Inventories (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015
Inventories
Raw materials	$ 141.2		$ 158.8
Work-in-process	188.7		131.1
Finished goods	91.3		93.3
Demonstration units	38.9		38.8
Inventories	460.1		422.0
Inventory-in-transit	40.8		$ 44.7
Write-down of demonstration inventories to net realizable value	$ 4.8	$ 5.0