PROPERTY, PLANT AND EQUIPMENT (Notes)

12 Months Ended

Dec. 31, 2019

Property, Plant and Equipment [Line Items]

PROPERTY, PLANT AND EQUIPMENT

PROPERTY, PLANT AND EQUIPMENT

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

	December 31,			December 31,
	2019			2018
	(Thousands of dollars)
Natural gas distribution pipelines and related equipment	$	5,117,496		$	4,861,340
Natural gas transmission pipelines and related equipment	549,788			517,697
General plant and other	612,984			567,580
Construction work in process	152,851			126,526
Property, plant and equipment	6,433,119			6,073,143
Accumulated depreciation and amortization	(1,867,893		)	(1,789,431		)
Net property, plant and equipment	$	4,565,226		$	4,283,712

We compute depreciation expense by applying composite, straight-line rates of approximately 2.0 percent to 3.0 percent that were approved by various regulatory authorities.

We recorded capitalized interest of $4.6 million, $3.4 million and $3.0 million for the years ended December 31, 2019, 2018 and 2017, respectively. We incurred liabilities for construction work in process that had not been paid at December 31, 2019, 2018 and 2017 of $20.9 million, $15.6 million and $21.7 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.