| Schedule of Components of Net Periodic Benefit Expense |
The table that follows provides the components of net periodic benefit expense for the three and nine months ended September 30, 2026 and 2025. | | | | | | | | | | | | | | | | | | | | | | | | | Three Months Ended September 30, | | Pension Benefits | | Other Postretirement Benefits | | (Thousands of dollars) | 2026 | | 2025 | | 2026 | | 2025 | | Service cost | $ | 1,865 | | | $ | 1,683 | | | $ | 102 | | | $ | 84 | | | Interest cost | 7,744 | | | 8,495 | | | 750 | | | 708 | | | Expected return on plan assets | (8,786) | | | (8,967) | | | — | | | — | | | Estimated defined contribution provision | 69 | | | 62 | | | — | | | — | | | Amortization of prior service cost (credit) | 432 | | | 492 | | | (133) | | | (133) | | | Recognized actuarial (gain) loss | 1,643 | | | 1,918 | | | (386) | | | (1,057) | | | | | | | | | | | | | | | | | | | | | | | | | | | Total net periodic benefit cost (credit) | $ | 2,967 | | | $ | 3,683 | | | $ | 333 | | | $ | (398) | | | | | | | | | | | Nine Months Ended September 30, | | Pension Benefits | | Other Postretirement Benefits | | (Thousands of dollars) | 2026 | | 2025 | | 2026 | | 2025 | | Service cost | $ | 5,595 | | | $ | 5,049 | | | $ | 306 | | | $ | 252 | | | Interest cost | 23,248 | | | 25,375 | | | 2,250 | | | 2,124 | | | Expected return on plan assets | (26,370) | | | (26,791) | | | — | | | — | | | Estimated defined contribution provision | 209 | | | 184 | | | — | | | — | | | Amortization of prior service cost (credit) | 1,296 | | | 1,475 | | | (399) | | | (399) | | | Recognized actuarial (gain) loss | 4,931 | | | 5,723 | | | (1,160) | | | (3,170) | | | Total net periodic benefit cost (credit) | $ | 8,909 | | | $ | 11,015 | | | $ | 997 | | | $ | (1,193) | | | | | | | | | | | | | | | | | | | | | | | | | |
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