Deferred Revenue And Performance Obligations - Roll Forward (Details) - USD ($) $ in Millions	3 Months Ended			6 Months Ended
	Jun. 29, 2018	Jun. 30, 2017	[1]	Jun. 29, 2018	Jun. 30, 2017	[1]
Revenue Recognition and Deferred Revenue [Abstract]
Beginning Balance of the period	$ 360.4	$ 302.5		$ 276.6	$ 246.4
Revenue recognized	(62.2)	(54.7)		(160.2)	(142.5)
Acquired deferred revenue	1.4	0.6		23.7	4.6
Net deferred revenue activity	56.6	58.9		216.1	198.8
Ending balance of the period	$ 356.2	$ 307.3		$ 356.2	$ 307.3

[1] See Note 2 for a summary of adjustments