Fair Value - Reconciliation for Assets and Liabilities Measured and Recorded at Fair Value on Recurring Basis (Detail) - Fair Value, Measurements, Recurring - Contingent Consideration - USD ($) $ in Millions	12 Months Ended
	Oct. 02, 2020	Sep. 27, 2019
Contingent Consideration
Beginning Balance	$ (75.3)	$ (24.4)
Additions	(8.9)	(45.4)
Measurement period adjustment to a business combination in prior year		11.6
Foreign exchange	0.6	0.5
Settlements	41.4	1.0
Change in fair value recognized in earnings	(0.3)	(18.6)
Ending Balance	$ (43.1)	$ (75.3)