Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2016

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



	December 31
	2016		2015
Raw materials	$	271.9	$	260.6
Work in process	12.9		14.2
Finished goods	206.5		189.7
Supplies and materials	232.3		212.3
Inventories	$	723.6	$	676.8

Property, Plant and Equipment (at cost)

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



	December 31
	2016			2015
Land and land improvements	$	149.7		$	146.4
Buildings	717.1			640.9
Machinery and equipment	4,951.4			4,747.1
Construction in progress	125.4			119.1
Other	66.7			61.3
Property, plant, and equipment, at cost	6,010.3			5,714.8
Less accumulated depreciation	(3,114.6		)	(2,882.7		)
Property, plant, and equipment, net	$	2,895.7		$	2,832.1

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 capital 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