Goodwill and Intangible Assets, Net - Goodwill and Intangible Assets (Detail) - USD ($) $ in Millions	12 Months Ended
	Oct. 02, 2016	Sep. 27, 2015	Sep. 28, 2014
Goodwill and Intangible Assets Disclosure [Line Items]
Gross Carrying Value	$ 1,270.6	$ 824.7
Accumulated Amortization	(577.0)	(466.9)
Goodwill	2,479.4	1,139.3	$ 885.6
Completed technology
Goodwill and Intangible Assets Disclosure [Line Items]
Gross Carrying Value	907.7	489.7
Accumulated Amortization	(335.1)	(251.7)
Customer relationships
Goodwill and Intangible Assets Disclosure [Line Items]
Gross Carrying Value	338.0	316.2
Accumulated Amortization	(219.2)	(197.1)
Backlog, trade name and other
Goodwill and Intangible Assets Disclosure [Line Items]
Gross Carrying Value	24.9	18.8
Accumulated Amortization	$ (22.7)	(18.1)
Minimum | Completed technology
Goodwill and Intangible Assets Disclosure [Line Items]
Life (years)	2 years
Minimum | Customer relationships
Goodwill and Intangible Assets Disclosure [Line Items]
Life (years)	4 years
Minimum | Backlog, trade name and other
Goodwill and Intangible Assets Disclosure [Line Items]
Life (years)	1 year
Maximum | Completed technology
Goodwill and Intangible Assets Disclosure [Line Items]
Life (years)	15 years
Maximum | Customer relationships
Goodwill and Intangible Assets Disclosure [Line Items]
Life (years)	15 years
Maximum | Backlog, trade name and other
Goodwill and Intangible Assets Disclosure [Line Items]
Life (years)	5 years
In Process Research and Development [Member]
Goodwill and Intangible Assets Disclosure [Line Items]
Indefinite-Lived Intangible Assets (Excluding Goodwill)	$ 241.0	$ 0.0