Regulatory Assets and Liabilities (Tables)

12 Months Ended

Dec. 31, 2024

Regulatory Assets and Liabilities Disclosure [Abstract]

The following table summarizes the individual components of unamortized regulatory assets and liabilities as of December 31:


	Estimated Recovery or Refund Period	*	2024		2023
			(In thousands)
Regulatory assets:
Current:
Natural gas costs recoverable through rate adjustments	Up to 1 year		$	91,091	$	98,844
Environmental compliance programs	Up to 1 year		76,964		5,525
Conservation programs	Up to 1 year		19,123		14,425
Electric fuel and purchased power deferral	Up to 1 year		9,662		33,918
Decoupling mechanisms	Up to 1 year		6,767		—
Cost recovery mechanisms	Up to 1 year		5,114		9,153
Other	Up to 1 year		6,715		10,627
			215,436		172,492
Noncurrent:
Pension and postretirement benefits	**		142,064		142,511
Cost recovery mechanisms	Up to 24 years		76,542		85,944
Plant costs/asset retirement obligations	Over plant lives		47,042		46,009
Manufactured gas plant site remediation	-		27,964		26,127
Taxes recoverable from customers	Over plant lives		12,221		12,249
Electric fuel and purchased power deferral	Up to 2 years		4,349		—
Covid-19 deferred costs	-		4,167		2,746
Long-term debt refinancing costs	Up to 36 years		2,011		2,600
Environmental compliance programs	-		—		66,806
Natural gas costs recoverable through rate adjustments	Up to 2 years		—		55,493
Other	Up to 14 years		5,990		6,614
			322,350		447,099
Total regulatory assets			$	537,786	$	619,591
Regulatory liabilities:
Current:
Environmental compliance	Up to 1 year		$	72,387	$	—
Natural gas costs refundable through rate adjustments	Up to 1 year		45,427		43,161
Margin sharing	Up to 1 year		4,156		5,243
Provision for rate refund	Up to 1 year		3,677		6,866
Taxes refundable to customers	Up to 1 year		2,163		2,149
Conservation programs	Up to 1 year		2,082		2,130
Cost recovery mechanisms	Up to 1 year		1,720		6,284
Other	Up to 1 year		5,555		4,928
			137,167		70,761
Noncurrent:
Plant removal and decommissioning costs	Over plant lives		217,603		220,147
Taxes refundable to customers	Over plant lives		185,402		193,578
Cost recovery mechanisms	Up to 17 years		30,354		21,791
Accumulated deferred investment tax credit	Over plant lives		18,788		15,740
Pension and postretirement benefits	**		4,862		6,044
Environmental compliance programs	-		—		61,941
Other	Up to 13 years		2,161		1,809
			459,170		521,050
Total regulatory liabilities			$	596,337	$	591,811
Net regulatory position			$	(58,551)	$	27,780

*Estimated recovery or refund period for amounts currently being recovered or refunded in rates to customers.

** Recovered as expense is incurred or cash contributions are made.

Schedule of Regulatory Liabilities

The following table summarizes the individual components of unamortized regulatory assets and liabilities as of December 31:


	Estimated Recovery or Refund Period	*	2024		2023
			(In thousands)
Regulatory assets:
Current:
Natural gas costs recoverable through rate adjustments	Up to 1 year		$	91,091	$	98,844
Environmental compliance programs	Up to 1 year		76,964		5,525
Conservation programs	Up to 1 year		19,123		14,425
Electric fuel and purchased power deferral	Up to 1 year		9,662		33,918
Decoupling mechanisms	Up to 1 year		6,767		—
Cost recovery mechanisms	Up to 1 year		5,114		9,153
Other	Up to 1 year		6,715		10,627
			215,436		172,492
Noncurrent:
Pension and postretirement benefits	**		142,064		142,511
Cost recovery mechanisms	Up to 24 years		76,542		85,944
Plant costs/asset retirement obligations	Over plant lives		47,042		46,009
Manufactured gas plant site remediation	-		27,964		26,127
Taxes recoverable from customers	Over plant lives		12,221		12,249
Electric fuel and purchased power deferral	Up to 2 years		4,349		—
Covid-19 deferred costs	-		4,167		2,746
Long-term debt refinancing costs	Up to 36 years		2,011		2,600
Environmental compliance programs	-		—		66,806
Natural gas costs recoverable through rate adjustments	Up to 2 years		—		55,493
Other	Up to 14 years		5,990		6,614
			322,350		447,099
Total regulatory assets			$	537,786	$	619,591
Regulatory liabilities:
Current:
Environmental compliance	Up to 1 year		$	72,387	$	—
Natural gas costs refundable through rate adjustments	Up to 1 year		45,427		43,161
Margin sharing	Up to 1 year		4,156		5,243
Provision for rate refund	Up to 1 year		3,677		6,866
Taxes refundable to customers	Up to 1 year		2,163		2,149
Conservation programs	Up to 1 year		2,082		2,130
Cost recovery mechanisms	Up to 1 year		1,720		6,284
Other	Up to 1 year		5,555		4,928
			137,167		70,761
Noncurrent:
Plant removal and decommissioning costs	Over plant lives		217,603		220,147
Taxes refundable to customers	Over plant lives		185,402		193,578
Cost recovery mechanisms	Up to 17 years		30,354		21,791
Accumulated deferred investment tax credit	Over plant lives		18,788		15,740
Pension and postretirement benefits	**		4,862		6,044
Environmental compliance programs	-		—		61,941
Other	Up to 13 years		2,161		1,809
			459,170		521,050
Total regulatory liabilities			$	596,337	$	591,811
Net regulatory position			$	(58,551)	$	27,780

*Estimated recovery or refund period for amounts currently being recovered or refunded in rates to customers.

** Recovered as expense is incurred or cash contributions are made.