments related to pension and OPEB plans |  |  | $ 7.5 | $ 9.2 |
Total regulatory assets | $ 3,435.0 |  | 3,435.0 |  | $ 3,274.7
Pension Benefits |  |  |  |  |
Components of net periodic benefit cost (credit) |  |  |  |  |
Service cost | 5.4 | $ 5.4 | 12.1 | 12.0 |
Interest cost | 28.8 | 30.4 | 58.3 | 61.2 |
Expected return on plan assets | (45.3) | (46.4) | (91.1) | (93.8) |
Amortization of prior service (credit) cost | 0.0 | 0.0 | 0.0 | 0.1 |
Amortization of net actuarial (gain) loss | 15.3 | 9.3 | 29.7 | 16.7 |
Net periodic benefit (credit) cost | 4.2 | (1.3) | 9.0 | (3.8) |
Contributions and payments related to pension and OPEB plans |  |  | 6.8 |  |
Estimated future employer contributions for the remainder of the year | 6.5 |  | 6.5 |  |
Pension Benefits | Pension and Other Postretirement Plans Cost |  |  |  |  |
Components of net periodic benefit cost (credit) |  |  |  |  |
Total regulatory assets | 15.5 |  | 15.5 |  |
Other Postretirement Benefits |  |  |  |  |
Components of net periodic benefit cost (credit) |  |  |  |  |
Service cost | 2.6 | 2.4 | 5.4 | 4.9 |
Interest cost | 5.7 | 5.4 | 11.4 | 10.8 |
Expected return on plan assets | (13.1) | (13.2) | (26.3) | (26.5) |
Amortization of prior service (credit) cost | (3.4) | (3.7) | (6.8) | (7.4) |
Amortization of net actuarial (gain) loss | (1.9) | (3.0) | (3.8) | (6.2) |
Net periodic benefit (credit) cost | (10.1) | $ (12.1) | (20.1) | $ (24.4) |
Contributions and payments related to pension and OPEB plans |  |  | 0.7 |  |
Estimated future employer contributions for the remainder of the year | 1.3 |  | 1.3 |  |
Other Postretirement Benefits | Pension and Other Postretirement Plans Cost |  |  |  |  |
Components of net periodic benefit cost (credit) |  |  |  |  |
Total regulatory assets | $ 26.5 |  | $ 26.5 |  |

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