Depreciation and depletion are recorded over the following estimated useful lives:
Asset ClassBasisLife
Land, land improvements and mineral rights
Land and mineral rightsUnits of productionLife of mine
Land improvementsStraight line
20 to 45 years
BuildingsStraight line
20 to 45 years
EquipmentStraight line/Double declining balance
3 to 45 years
The following table indicates the carrying value of each of the major classes of our depreciable assets:
December 31,
(In millions)20252024
Land, land improvements and mineral rights$1,463 $1,451 
Buildings1,205 1,104 
Equipment11,630 11,119 
Other357 349 
Construction in progress655 728 
Total property, plant and equipment1
15,310 14,751 
Allowance for depreciation and depletion(5,829)(4,809)
Property, plant and equipment, net$9,481 $9,942 
1 Includes right-of-use assets related to finance leases of $576 million and $505 million as of December 31, 2025 and 2024, respectively.
The net book value of the mineral and land rights are as follows:
December 31,
(In millions)20252024
Mineral rights:
Cost$783 $783 
Depletion(301)(287)
Net mineral rights$482 $496 
Land rights$457 $467 

Historical Timeline

Fiscal YearFiled
2025Feb 9, 2026Showing above
2024Feb 25, 2025
2023Feb 8, 2024
2022Feb 14, 2023
2021Feb 11, 2022
2020Feb 26, 2021
2019Feb 20, 2020
2018Feb 8, 2019
2017Feb 14, 2018
2016Feb 9, 2017
2015Feb 24, 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.