Stockholders' Equity and Noncontrolling Interests - Schedule of Amounts Reclassified Out of Other Comprehensive Earnings (Detail) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Oct. 02, 2020	Jul. 03, 2020	Apr. 03, 2020	Jan. 03, 2020	Sep. 27, 2019	Jun. 28, 2019	Mar. 29, 2019	Dec. 28, 2018	Oct. 02, 2020	Sep. 27, 2019	Sep. 28, 2018
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income On Derivatives [Line Items]
Other income, net									$ 38.7	$ 28.3	$ 4.2
Revenues	$ 850.5	$ 694.3	$ 794.5	$ 828.9	$ 878.9	$ 825.8	$ 779.4	$ 741.0	3,168.2	3,225.1	2,919.1
Operating earnings									323.2	386.2	437.4
Net Unrealized Gains (Losses) Defined Benefit Pension and Post-Retirement Benefit Plans
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income On Derivatives [Line Items]
Other income, net									(3.2)	(1.5)	(1.7)
Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income On Derivatives [Line Items]
Operating earnings									(0.6)	(1.3)	(2.6)
Reclassification out of Accumulated Other Comprehensive Income | Net Unrealized Gains (Losses) Cash Flow Hedging Instruments
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income On Derivatives [Line Items]
Revenues									$ 2.6	$ 0.2	$ (0.9)