Property, Plant and Equipment—Net
Property, plant and equipment—net consists of the following:
 December 31,
 20242023
 (in millions)
Land$114 $114 
Machinery and equipment13,801 13,716 
Buildings and improvements1,011 1,020 
Construction in progress482 394 
Property, plant and equipment(1)
15,408 15,244 
Less: Accumulated depreciation and amortization8,673 8,103 
Property, plant and equipment—net$6,735 $7,141 
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(1)As of December 31, 2024 and 2023, we had property, plant and equipment that was accrued but unpaid of approximately $101 million and $68 million, respectively.

Depreciation and amortization related to property, plant and equipment was $921 million, $861 million and $838 million in 2024, 2023 and 2022, respectively.
Plant turnarounds—Scheduled inspections, replacements and overhauls of plant machinery and equipment at our continuous process manufacturing facilities during a full plant shutdown are referred to as plant turnarounds. The expenditures related to plant turnarounds are capitalized in property, plant and equipment when incurred.
Scheduled replacements and overhauls of plant machinery and equipment during a plant turnaround include the dismantling, repair or replacement and installation of various components including piping, valves, motors, turbines, pumps, compressors and heat exchangers and the replacement of catalysts. Scheduled inspections, including required safety inspections which entail the disassembly of various components such as steam boilers, pressure vessels and other equipment requiring safety certifications, are also conducted during plant turnarounds. Internal employee costs and overhead amounts are not considered plant turnaround costs and are not capitalized.
The following is a summary of capitalized plant turnaround costs:
 Year ended December 31,
 202420232022
 (in millions)
Net capitalized turnaround costs as of January 1$352 $312 $355 
Additions186 165 118 
Depreciation(171)(138)(134)
Impairment related to U.K. operations— — (21)
Acquisition of Waggaman ammonia production facility— 16 — 
Effect of exchange rate changes and other(4)(3)(6)
Net capitalized turnaround costs as of December 31$363 $352 $312 

Historical Timeline

Fiscal YearFiled
2024Feb 20, 2025Showing above
2023Feb 22, 2024
2020Feb 24, 2021
2019Feb 24, 2020
2018Feb 22, 2019
2017Feb 22, 2018
2016Feb 23, 2017
2015Feb 25, 2016

About PP&E Disclosures

The PP&E disclosure details a company's physical asset base — land, buildings, machinery, and equipment — along with the depreciation methods and useful life assumptions that determine how these costs flow through the income statement. Capitalization policy thresholds reveal management's judgment on the boundary between expense and asset, directly affecting both reported earnings and asset values.

Key signals: changes in estimated useful lives or depreciation methods can materially shift reported earnings without any operational change. Compare capital expenditures against depreciation expense — when capex consistently trails depreciation, the asset base may be aging and underinvested. Watch for large asset impairments or write-downs that signal overvalued carrying amounts. Asset retirement obligations reveal future environmental or decommissioning costs that are often underappreciated. Compare PP&E intensity (PP&E-to-revenue) against industry peers to assess capital efficiency and competitive positioning.