Goodwill and Intangible Assets, Net - Amortization of 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]
Amortization of intangible assets	$ 161.2	$ 96.5	$ 92.8
Completed technology
Goodwill and Intangible Assets Disclosure [Line Items]
Amortization of intangible assets	108.7	50.4	43.9
Customer relationships
Goodwill and Intangible Assets Disclosure [Line Items]
Amortization of intangible assets	46.5	44.6	45.0
Backlog, trade name and other
Goodwill and Intangible Assets Disclosure [Line Items]
Amortization of intangible assets	$ 6.0	$ 1.5	$ 3.9