Property, Plant and Equipment (Tables)

12 Months Ended

Dec. 31, 2020

Property, Plant and Equipment [Abstract]

Classes of Property, Plant and Equipment

Provisions for depreciation and amortization have been computed principally by the straight-line method based on the estimated useful lives of the depreciable assets as follows:

Category	Useful Life
Buildings	30 years
Leased assets and leasehold improvements	Amortized over the lesser of the economic life of the asset or the term of the lease
Machinery and equipment	3 – 10 years

The classes of property, plant and equipment as of December 31 are summarized as follows:

($ in millions)	2020		2019
Land and improvements	$	6.1	$	6.2
Buildings and leasehold improvements	65.5		57.3
Machinery and equipment	265.6		263.7
Gross property, plant and equipment	337.2		327.2
Less: accumulated depreciation	(240.4)		(225.3)
Property, plant and equipment, net (a)	$	96.8	$	101.9
(a) Includes property, plant and equipment, net in the United States of $74.0 million and $78.5 million as of December 31, 2020 and 2019, respectively.