Other Financial Information, Deferred Revenue (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Deferred product revenue:
Deferred revenue, net	$ 1,539.3	$ 1,481.1
Reported as:
Deferred revenue, current	1,030.3	1,032.0
Deferred revenue, long-term	509.0	449.1
Deferred product revenue:
Deferred product revenue:
Undelivered product commitments and other product deferrals	312.6	302.4
Distributor inventory and other sell-through items	68.1	74.2
Deferred gross product revenue	380.7	376.6
Deferred cost of product revenue	(46.5)	(53.7)
Deferred revenue, net	$ 334.2	322.9
Deferred product revenue, net
Deferred product revenue:
Deferred revenue, net		$ 1,158.2