(Schedule of Carrying Amount and Fair Value of Long-term Debt) (Details) - USD ($) $ in Millions	Sep. 25, 2015	Sep. 26, 2014
Carrying Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Variable rate receivable securitization	$ 153.0	$ 150.0
Carrying Value | 2.85% term loan due April 2016
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loan payable	0.0	3.1
Carrying Value | Term loan due March 2021
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loan payable	1,978.5	1,996.7
Carrying Value | 4.00% term loan due February 2022
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loan payable	7.9	10.8
Carrying Value | Debentures | 9.50% debentures due May 2022
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long term debt	10.4	10.4
Carrying Value | Debentures | 8.00% debentures due March 2023
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long term debt	4.4	8.0
Carrying Value | Senior Notes | 3.50% notes due April 2018
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long term debt	300.0	300.0
Carrying Value | Senior Notes | 5.75% notes due August 2022
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long term debt	900.0	900.0
Carrying Value | Senior Notes | 4.75% notes due April 2023
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long term debt	600.0	600.0
Carrying Value | Debentures | Four Point Eight Eight Percent Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long term debt	700.0	0.0
Carrying Value | Debentures | Five Point Five Percent Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long term debt	700.0	0.0
Carrying Value | Debentures | 2015 Revolving Credit Facility
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long term debt	500.0
Carrying Value | Debentures | 5.625% notes due October 2023
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long term debt	750.0	0.0
Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Variable rate receivable securitization	153.0	150.0
Fair Value | 2.85% term loan due April 2016
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loan payable	0.0	3.1
Fair Value | Term loan due March 2021
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loan payable	1,966.5	1,970.4
Fair Value | 4.00% term loan due February 2022
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loan payable	7.9	10.8
Fair Value | Debentures | 9.50% debentures due May 2022
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long term debt	13.0	14.2
Fair Value | Debentures | 8.00% debentures due March 2023
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long term debt	5.3	10.2
Fair Value | Senior Notes | 3.50% notes due April 2018
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long term debt	294.3	290.2
Fair Value | Senior Notes | 5.75% notes due August 2022
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long term debt	876.1	907.3
Fair Value | Senior Notes | 4.75% notes due April 2023
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long term debt	539.6	563.8
Fair Value | Debentures | Four Point Eight Eight Percent Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long term debt	684.1	0.0
Fair Value | Debentures | Five Point Five Percent Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long term debt	646.0	0.0
Fair Value | Debentures | 2015 Revolving Credit Facility
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long term debt	500.0
Fair Value | Debentures | 5.625% notes due October 2023
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long term debt	$ 705.2	$ 0.0