Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2017

Estimated useful lives of property, plant and equipment

Depreciation is computed using the straight-line method over the following estimated useful lives:



Buildings and improvements:
Buildings and improvements	2 to 33 years
Leasehold improvements	1 to 39 years
Machinery and equipment:
Computer hardware	3 to 5 years
Computer software	3 to 10 years
Factory machinery and equipment	1 to 15 years
Research and development equipment	3 to 10 years
Vehicles	2 to 8 years

Components of Property, plant and equipment, net were as follows (in millions):



	As of December 31,
	2017			2016
Land	$	35.7		$	33.9
Buildings and improvements	234.4			218.2
Machinery and equipment	804.4			742.1
Capital leases	27.5			27.3
Construction in progress and equipment not yet in service	70.0			57.1
Total	1,172.0			1,078.6
Less accumulated depreciation	(774.2		)	(717.2		)
Property, plant and equipment, net	$	397.8		$	361.4

Identifiable intangible and other assets that have finite lives are amortized over their estimated useful lives

We amortize intangible assets and other assets with finite lives over their respective estimated useful lives to their estimated residual values, as follows:



Asset	Useful Life
Deferred financing costs	Effective interest method
Customer relationships	Straight-line method up to 12 years
Patents and others	Straight-line method up to 20 years