Receivables - Trade and Unbilled Receivables and Notes Receivable (Detail) - USD ($) $ in Millions	Oct. 02, 2020	Sep. 27, 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Trade and unbilled receivables, gross	$ 1,198.1	$ 1,193.5
Allowance for doubtful accounts	(58.3)	(46.5)
Trade and unbilled receivables, net	1,139.8	1,147.0
Short-term	1,066.1	1,106.3
Long-term	73.7	40.7
Notes Receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Long-term notes receivable	$ 36.7	$ 33.6