Property, Plant and Equipment (Tables)

12 Months Ended

Dec. 31, 2018

Property, Plant and Equipment [Abstract]

Property, plant and equipment

The following is a summary of property, plant and equipment, at cost less accumulated depreciation and amortization as of December 31:

	Estimated Useful Life (years)	2018		2017
Land and land improvements	(1)	$	15.6	$	16.0
Buildings and building improvements	15-30	122.2		112.9
Machinery, tools and equipment	5-12	99.6		108.2
Leasehold improvements (2)	10	26.9		28.3
Computer equipment	3	174.5		153.8
Computer software	5-10	142.9		146.6
Furniture and fixtures	5-8	70.3		73.4
Tooling	3-5	140.9		136.4
Construction in progress		5.3		7.7
Total property plant and equipment, at cost		$	798.2	$	783.3
Less accumulated depreciation and amortization		494.1		418.8
Total property plant and equipment, net		$	304.1	$	364.5

⁽¹⁾  Estimated useful life for land and land improvements is perpetual and 15 years, respectively.

⁽²⁾  The estimated useful life for leasehold improvements is the lesser of 10 years or the term of the lease.