Recent Accounting Changes and Pronouncements - Narrative (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Other income (expense) – net	$ 5.6	$ (1.2)	$ 2.9	$ 0.9
Engineering, selling, and administrative expense	$ (62.1)	(58.4)	(122.5)	(119.8)
Operating cash flows			281.0	190.9
Investing cash flows			$ 243.9	139.9
Accounting Standards Update 2017-07
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Other income (expense) – net		1.9		3.8
Engineering, selling, and administrative expense		$ 1.9		3.8
Accounting Standards Update 2016-15
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Operating cash flows				146.3
Investing cash flows				$ 146.3