Depreciable property is depreciated over the estimated useful lives of the assets, using principally the straight-line method as follows:
Buildings and improvements
10 to 40 years
Machinery and equipment
5 to 15 years
A summary of property, plant and equipment is shown below (in millions):
December 31,20252024
Land$102.9 $98.6 
Buildings and improvements1,004.0 898.3 
Machinery and equipment5,984.9 5,485.2 
Construction in progress355.3 335.8 
Total property, plant and equipment7,447.1 6,817.9 
Less – accumulated depreciation(4,534.0)(3,984.5)
Net property, plant and equipment$2,913.1 $2,833.4 

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.