The major classes of plant and equipment are as follows:
30 SeptemberUseful life20252024
Land$343.0 $312.1 
Buildings30 years1,766.1 1,730.7 
Production facilities(A)
10-20 years
21,412.9 21,245.2 
Distribution and other machinery and equipment(B)
5-25 years
5,776.0 5,472.7 
Construction in progress13,456.8 11,190.2 
Plant and equipment, at cost$42,754.8 $39,950.9 
Less: Accumulated depreciation17,417.0 16,580.0 
Plant and equipment, net$25,337.8 $23,370.9 
(A)Depreciable lives of production facilities related to long-term customer supply contracts are generally matched to the contract lives.
(B)The depreciable lives for various types of distribution equipment are: 10 to 25 years for cylinders, depending on the nature and properties of the product; 20 years for tanks; generally 7.5 years for customer stations; and 5 to 15 years for tractors and trailers.

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.