Property, Plant, and Equipment

12 Months Ended

Dec. 31, 2025

Property, Plant and Equipment [Abstract]

Property, Plant and Equipment Disclosure

PROPERTY, PLANT AND EQUIPMENT

The following table sets forth our property, plant and equipment by property type, for the periods indicated:

	December 31,
	2025		2024
	(Thousands of dollars)
Natural gas distribution pipelines and related equipment	$	7,797,444	$	7,278,542
Natural gas transmission pipelines and related equipment	771,304		736,229
General plant and other	1,066,476		942,677
Construction work in process	98,926		166,686
Property, plant and equipment	9,734,150		9,124,134
Accumulated depreciation and amortization	(2,611,952)		(2,478,261)
Net property, plant and equipment	$	7,122,198	$	6,645,873

We compute depreciation expense by applying composite, straight-line rates of approximately 2.7 percent to 3.2 percent as approved by various regulatory authorities.

We recorded capitalized interest of $11.8 million, $8.2 million, and $5.7 million for the years ended December 31, 2025, 2024, and 2023, respectively. We incurred liabilities for construction work in process and asset removal costs that had not been paid at December 31, 2025, 2024, and 2023 of $28.9 million, $33.7 million, and $36.2 million, respectively. Such amounts are not included in capital expenditures or in the change of working capital items on our consolidated statements of cash flows.

The allowance for earnings on shareholders’ investment capitalized for regulatory purposes but not recorded for financial reporting purposes is $24.2 million and $17.4 million at December 31, 2025 and December 31, 2024, respectively.