Acquisitions (Fair Values Of The Assets Acquired And Liabilities) (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 28, 2018	Sep. 29, 2017
Business Acquisition [Line Items]
Trade accounts receivable	$ 41.3
Inventories	15.1
Property, plant and equipment	89.0
Goodwill	1,310.4
Other intangible assets, primarily customer relationships, trade names and technology	789.0
Trade accounts payable	(8.2)
Other assets and liabilities, net	(39.4)
Net assets acquired	2,197.2
Less: noncash consideration	(23.9)
Net cash consideration	2,173.3	$ 112.0
IDT
Business Acquisition [Line Items]
Trade accounts receivable	36.0
Inventories	15.1
Property, plant and equipment	88.6
Goodwill	1,239.9
Other intangible assets, primarily customer relationships, trade names and technology	759.0
Trade accounts payable	(5.5)
Other assets and liabilities, net	(31.0)
Net assets acquired	2,102.1
Less: noncash consideration	(23.9)
Net cash consideration	2,078.2
Series of individually immaterial business acquisitions
Business Acquisition [Line Items]
Trade accounts receivable	5.3
Inventories	0.0
Property, plant and equipment	0.4
Goodwill	70.5
Other intangible assets, primarily customer relationships, trade names and technology	30.0
Trade accounts payable	(2.7)
Other assets and liabilities, net	(8.4)
Net assets acquired	95.1
Less: noncash consideration	0.0
Net cash consideration	$ 95.1