Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2019

Accounting Policies [Abstract]

Components of Inventories

The components of inventories were as follows (dollars in millions):

	December 31,
	2019		2018
Raw materials	$	271.5	$	307.8
Work in process		11.0		13.9
Finished goods		207.7		199.0
Supplies and materials		303.9		274.9
Inventories	$	794.1	$	795.6

Property, Plant and Equipment (at cost)

Property, plant, and equipment consisted of the following (dollars in millions):

	December 31,
	2019			2018
Land and land improvements	$	177.5		$	161.9
Buildings		837.4			795.5
Machinery and equipment		5,727.4			5,481.6
Construction in progress		174.0			176.7
Other		81.5			75.4
Property, plant and equipment, at cost		6,997.8			6,691.1
Less accumulated depreciation		(3,846.1	)		(3,582.5	)
Property, plant and equipment, net	$	3,151.7		$	3,108.6

Property, Plant and Equipment Estimated Useful Lives

Depreciation is computed on the straight-line basis over the estimated useful lives of the related assets. Assets under finance leases are depreciated on the straight-line method over the term of the lease or the useful life, if shorter. The following lives are used for the various categories of assets:

Buildings and land improvements	5 to 40 years
Machinery and equipment	3 to 25 years
Trucks and automobiles	3 to 10 years
Furniture and fixtures	3 to 20 years
Computers and hardware	3 to 10 years
Leasehold improvements	Period of the lease or useful life, if shorter