Other Financial Information, Deferred Revenue (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Deferred Revenue [Abstract]
Deferred revenue, net	$ 1,168.1	$ 1,075.7
Deferred Revenue Reported as [Abstract]
Deferred revenue, current	822.9	780.8
Deferred revenue, long-term	345.2	294.9
Deferred product revenue [Member]
Deferred Revenue [Abstract]
Undelivered product commitments and other product deferrals	210.1	180.3
Distributor inventory and other sell-through items	81.8	103.7
Deferred gross product revenue	291.9	284.0
Deferred cost of product revenue	(51.6)	(58.4)
Deferred revenue, net	240.3	225.6
Deferred service revenue [Member]
Deferred Revenue [Abstract]
Deferred revenue, net	$ 927.8	$ 850.1