Segment Information (Reconciliation Of Company's Consolidated Segment Operating Income To Consolidated Income Before Income Taxes) (Detail) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 28, 2019	Jun. 29, 2018	Jun. 28, 2019	Jun. 29, 2018
Segment Reporting Information [Line Items]
Consolidated operating income	$ 109.7	$ 89.5	$ 196.0	$ 153.7
Unallocated corporate expense	(350.9)	(333.2)	(702.9)	(665.2)
Restructuring charges	(2.9)	(2.8)	(6.6)	(4.2)
Acquired deferred revenue adjustment	(1.0)	(3.8)	(3.9)	(6.7)
Amortization of purchased intangible assets	(43.5)	(42.6)	(87.8)	(83.1)
Stock-based compensation	(17.2)	(16.9)	(33.5)	(34.3)
Amortization of acquired capitalized commissions	1.6	0.6	3.3	1.1
Acquisition / divestiture items	(2.0)	(8.1)	(3.1)	(24.1)
Non-operating income (expense), net	5.7	(10.3)	(5.4)	(7.8)
Consolidated income before taxes	115.4	79.2	190.6	145.9
Operating Segments [Member]
Segment Reporting Information [Line Items]
Consolidated operating income	194.1	185.6	368.3	350.9
Corporate, Non-Segment [Member]
Segment Reporting Information [Line Items]
Unallocated corporate expense	$ (19.4)	$ (22.5)	$ (40.7)	$ (45.9)

The aggregate amount of recurring noncash expense charged against earnings in the period to allocate the cost of assets over their estimated remaining economic lives.

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The amount of expense recognized in the current period for the periodic realization of capitalized fees that were paid to salespeople, distributors, brokers, and agents at the time of the conclusion of the sale. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method.

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This element represents acquisition-related costs incurred to effect a business combination which costs have been expensed during the period. Such costs include finder's fees; advisory, legal, accounting, valuation, and other professional or consulting fees; general administrative costs, including the costs of maintaining an internal acquisitions department; and may include costs of registering and issuing debt and equity securities.

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Amount of increase (decrease) in obligation to transfer good or service to customer for which consideration from customer has been received or is due, from business combination.

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Amount of income (loss) from continuing operations before deduction of income tax expense (benefit) and income (loss) attributable to noncontrolling interest, and addition of income (loss) from equity method investments.

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The aggregate amount of income or expense from ancillary business-related activities (that is to say, excluding major activities considered part of the normal operations of the business).

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Generally recurring costs associated with normal operations except for the portion of these expenses which can be clearly related to production and included in cost of sales or services. Includes selling, general and administrative expense.

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Amount, after cash payment, of expenses associated with exit or disposal activities pursuant to an authorized plan. Excludes expenses related to a discontinued operation or an asset retirement obligation.

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The aggregate amount of noncash, equity-based employee remuneration. This may include the value of stock or unit options, amortization of restricted stock or units, and adjustment for officers' compensation. As noncash, this element is an add back when calculating net cash generated by operating activities using the indirect method.

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