At the end of fiscal years 2020 and 2019, property, plant and equipment at cost and accumulated depreciation were:


(Dollars in Millions)	2020		2019
Land and land improvements	$	882	854
Buildings and building equipment	12,502		11,877
Machinery and equipment	29,104		26,964
Construction in progress	4,316		3,637
Total property, plant and equipment, gross	$	46,804	43,332
Less accumulated depreciation	28,038		25,674
Total property, plant and equipment, net(1)	$	18,766	17,658

(1) See Note 18 to the Consolidated Financial Statements for details on assets held for sale and the related divestitures for the fiscal year ended December 29, 2019. There were no assets held for sale at January 3, 2021.

The Company capitalizes interest expense as part of the cost of construction of facilities and equipment. Interest expense capitalized in fiscal years 2020, 2019 and 2018 was $63 million, $70 million and $86 million, respectively.

Depreciation expense, including the amortization of capitalized interest in fiscal years 2020, 2019 and 2018 was $2.6 billion, $2.5 billion and $2.6 billion, respectively.

Upon retirement or other disposal of property, plant and equipment, the costs and related amounts of accumulated depreciation or amortization are eliminated from the asset and accumulated depreciation accounts, respectively. The difference, if any, between the net asset value and the proceeds are recorded in earnings.