Other Financial Information - Deferred Revenue (Details) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Deferred product revenue:
Deferred revenue	$ 1,501.0	$ 1,481.1
Reported as:
Current	998.0	1,032.0
Long-term	503.0	449.1
Deferred revenue	1,501.0	1,481.1
Sales Revenue, Product, Net [Member]
Deferred product revenue:
Undelivered product commitments and other product deferrals	265.5	302.4
Distributor inventory and other sell-through items	76.1	74.2
Deferred gross product revenue	341.6	376.6
Deferred cost of product revenue	(44.3)	(53.7)
Deferred revenue	297.3	322.9
Reported as:
Deferred revenue	297.3	322.9
Sales Revenue, Service, Net [Member]
Deferred product revenue:
Deferred revenue	1,203.7	1,158.2
Reported as:
Deferred revenue	$ 1,203.7	$ 1,158.2