Property, Plant, and Equipment

6 Months Ended

Jun. 30, 2022

Property, Plant and Equipment [Abstract]

9. Property, Plant, and Equipment

The components of property, plant, and equipment were as follows (dollars in millions):


	June 30,			December 31,
	2022			2021
Land and land improvements	$	192.5		$	189.8
Buildings		973.6			938.7
Machinery and equipment		6,359.6			6,159.1
Construction in progress		607.0			481.0
Other		122.2			102.9
Property, plant and equipment, at cost		8,254.9			7,871.5
Less accumulated depreciation		(4,492.0	)		(4,342.5	)
Property, plant, and equipment, net	$	3,762.9		$	3,529.0

Depreciation expense for the three months ended June 30, 2022 and 2021 was $103.5 million and $94.5 million, respectively. During the six months ended June 30, 2022 and 2021, depreciation expense was $202.1 million and $184.5 million, respectively. We recognized $1.7 million of incremental depreciation expense during the six months ended June 30, 2022 as a result of Jackson mill conversion-related activities. We recognized $2.1 million of incremental depreciation expense during the six months ended June 30, 2021 as a result of closure costs related to corrugated products facilities and Jackson mill conversion-related activities.

At June 30, 2022 and December 31, 2021, purchases of property, plant, and equipment included in accounts payable were $118.3 million and