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PROPERTY, PLANT AND EQUIPMENT (Notes) | 12 Months Ended
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Dec. 31, 2018
Property, Plant and Equipment [Line Items] |
PROPERTY, PLANT AND EQUIPMENT |
10. | 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,
|  | 2018 |  | 2017
|  | (Thousands of dollars)
Natural gas distribution pipelines and related equipment |  | $ | 4,861,340 |  |  | $ | 4,572,343 |
Natural gas transmission pipelines and related equipment |  | 517,697 |  |  | 497,791 |
General plant and other |  | 567,580 |  |  | 513,445 |
Construction work in process |  | 126,526 |  |  | 130,333 |
Property, plant and equipment |  | 6,073,143 |  |  | 5,713,912 |
Accumulated depreciation and amortization |  | (1,789,431 | ) |  | (1,706,327 | )
Net property, plant and equipment |  | $ | 4,283,712 |  |  | $ | 4,007,585 |
We compute depreciation expense by applying composite, straight-line rates of 2.0 percent to 3.0 percent that were approved by various regulatory authorities. We recorded capitalized interest of $3.4 million, $3.0 million and $3.6 million for the years ended December 31, 2018, 2017 and 2016, respectively. We incurred liabilities for construction work in process and asset removal costs that had not been paid at December 31, 2018, 2017 and 2016 of $15.6 million, $21.7 million and $11.9 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.

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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
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- Definition The entire disclosure for long-lived, physical assets used in the normal conduct of business and not intended for resale. Includes, but is not limited to, accounting policies and methodology, roll forwards, depreciation, depletion and amortization expense, including composite depreciation, accumulated depreciation, depletion and amortization expense, useful lives and method used, income statement disclosures, assets held for sale and public utility disclosures. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 360 -URI http://asc.fasb.org/topic&trid=2155823 + Details
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