Other Financial Information, Deferred Revenue (Details) - USD ($) $ in Millions	Jun. 30, 2015	Dec. 31, 2014
Deferred revenue:
Total deferred revenue	$ 1,104.4	$ 1,075.7
Reported as:
Current	795.4	780.8
Long-term	309.0	294.9
Total deferred revenue	1,104.4	1,075.7
Sales Revenue, Product, Net [Member]
Deferred revenue:
Undelivered product commitments and other product deferrals	185.6	180.3
Distributor inventory and other sell-through items	62.3	103.7
Deferred gross product revenue	247.9	284.0
Deferred cost of product revenue	(42.8)	(58.4)
Total deferred revenue	205.1	225.6
Reported as:
Total deferred revenue	205.1	225.6
Sales Revenue, Service, Net [Member]
Deferred revenue:
Total deferred revenue	899.3	850.1
Reported as:
Total deferred revenue	$ 899.3	$ 850.1