Segment information - Reconciliation of Adjusted EBITDA to Net Income (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 26, 2020	Sep. 28, 2019	Sep. 26, 2020	Sep. 28, 2019
Segment Reporting Information
Net income from continuing operations	$ 45.7	$ 37.5	$ 57.8	$ 669.3
Income tax (benefit) expense	(16.0)	4.4	(31.5)	(497.8)
Income from continuing operations before taxes	29.7	41.9	26.3	171.5
Interest expense	38.3	37.2	109.3	114.5
Other income	(4.1)	(2.4)	(9.9)	(7.2)
Operating income from continuing operations	63.9	76.7	125.7	278.8
Depreciation and amortization	53.6	55.1	163.2	167.4
Transaction-related expenses	5.4	1.0	5.2	0.7
Asset impairments	1.4	0.7	5.1	0.7
Restructuring expenses	7.3	0.3	26.4	3.9
Share-based compensation expense	4.9	4.1	13.5	10.5
Sponsor fees (included in other operating expenses)	0.2	1.1	1.9	4.9
Inventory impairments (included in cost of sales)	0.0	1.0	1.4	1.3
Other items not directly related to current operations	0.0	0.7	(3.1)	1.7
Adjusted EBITDA	140.0	145.0	344.0	475.9
Cost of sales
Segment Reporting Information
Severance expenses (included in cost of sales)	0.3	2.5	0.9	3.0
SG&A
Segment Reporting Information
Severance expenses (included in SG&A)	$ 3.0	$ 1.8	$ 3.8	$ 3.0