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Employee Postretirement Benefits (Tables)

12 Months Ended

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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