Borrowings and Credit Arrangements - Company's Borrowings (Detail) - USD ($) $ in Millions	Dec. 25, 2021	Sep. 25, 2021
Debt Instrument [Line Items]
Current portion of long-term debt	$ 248.7	$ 313.0
Total long-term debt obligations	2,819.6	2,712.2
Total debt obligations	3,068.3	3,025.2
Term Loan
Debt Instrument [Line Items]
Long term debt obligations. excluding convertible notes	1,489.1	1,382.3
Accounts Receivable Securitization
Debt Instrument [Line Items]
Current portion of long-term debt	248.5	248.5
Other Debt Obligations
Debt Instrument [Line Items]
Current portion of long-term debt	0.2	64.5
2028 Senior Notes
Debt Instrument [Line Items]
Long term debt obligations. excluding convertible notes	395.5	395.4
2029 Senior Notes
Debt Instrument [Line Items]
Long term debt obligations. excluding convertible notes	$ 935.0	$ 934.5

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