Intangible Assets and Goodwill - Schedule of Intangible Assets (Detail) - USD ($) $ in Millions	Jun. 27, 2020	Sep. 28, 2019
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	$ 4,798.7	$ 4,786.6
Accumulated Amortization	3,546.2	3,326.8
Developed technology
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	3,925.4	3,927.7
Accumulated Amortization	2,842.8	2,654.8
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	547.0	525.5
Accumulated Amortization	468.9	447.5
Trade names
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	244.1	245.4
Accumulated Amortization	178.6	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	1.2	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	4,720.3	4,704.8
Accumulated Amortization	3,493.7	3,276.5
Internal-use software
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	51.7	53.9
Accumulated Amortization	42.7	43.4
Capitalized software embedded in products
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	26.7	27.9
Accumulated Amortization	$ 9.8	$ 6.9