Borrowings and Credit Arrangements - Company's Borrowings (Detail) - USD ($) $ in Millions	Jun. 29, 2019	Sep. 29, 2018
Debt Instrument [Line Items]
Current portion of long-term debt	$ 262.0	$ 599.7
Total long-term debt obligations	2,791.6	2,704.6
Total debt obligations	3,053.6	3,304.3
Term Loan
Debt Instrument [Line Items]
Current portion of long-term debt	28.0	74.7
Long term debt obligations. excluding convertible notes	1,461.2	1,376.3
Revolver
Debt Instrument [Line Items]
Current portion of long-term debt	0.0	300.0
Securitization Program
Debt Instrument [Line Items]
Current portion of long-term debt	234.0	225.0
2025 Senior Notes
Debt Instrument [Line Items]
Long term debt obligations. excluding convertible notes	936.7	935.2
2028 Senior Notes
Debt Instrument [Line Items]
Long term debt obligations. excluding convertible notes	$ 393.7	$ 393.1

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