Derivative Instruments and Hedging Activities - Outstanding Foreign Currency Forward Contracts that Were Entered into to Hedge Balance Sheet Exposures (Detail) - Foreign Exchange Forward - Not Designated as Hedging Instrument - USD ($) $ in Millions	Sep. 27, 2019	Sep. 28, 2018
Notional Value Sold
Derivative [Line Items]
Notional Value	$ 385.0	$ 398.3
Notional Value Purchased
Derivative [Line Items]
Notional Value	$ 52.3	$ 70.3