Financial Instruments and Fair Value Measurements (Schedule of Carrying Amount and Fair Value of Long-term Debt) (Details) - USD ($) $ in Millions	Jun. 26, 2015	Sep. 26, 2014	Aug. 13, 2014	Apr. 30, 2013
Senior Notes | 3.50% Senior Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Stated interest rate				3.50%
Senior Notes | 5.75% Senior Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Stated interest rate			5.75%
Senior Notes | 4.75% Senior Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Stated interest rate				4.75%
Carrying Value | Secured Debt | Receivable Securitization
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long term debt	$ 153.0	$ 150.0
Carrying Value | Secured Debt | 2.85% Term Loan
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long term debt	0.0	3.1
Carrying Value | Secured Debt | Term Loan and New Term Loan
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long term debt	1,977.8	1,990.3
Carrying Value | Secured Debt | 4.00% Term Loan
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long term debt	8.8	10.8
Carrying Value | Senior Notes | 3.50% Senior Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long term debt	300.0	300.0
Carrying Value | Senior Notes | 4.88% Senior Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long term debt	700.0	0.0
Carrying Value | Senior Notes | 5.75% Senior Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long term debt	900.0	900.0
Carrying Value | Senior Notes | 4.75% Senior Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long term debt	598.4	598.3
Carrying Value | Senior Notes | 5.50% Senior Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long term debt	700.0	0.0
Carrying Value | Debentures | 9.50% Debenture
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long term debt	10.4	10.4
Carrying Value | Debentures | 8.00% Debenture
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long term debt	4.4	8.0
Fair Value | Secured Debt | Receivable Securitization
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long term debt	153.0	150.0
Fair Value | Secured Debt | 2.85% Term Loan
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long term debt	0.0	3.1
Fair Value | Secured Debt | Term Loan and New Term Loan
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long term debt	1,977.2	1,970.4
Fair Value | Secured Debt | 4.00% Term Loan
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long term debt	8.8	10.8
Fair Value | Senior Notes | 3.50% Senior Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long term debt	301.5	290.2
Fair Value | Senior Notes | 4.88% Senior Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long term debt	715.0	0.0
Fair Value | Senior Notes | 5.75% Senior Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long term debt	927.8	907.3
Fair Value | Senior Notes | 4.75% Senior Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long term debt	563.5	563.8
Fair Value | Senior Notes | 5.50% Senior Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long term debt	683.7	0.0
Fair Value | Debentures | 9.50% Debenture
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long term debt	13.1	14.2
Fair Value | Debentures | 8.00% Debenture
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long term debt	$ 5.3	$ 10.2
Level 1 | Senior Notes | 3.50% Senior Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Stated interest rate	3.50%
Level 1 | Senior Notes | 4.88% Senior Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Stated interest rate	4.875%
Level 1 | Senior Notes | 5.75% Senior Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Stated interest rate	5.75%
Level 1 | Senior Notes | 4.75% Senior Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Stated interest rate	4.75%
Level 1 | Senior Notes | 5.50% Senior Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Stated interest rate	5.50%