Other Financial Information - Deferred Revenue (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Deferred revenue:
Deferred revenue	$ 1,223.4	$ 1,213.6
Reported as:
Current deferred revenue	812.9	829.3
Long-term deferred revenue	410.5	384.3
Undelivered Product Commitments and Other Product Deferrals [Member]
Deferred revenue:
Deferred revenue, gross	141.7	163.3
Product
Deferred revenue:
Deferred revenue, gross	141.7	163.3
Deferred cost	(9.1)	(18.9)
Deferred revenue	132.6	144.4
Service
Deferred revenue:
Deferred revenue, gross	1,090.8	1,071.8
Deferred cost	0.0	(2.6)
Deferred revenue	$ 1,090.8	$ 1,069.2