Debt (Schedule of Long-term Debt including Capital Lease Obligation) (Details) - USD ($) $ in Millions	Mar. 25, 2016	Sep. 25, 2015
Long-term Debt, Current Maturities [Abstract]
Capital Lease Obligations, Current	$ 1.0	$ 1.3
Unamortized Debt Issuance Fees and Discount, Current	0.4	0.0
Long-term Debt, Current Maturities	22.0	22.3
Long-term Debt, Excluding Current Maturities [Abstract]
Total debt	6,531.3	6,606.5
Capital Lease Obligations, Noncurrent	0.6	1.0
Long-term Debt, Gross	6,509.3	6,584.2
Unamortized Debt Issuance Expense and Discount	100.1	109.9
Variable Rate Receivable Securitization	215.0	153.0
Capital Lease Obligations and Vendor Financing
Long-term Debt, Excluding Current Maturities [Abstract]
Unamortized Debt Issuance Expense and Discount	0.0	0.0
2015 Revolving Credit Facility
Long-term Debt, Excluding Current Maturities [Abstract]
Unamortized Debt Issuance Expense and Discount	4.3	4.9
Long-term Debt
Long-term Debt, Excluding Current Maturities [Abstract]
Unamortized Debt Issuance Expense and Discount	99.7	109.9
Term Loan and New Term Loan | Secured Debt
Long-term Debt, Current Maturities [Abstract]
Unamortized Debt Issuance Fees and Discount, Current	0.4	0.0
Long-term Debt, Current Maturities	20.0	20.0
Long-term Debt, Excluding Current Maturities [Abstract]
Total debt	1,968.5
Long-term Debt, Gross	1,948.5	1,958.5
Unamortized Debt Issuance Expense and Discount	39.6	44.1
4.00% Term Loan | Secured Debt
Long-term Debt, Current Maturities [Abstract]
Unamortized Debt Issuance Fees and Discount, Current	0.0	0.0
Long-term Debt, Current Maturities	1.0	1.0
Long-term Debt, Excluding Current Maturities [Abstract]
Long-term Debt, Gross	6.4	6.9
Unamortized Debt Issuance Expense and Discount	0.0	0.0
Capital Lease Obligations and Vendor Financing
Long-term Debt, Current Maturities [Abstract]
Unamortized Debt Issuance Fees and Discount, Current	0.0	0.0
Receivable Securitization
Long-term Debt, Excluding Current Maturities [Abstract]
Unamortized Debt Issuance Expense and Discount	0.7	0.8
3.50% Senior Notes | Senior Notes
Long-term Debt, Excluding Current Maturities [Abstract]
Long-term Debt, Gross	300.0	300.0
Unamortized Debt Issuance Expense and Discount	1.4	1.7
4.88% Senior Notes | Unsecured Debt
Long-term Debt, Excluding Current Maturities [Abstract]
Long-term Debt, Gross	700.0	700.0
2020 Notes | Senior Notes
Long-term Debt, Excluding Current Maturities [Abstract]
Unamortized Debt Issuance Expense and Discount	10.0	11.3
9.50% Debenture | Debentures
Long-term Debt, Excluding Current Maturities [Abstract]
Long-term Debt, Gross	10.4	10.4
Unamortized Debt Issuance Expense and Discount	0.0	0.0
5.75% Senior Notes | Senior Notes
Long-term Debt, Excluding Current Maturities [Abstract]
Long-term Debt, Gross	884.0	900.0
Unamortized Debt Issuance Expense and Discount	13.1	14.4
8.00% Debenture | Debentures
Long-term Debt, Excluding Current Maturities [Abstract]
Long-term Debt, Gross	4.4	4.4
Unamortized Debt Issuance Expense and Discount	0.0	0.0
4.75% Senior Notes | Senior Notes
Long-term Debt, Excluding Current Maturities [Abstract]
Long-term Debt, Gross	600.0	600.0
Unamortized Debt Issuance Expense and Discount	6.7	7.1
5.625% Senior Notes | Senior Notes
Long-term Debt, Excluding Current Maturities [Abstract]
Unamortized Debt Issuance Expense and Discount	12.7	13.7
5.625% Senior Notes | Unsecured Debt
Long-term Debt, Excluding Current Maturities [Abstract]
Long-term Debt, Gross	740.0	750.0
5.50% Senior Notes | Unsecured Debt
Long-term Debt, Excluding Current Maturities [Abstract]
Long-term Debt, Gross	700.0	700.0
2025 Notes | Senior Notes
Long-term Debt, Excluding Current Maturities [Abstract]
Unamortized Debt Issuance Expense and Discount	11.2	11.9
2015 Revolving Credit Facility | Unsecured Debt
Long-term Debt, Excluding Current Maturities [Abstract]
Long-term Debt, Gross	$ 400.0	$ 500.0