Segment Information (Reconciliation Of Our Condensed Consolidated Segment Operating Income To Condensed Consolidated Income Before Income Taxes) (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Oct. 01, 2021	Oct. 02, 2020	Oct. 01, 2021	Oct. 02, 2020
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Consolidated operating income	$ 147.5	$ 102.0	$ 433.2	$ 297.9
Unallocated corporate expenses	(357.0)	(337.7)	(1,090.0)	(988.5)
Acquired deferred revenue adjustment	0.0	(0.7)	(0.3)	(4.0)
Amortization of acquired capitalized commissions	1.1	1.3	3.4	4.2
Amortization of purchased intangible assets	(34.3)	(40.0)	(105.1)	(120.2)
Acquisition / divestiture items	(0.2)	(3.7)	(10.3)	(16.4)
Stock-based compensation / deferred compensation	(32.1)	(32.0)	(99.1)	(61.9)
Restructuring and other costs	(1.7)	(14.7)	(7.9)	(26.7)
Total non-operating income (expense), net	9.2	(5.6)	23.3	(31.2)
Income before taxes	156.7	96.4	456.5	266.7
Operating segment
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Consolidated operating income	241.4	210.2	728.5	571.6
Non-Segment
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Unallocated corporate expenses	$ (26.7)	$ (18.4)	$ (76.0)	$ (48.7)

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