Property, plant, and equipment are recorded at cost, net of accumulated depreciation and impairments. Costs of routine maintenance and repair are expensed when incurred.

The Company capitalizes certain qualified costs incurred in connection with the development of software used internally. Costs incurred during the application development stage are evaluated to determine whether the costs meet the criteria for capitalization. Costs related to preliminary project activities and post implementation activities that are not incremental upgrades, including maintenance, are expensed as incurred.

Property, plant, and equipment are primarily depreciated using the straight-line method over the estimated useful life of the asset. Land is not depreciated.

The following table summarizes the components of “Property, plant, and equipment, net” on the Consolidated Balance Sheets (in millions):


	Estimated Useful Lives	December 31, 2022		December 31, 2023
Land, buildings, and building improvements	10 to 30 years	$	636	$	972
Leasehold improvements	Shorter of 10 years or lease term	297		417
Machinery, equipment, vehicles, and office furniture	2 to 10 years	2,456		3,068
Computer equipment, hardware, and software	3 to 5 years	409		515
Construction in progress		843		698
Total property, plant, and equipment		4,641		5,670
Accumulated depreciation and amortization		(883)		(1,796)
Total property, plant, and equipment, net		$	3,758	$	3,874

Depreciation and amortization expense was $197 million, $647 million, and $917 million for the years ended December 31, 2021, 2022 and 2023, respectively.