Schedule II - Valuation and Qualifying Accounts (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 27, 2019	Dec. 28, 2018	Dec. 29, 2017
Allowance for doubtful accounts
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	$ 5.0	$ 3.9	$ 4.0
Charged to Operations	1.5	3.8	0.6
Additions and Other	0.0	0.0	0.0
Deductions	(2.5)	(2.7)	(0.7)
Balance at End of Period	4.0	5.0	3.9
Sales Returns and Allowances
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	405.4	376.6	391.3
Charged to Operations	2,437.7	2,387.5	2,008.5
Additions and Other	0.0	0.0	0.0
Deductions	(2,505.7)	(2,358.7)	(2,023.2)
Balance at End of Period	337.4	405.4	376.6
Tax valuation allowance
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	2,604.9	2,267.9	1,398.3
Charged to Operations	526.6	332.8	804.6
Additions and Other	0.0	4.2	4.0
Deductions	0.0	0.0	(61.0)
Balance at End of Period	$ 3,131.5	$ 2,604.9	$ 2,267.9