(Schedule of Carrying Amount and Fair Value of Long-term Debt) (Details) - USD ($) $ in Millions	Dec. 27, 2019	Dec. 28, 2018	Feb. 13, 2018
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long term debt	$ 3,840.8	$ 5,269.1
Long-term Debt, Current Maturities	634.5	22.7
Long-term Debt, Gross	4,788.3	6,134.0
Debt, Long-term and Short-term, Combined Amount	5,422.8	6,156.7
4.00% term loan due February 2022
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loan payable		2.2
Loans Payable		2.2
Other Loan
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loan payable	0.0
Loans Payable	0.0
Secured Debt | Receivable securitization, Maturity Date of July 2020 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt, Gross		250.0
Debt, Long-term and Short-term, Combined Amount	0.0	250.0
Secured Debt | Term Loan due 2025 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loan payable	326.2	548.0
Long-term Debt, Current Maturities	4.1	6.0
Loans Payable	403.6	597.0
Long-term Debt, Gross	399.5	591.0
Secured Debt | Term Loan due Sept 2024 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loan payable	1,240.0	1,472.4
Long-term Debt, Current Maturities	15.6	16.4
Loans Payable	1,520.8	1,613.8
Long-term Debt, Gross	1,505.2	1,597.4
Debentures | 9.50% debentures due May 2022
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long term debt	5.4	9.7
Long-term Debt, Gross		10.4
Debt, Long-term and Short-term, Combined Amount	10.4	10.4
Debentures | 8.00% debentures due March 2023
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long term debt	2.0	3.8
Long-term Debt, Gross		4.4
Debt, Long-term and Short-term, Combined Amount	4.4	4.4
Senior Notes | 5.75% senior notes due August 2022
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long term debt	251.0	713.6
Long-term Debt, Gross		835.2
Debt, Long-term and Short-term, Combined Amount	610.3	835.2
Senior Notes | 4.75% senior notes due April 2023
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long term debt	53.7	336.7
Long-term Debt, Gross		500.2
Debt, Long-term and Short-term, Combined Amount	133.7	500.2
Debentures | Four Point Eight Eight Percent Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long term debt	480.0	676.6
Long-term Debt, Current Maturities	614.8	0.0
Long-term Debt, Gross	0.0	700.0
Debt, Long-term and Short-term, Combined Amount	614.8	700.0
Debentures | Five Point Five Percent Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long term debt	135.5	479.1
Long-term Debt, Gross		692.1
Debt, Long-term and Short-term, Combined Amount	387.2	692.1
Debentures | Ten Point Zero Percent Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long term debt	253.8	0.0
Long-term Debt, Gross		0.0
Debt, Long-term and Short-term, Combined Amount	322.9	0.0
Debentures | 2017 Revolving Credit Facility
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long term debt	900.0	220.0
Long-term Debt, Gross		220.0	$ 900.0
Debt, Long-term and Short-term, Combined Amount	900.0	220.0
Debentures | Five Point Six Two Five Percent Note
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long term debt	193.2	557.0
Long-term Debt, Gross		731.4
Debt, Long-term and Short-term, Combined Amount	514.7	731.4
Debentures | Other Loan
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt, Current Maturities	0.0	0.3
Long-term Debt, Gross	0.0	1.9
Fair Value | Receivable securitization, Maturity Date of July 2020 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt, Gross	$ 0.0	$ 250.0