Goodwill and Intangible Assets (Schedule Of Intangible Assets Subject To Amortization) (Details) - USD ($) $ in Millions	6 Months Ended
	Apr. 01, 2022	Oct. 01, 2021
Finite-Lived Intangible Assets [Line Items]
Accumulated Amortization	$ (232.6)	$ (155.9)
Total intangible assets, Gross Carrying Amount	1,798.3	1,854.5
Total intangible assets, Net Carrying Amount	$ 1,565.7	1,698.6
Customer relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Weighted Average Amortization Period (Years)	2 years 3 months 18 days
Finite-Lived Intangible Assets, Gross	$ 154.6	174.3
Accumulated Amortization	(79.0)	(44.0)
Net Carrying Amount	$ 75.6	130.3
Computer Software, Intangible Asset [Member]
Finite-Lived Intangible Assets [Line Items]
Weighted Average Amortization Period (Years)	2 years 7 months 6 days
Finite-Lived Intangible Assets, Gross	$ 61.4	48.4
Accumulated Amortization	(32.7)	(23.9)
Net Carrying Amount	28.7	24.5
In Process Research and Development [Member]
Finite-Lived Intangible Assets [Line Items]
Accumulated Amortization	0.0	0.0
Indefinite-lived Intangible Assets (Excluding Goodwill)	$ 427.7	594.9
Developed Technology Rights
Finite-Lived Intangible Assets [Line Items]
Weighted Average Amortization Period (Years)	4 years 1 month 6 days
Finite-Lived Intangible Assets, Gross	$ 1,154.6	1,036.9
Accumulated Amortization	(120.9)	(88.0)
Net Carrying Amount	$ 1,033.7	$ 948.9
Developed Technology Rights | Silicon Labs Industrial and Automotive Business
Finite-Lived Intangible Assets [Line Items]
Weighted Average Amortization Period (Years)	6 years 7 months 6 days