Goodwill and Intangible Assets (Schedule Of Intangible Assets Subject To Amortization) (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 27, 2019	Sep. 27, 2019
Finite-Lived Intangible Assets [Line Items]
Accumulated Amortization	$ (78.5)	$ (74.5)
Total intangible assets, Gross Carrying Amount	175.0	182.4
Total intangible assets, Net Carrying Amount	$ 96.5	107.9
Customer relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Weighted Average Amortization Period (Years)	5 years
Finite-Lived Intangible Assets, Gross	$ 18.2	25.6
Accumulated Amortization	(13.0)	(19.5)
Net Carrying Amount	$ 5.2	6.1
Technology-Based Intangible Assets [Member]
Finite-Lived Intangible Assets [Line Items]
Weighted Average Amortization Period (Years)	4 years 1 month 6 days
Finite-Lived Intangible Assets, Gross	$ 94.4	94.4
Accumulated Amortization	(56.9)	(48.9)
Net Carrying Amount	$ 37.5	45.5
Trade Names [Member]
Finite-Lived Intangible Assets [Line Items]
Weighted Average Amortization Period (Years)	3 years
Finite-Lived Intangible Assets, Gross	$ 1.6	1.6
Accumulated Amortization	(1.5)	(1.3)
Net Carrying Amount	$ 0.1	0.3
Computer Software, Intangible Asset [Member]
Finite-Lived Intangible Assets [Line Items]
Weighted Average Amortization Period (Years)	3 years 1 month 6 days
Finite-Lived Intangible Assets, Gross	$ 24.9	24.9
Accumulated Amortization	(7.1)	(4.8)
Net Carrying Amount	$ 17.8	20.1
In Process Research and Development [Member]
Finite-Lived Intangible Assets [Line Items]
Weighted Average Amortization Period (Years)	0 years
Finite-Lived Intangible Assets, Gross	$ 35.9	35.9
Accumulated Amortization	0.0	0.0
Net Carrying Amount	$ 35.9	$ 35.9