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Employee Postretirement Benefits (Tables) | 12 Months Ended
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Dec. 31, 2024
Retirement Benefits [Abstract] |
Schedule of Target Asset Allocation Ranges By Asset Class | The following table presents our target asset allocation permitted range along with the actual asset allocation as of December 31, 2024 and 2023:
| Permitted |  | Actual Allocation
Asset Class | Range |  | 2024 |  | 2023
Return Enhancement | 35 |  | – | 60% |  | 41 | % |  | 48 | %
Risk Management | 40 |  | – | 80% |  | 59 |  |  | 51 |
Alternatives | 0 |  | – | 20% |  | — |  |  | 1 |
Total |  |  |  |  | 100 | % |  | 100 | %
Schedule of Allocation of Plan Assets | The following presents the fair value inputs classified within the fair value hierarchy used to measure Pension Plan assets at December 31, 2024 and 2023 and assets measured using the net asset value (NAV) practical expedient:
(in thousands) | Level 1 |  | Level 2 |  | Level 3 |  | NAV |  | Total
December 31, 2024 |  |  |  |  |  |  |  |  |
Equity Funds | $ | 116,889 |  |  | $ | — |  |  | $ | — |  |  | $ | — |  |  | $ | 116,889 |
Fixed Income Funds | 175,310 |  |  | — |  |  | — |  |  | — |  |  | 175,310 |
Hybrid Funds | 10,106 |  |  | — |  |  | — |  |  | — |  |  | 10,106 |
U.S. Treasury Securities | 23,909 |  |  | — |  |  | — |  |  | — |  |  | 23,909 |
SEI Energy Debt Collective Fund | — |  |  | — |  |  | — |  |  | 1,061 |  |  | 1,061 |
Total | $ | 326,214 |  |  | $ | — |  |  | $ | — |  |  | $ | 1,061 |  |  | $ | 327,275 |
December 31, 2023 |  |  |  |  |  |  |  |  |
Equity Funds | $ | 127,159 |  |  | $ | — |  |  | $ | — |  |  | $ | — |  |  | $ | 127,159 |
Fixed Income Funds | 167,604 |  |  | — |  |  | — |  |  | — |  |  | 167,604 |
Hybrid Funds | 10,980 |  |  | — |  |  | — |  |  | — |  |  | 10,980 |
U.S. Treasury Securities | 23,218 |  |  | — |  |  | — |  |  | — |  |  | 23,218 |
SEI Energy Debt Collective Fund | — |  |  | — |  |  | — |  |  | 1,518 |  |  | 1,518 |
Total | $ | 328,961 |  |  | $ | — |  |  | $ | — |  |  | $ | 1,518 |  |  | $ | 330,479 |
Schedule of Changes in Projected Benefit Obligations and Changes in Plan Assets | The following table provides a reconciliation of the changes in the fair value of plan assets and the actuarially computed benefit obligation for the years ended December 31, 2024 and 2023 and the funded status of the plans as of December 31, 2024 and 2023:
| Pension Benefits (Pension Plan) |  | Pension Benefits (ESSRP) |  | Postretirement Benefits
(in thousands) | 2024 |  | 2023 |  | 2024 |  | 2023 |  | 2024 |  | 2023
Change in Fair Value of Plan Assets: |  |  |  |  |  |  |  |  |  |  |
Fair Value of Plan Assets at January 1 | $ | 330,479 |  |  | $ | 313,797 |  |  | $ | — |  |  | $ | — |  |  | $ | — |  |  | $ | — |
Actual Return on Plan Assets | 14,976 |  |  | 34,196 |  |  | — |  |  | — |  |  | — |  |  | — |
Company Contributions | — |  |  | — |  |  | 2,694 |  |  | 2,197 |  |  | 1,568 |  |  | 3,167 |
Benefit Payments | (18,180) |  |  | (17,514) |  |  | (2,694) |  |  | (2,197) |  |  | (3,734) |  |  | (8,900) |
Participant Premium Payments | — |  |  | — |  |  | — |  |  | — |  |  | 2,166 |  |  | 5,733 |
Fair Value of Plan Assets at December 31 | $ | 327,275 |  |  | $ | 330,479 |  |  | $ | — |  |  | $ | — |  |  | $ | — |  |  | $ | — |
Change in Benefit Obligation: |  |  |  |  |  |  |  |  |  |  |
Benefit Obligation at January 1 | $ | 318,801 |  |  | $ | 308,055 |  |  | $ | 35,780 |  |  | $ | 35,624 |  |  | $ | 30,145 |  |  | $ | 49,947 |
Service Cost | 3,886 |  |  | 3,698 |  |  | — |  |  | 72 |  |  | 490 |  |  | 565 |
Interest Cost | 17,189 |  |  | 16,436 |  |  | 1,897 |  |  | 1,889 |  |  | 1,600 |  |  | 2,416 |
Benefit Payments | (18,180) |  |  | (17,514) |  |  | (2,694) |  |  | (2,197) |  |  | (3,734) |  |  | (8,900) |
Participant Premium Payments | — |  |  | — |  |  | — |  |  | — |  |  | 2,166 |  |  | 5,733 |
Plan Amendments | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  | (17,493) |
Actuarial (Gain) Loss | (7,686) |  |  | 8,126 |  |  | 331 |  |  | 392 |  |  | (664) |  |  | (2,123) |
Benefit Obligation at December 31 | 314,010 |  |  | 318,801 |  |  | 35,314 |  |  | 35,780 |  |  | 30,003 |  |  | 30,145 |
Funded Status | $ | 13,265 |  |  | $ | 11,678 |  |  | $ | (35,314) |  |  | $ | (35,780) |  |  | $ | (30,003) |  |  | $ | (30,145) |
Amounts Recognized in Consolidated Balance Sheets at December 31: |  |  |  |  |  |  |  |
Noncurrent Assets | $ | 13,265 |  |  | $ | 11,678 |  |  | $ | — |  |  | $ | — |  |  | $ | — |  |  | $ | — |
Current Liabilities | — |  |  | — |  |  | (2,700) |  |  | (2,679) |  |  | (2,618) |  |  | (2,469) |
Noncurrent Liabilities | — |  |  | — |  |  | (32,614) |  |  | (33,101) |  |  | (27,385) |  |  | (27,676) |
Net Asset (Liability) | $ | 13,265 |  |  | $ | 11,678 |  |  | $ | (35,314) |  |  | $ | (35,780) |  |  | $ | (30,003) |  |  | $ | (30,145) |
Schedule of Assumptions Used in Calculating Net Periodic Benefit Cost | The following assumptions were used to determine benefit obligations as of December 31, 2024 and 2023:
| Pension Benefits (Pension Plan) |  | Pension Benefits (ESSRP) |  | Postretirement Benefits
| 2024 |  | 2023 |  | 2024 |  | 2023 |  | 2024 |  | 2023
Discount Rate | 5.70 | % |  | 5.57 | % |  | 5.60 | % |  | 5.53 | % |  | 5.61 | % |  | 5.53 | %
Long-Term Rate of Compensation Increase | n/a |  | n/a |  | 3.00 | % |  | 3.00 | % |  | n/a |  | n/a
Participants up to Age 39(1) | 4.50 | % |  | 4.50 | % |  | n/a |  | n/a |  | n/a |  | n/a
Participants Ages 40 to 49(2) | 4.50 | % |  | 4.50 | % |  | n/a |  | n/a |  | n/a |  | n/a
Participants Age 50 and Older(3) | 3.75 | % |  | 3.75 | % |  | n/a |  | n/a |  | n/a |  | n/a
Healthcare Cost Immediate Trend Rate | n/a |  | n/a |  | n/a |  | n/a |  | 6.44 | % |  | 6.97 | %
Healthcare Cost Ultimate Trend Rate | n/a |  | n/a |  | n/a |  | n/a |  | 4.00 | % |  | 4.00 | %
Year the Rate Reaches the Ultimate Trend Rate | n/a |  | n/a |  | n/a |  | n/a |  | 2048 |  | 2048
(1) Amount reflects rate of compensation increases for both union and non-union employees.
(2) Amount reflects rate of compensation increases for union employees. The rate of compensation increases for non-union employees is 3.50%.
(3) Amount reflects rate of compensation increases for union employees. The rate of compensation increases for non-union employees is 3.00%.
The following assumptions were used to determine net periodic benefit cost for the years ended December 31, 2024, 2023 and 2022:
| Pension Benefits (Pension Plan) |  | Pension Benefits (ESSRP) |  | Postretirement Benefits
| 2024 |  | 2023 |  | 2022 |  | 2024 |  | 2023 |  | 2022 |  | 2024 |  | 2023 |  | 2022
Discount Rate | 5.57 | % |  | 5.51 | % |  | 3.03 | % |  | 5.53 | % |  | 5.51 | % |  | 2.93 | % |  | 5.53 | % |  | 5.52 | % |  | 3.01 | %
Long-Term Rate of Return on Plan Assets | 7.00 | % |  | 7.00 | % |  | 6.30 | % |  | n/a |  | n/a |  | n/a |  | n/a |  | n/a |  | n/a
Long-Term Rate of Compensation Increase | n/a |  | n/a |  | n/a |  | 3.00 | % |  | 3.00 | % |  | 3.00 | % |  | n/a |  | n/a |  | n/a
Participants to Age 39 | 4.50 | % |  | 4.50 | % |  | 4.50 | % |  | n/a |  | n/a |  | n/a |  | n/a |  | n/a |  | n/a
Participants Ages 40 to 49 | 4.00 | % |  | 3.50 | % |  | 3.50 | % |  | n/a |  | n/a |  | n/a |  | n/a |  | n/a |  | n/a
Participants Age 50 and Older | 3.38 | % |  | 2.75 | % |  | 2.75 | % |  | n/a |  | n/a |  | n/a |  | n/a |  | n/a |  | n/a
Schedule of Net Benefit Costs | The following table lists the components of net periodic benefit cost of our defined benefit pension plans and other postretirement benefits for the years ended December 31, 2024, 2023 and 2022:
| Pension Benefits (Pension Plan) |  | Pension Benefits (ESSRP) |  | Postretirement Benefits
(in thousands) | 2024 |  | 2023 |  | 2022 |  | 2024 |  | 2023 |  | 2022 |  | 2024 |  | 2023 |  | 2022
Service Cost | $ | 3,886 |  |  | $ | 3,698 |  |  | $ | 6,576 |  |  | $ | — |  |  | $ | 72 |  |  | $ | 195 |  |  | $ | 490 |  |  | $ | 565 |  |  | $ | 1,338 |
Interest Cost | 17,189 |  |  | 16,436 |  |  | 12,344 |  |  | 1,897 |  |  | 1,889 |  |  | 1,341 |  |  | 1,600 |  |  | 2,416 |  |  | 2,041 |
Expected Return on Assets | (25,518) |  |  | (25,914) |  |  | (23,684) |  |  | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  | — |
Amortization of Prior Service Cost | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  | (6,302) |  |  | (6,649) |  |  | (5,733) |
Amortization of Net Actuarial Loss | 158 |  |  | — |  |  | 7,865 |  |  | — |  |  | — |  |  | 567 |  |  | — |  |  | — |  |  | 3,063 |
Net Periodic Benefit Cost | $ | (4,285) |  |  | $ | (5,780) |  |  | $ | 3,101 |  |  | $ | 1,897 |  |  | $ | 1,961 |  |  | $ | 2,103 |  |  | $ | (4,212) |  |  | $ | (3,668) |  |  | $ | 709 |
The following table includes the impact of regulation on the recognition of periodic benefit cost arising from pension and other postretirement benefits for the years ended December 31, 2024, 2023 and 2022:
(in thousands) | 2024 |  | 2023 |  | 2022
Net Periodic Benefit Cost | $ | (6,600) |  |  | $ | (7,487) |  |  | $ | 5,913 |
Net Amount Amortized Due to the Effect of Regulation | 1,367 |  |  | 1,225 |  |  | 1,121 |
Net Periodic Benefit Cost Recognized | $ | (5,233) |  |  | $ | (6,262) |  |  | $ | 7,034 |
Schedule of Amounts Not Yet Recognized as Components of Net Periodic Benefit Cost | The following table presents the amounts not yet recognized as components of net periodic benefit cost as of December 31, 2024 and 2023:
| Pension Benefits (Pension Plan) |  | Pension Benefits (ESSRP) |  | Postretirement Benefits
(in thousands) | 2024 |  | 2023 |  | 2024 |  | 2023 |  | 2024 |  | 2023
Regulatory Assets (Liabilities): |  |  |  |  |  |  |  |  |  |  |
Unrecognized Prior Service Cost | $ | — |  |  | $ | — |  |  | $ | — |  |  | $ | — |  |  | $ | (12,703) |  |  | $ | (18,845) |
Unrecognized Actuarial Loss | 87,868 |  |  | 85,227 |  |  | 292 |  |  | 1,061 |  |  | 1,121 |  |  | 1,759 |
Net Regulatory Assets (Liabilities) | $ | 87,868 |  |  | $ | 85,227 |  |  | $ | 292 |  |  | $ | 1,061 |  |  | $ | (11,582) |  |  | $ | (17,086) |
Accumulated Other Comprehensive Income (Loss): |  |  |  |  |  |  |  |  |  |  |
Unrecognized Prior Service Cost | $ | — |  |  | $ | — |  |  | $ | — |  |  | $ | — |  |  | $ | 339 |  |  | $ | 498 |
Unrecognized Actuarial Gain (Loss) | 1,937 |  |  | 1,994 |  |  | (2,502) |  |  | (1,403) |  |  | 732 |  |  | 707 |
Total Accumulated Other Comprehensive Income (Loss) | $ | 1,937 |  |  | $ | 1,994 |  |  | $ | (2,502) |  |  | $ | (1,403) |  |  | $ | 1,071 |  |  | $ | 1,205 |
Schedule of Expected Benefit Payments | The following reflects anticipated benefit payments to be paid in each of the next five years and in the aggregate for the five-year period thereafter under our pension plans and postretirement healthcare plan:
(in thousands) | 2025 |  | 2026 |  | 2027 |  | 2028 |  | 2029 |  | 2030-2034
Projected Pension Plan Benefit Payments | $ | 19,274 |  |  | $ | 19,804 |  |  | $ | 20,284 |  |  | $ | 20,859 |  |  | $ | 21,420 |  |  | $ | 111,275 |
Projected ESSRP Benefit Payments | 2,769 |  |  | 2,899 |  |  | 3,059 |  |  | 2,999 |  |  | 3,070 |  |  | 14,275 |
Projected Postretirement Benefit Payments | 2,618 |  |  | 2,614 |  |  | 2,576 |  |  | 2,488 |  |  | 2,517 |  |  | 12,019 |
Total | $ | 24,661 |  |  | $ | 25,317 |  |  | $ | 25,919 |  |  | $ | 26,346 |  |  | $ | 27,007 |  |  | $ | 137,569 |

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