Borrowings and Credit Arrangements - Company's Borrowings (Detail) (USD $)	Mar. 28, 2015	Sep. 27, 2014
Debt Instrument [Line Items]
Current debt obligations, net of debt discount	$ 581,700,000us-gaap_LongTermDebtCurrent	$ 114,500,000us-gaap_LongTermDebtCurrent
Convertible Notes Payable, Current	417,300,000us-gaap_ConvertibleNotesPayableCurrent	0us-gaap_ConvertibleNotesPayableCurrent
Convertible Notes	844,000,000us-gaap_ConvertibleLongTermNotesPayable	1,235,600,000us-gaap_ConvertibleLongTermNotesPayable
Total long-term debt obligations	3,358,100,000us-gaap_LongTermDebtNoncurrent	4,153,200,000us-gaap_LongTermDebtNoncurrent
Total debt obligations	3,939,800,000us-gaap_LongTermDebt	4,267,700,000us-gaap_LongTermDebt
Term Loan A
Debt Instrument [Line Items]
Current debt obligations, net of debt discount	149,500,000	99,600,000
Long-term debt obligations, net of debt discount	697,600,000	796,700,000
Term Loan B
Debt Instrument [Line Items]
Current debt obligations, net of debt discount	14,900,000	14,900,000
Long-term debt obligations, net of debt discount	816,500,000	1,120,900,000
Senior Notes
Debt Instrument [Line Items]
Long-term debt obligations, net of debt discount	$ 1,000,000,000	$ 1,000,000,000

Long term debt obligations without convertible notes.

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Carrying value as of the balance sheet date of long-term debt (with maturities initially due after one year or beyond the operating cycle if longer) identified as Convertible Notes Payable, excluding current portion. Convertible Notes Payable is a written promise to pay a note which can be exchanged for a specified amount of another, related security, at the option of the issuer and the holder.

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Carrying value as of the balance sheet date of the portion of long-term debt due within one year or the operating cycle if longer identified as Convertible Notes Payable. Convertible Notes Payable is a written promise to pay a note which can be exchanged for a specified amount of another, related security, at the option of the issuer and the holder.

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Carrying amount of long-term debt, net of unamortized discount or premium, including current and noncurrent amounts. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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Amount of long-term debt, after unamortized discount or premium, scheduled to be repaid within one year or the normal operating cycle, if longer. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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