Intangible Assets and Goodwill - Schedule of Intangible Assets (Detail) - USD ($) $ in Millions	Dec. 28, 2019	Sep. 28, 2019
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	$ 4,764.0	$ 4,786.6
Accumulated Amortization	3,397.0	3,326.8
Developed technology
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	3,909.3	3,927.7
Accumulated Amortization	2,716.7	2,654.8
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	527.7	525.5
Accumulated Amortization	454.5	447.5
Trade names
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	244.7	245.4
Accumulated Amortization	173.6	171.1
Distribution agreement
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	0.0	2.5
Accumulated Amortization	0.0	0.0
Non-competition agreements
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	1.5	1.4
Accumulated Amortization	1.0	0.9
Business licenses
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	2.3	2.3
Accumulated Amortization	2.2	2.2
Total acquired intangible assets
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	4,685.5	4,704.8
Accumulated Amortization	3,348.0	3,276.5
Internal-use software
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	50.8	53.9
Accumulated Amortization	40.9	43.4
Capitalized software embedded in products
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	27.7	27.9
Accumulated Amortization	$ 8.1	$ 6.9