Inventories (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013
Inventories
Raw materials	$ 200.4		$ 200.4		$ 189.7
Work-in-process	200.8		200.8		196.5
Finished goods	158.2		158.2		155.3
Demonstration units	52.7		52.7		48.3
Inventories	612.1		612.1		589.8
Inventory-in-transit	71.5		71.5		81.9
Write-down of demonstration units	$ 7.6	$ 8.2	$ 15.2	$ 16.0