Taxes on Earnings - Schedule of Changes in Unrecognized Tax Benefits (Detail) - USD ($) $ in Millions	12 Months Ended
	Oct. 02, 2020	Sep. 27, 2019	Sep. 28, 2018
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Unrecognized tax benefits balance–beginning of fiscal year	$ 49.8	$ 43.5	$ 42.7
Additions based on tax positions related to a prior year	6.5	0.2	1.1
Reductions based on tax positions related to a prior year	(10.8)	(0.8)	(3.0)
Additions based on tax positions related to the current year	6.1	13.2	14.8
Settlements	(2.2)	0.0	(2.8)
Reductions resulting from the expiration of the applicable statute of limitations	(6.5)	(6.3)	(9.3)
Unrecognized tax benefits balance–end of fiscal year	$ 42.9	$ 49.8	$ 43.5