Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2017

Accounting Policies [Abstract]

Components of Inventories

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

	December 31
	2017		2016
Raw materials	$	279.8	$	271.9
Work in process		12.6		12.9
Finished goods		217.0		206.5
Supplies and materials		253.1		232.3
Inventories	$	762.5	$	723.6

Property, Plant and Equipment (at cost)

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

	December 31
	2017			2016
Land and land improvements	$	156.0		$	149.7
Buildings		729.8			717.1
Machinery and equipment		5,162.5			4,951.4
Construction in progress		194.5			125.4
Other		68.4			66.7
Property, plant and equipment, at cost		6,311.2			6,010.3
Less accumulated depreciation		(3,386.3	)		(3,114.6	)
Property, plant and equipment, net	$	2,924.9		$	2,895.7

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 leaseor useful life, if shorter