Borrowings and Credit Arrangements - Company's Borrowings (Detail) $ in Millions	3 Months Ended
Dec. 30, 2017 USD ($)	Sep. 30, 2017 USD ($)
Debt Instrument [Line Items]
Current portion of long-term debt	$ 572.1	$ 1,150.8
Convertible Notes	205.4	484.5
Total long-term debt obligations	2,757.7	2,172.1
Total debt obligations	$ 3,329.8	3,322.9
Amended Credit Agreement [Member]
Debt Instrument [Line Items]
Debt Instrument, Number of Fiscal Quarters Ending on Measurement Date	4
Term Loan [Member]
Debt Instrument [Line Items]
Current portion of long-term debt	$ 46.7	121.3
Long term debt obligations. excluding convertible notes	1,430.1	1,190.5
Revolver [Member]
Debt Instrument [Line Items]
Current portion of long-term debt	120.0	345.0
Accounts Receivable Securitization [Member]
Debt Instrument [Line Items]
Current portion of long-term debt	200.0	200.0
2022 Notes
Debt Instrument [Line Items]
Long term debt obligations. excluding convertible notes	982.6	981.6
2025 Senior Notes
Debt Instrument [Line Items]
Long term debt obligations. excluding convertible notes	$ 345.0	$ 0.0

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Long term debt obligations without convertible notes.

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+ References

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-Publisher FASB
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