Restructuring and other charges - Narrative (Details) $ in Millions	12 Months Ended
	Dec. 28, 2025 USD ($) employee	Dec. 29, 2024 USD ($) employee	Dec. 31, 2023 USD ($) employee	Jan. 01, 2023 USD ($)
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 48.8	$ 22.1	$ 31.4
Restructuring (credits) charges	$ (1.9)	$ 4.1	$ 7.7
Restructuring and related cost, expected number of positions eliminated | employee	45	100	110
Restructuring Charges, Statement of Income or Comprehensive Income [Extensible Enumeration]	Cost of sales, Selling and administrative expenses	Cost of sales, Selling and administrative expenses	Cost of sales, Restructuring (credits) charges
Cost of Sales
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 23.6	$ 15.3	$ 23.7
Restructuring Charges, Statement of Income or Comprehensive Income [Extensible Enumeration]	Cost of sales	Cost of sales	Cost of sales
Selling, General and Administrative Expenses
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 27.1	$ 2.7
Restructuring Charges, Statement of Income or Comprehensive Income [Extensible Enumeration]	Selling and administrative expenses	Selling and administrative expenses
Restructuring, Settlement And Impairment Provisions, Excluding Goodwill Impairment Loss
Restructuring Cost and Reserve [Line Items]
Restructuring charges			$ 7.7
Restructuring Charges, Statement of Income or Comprehensive Income [Extensible Enumeration]			Restructuring (credits) charges
Start Up Costs
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 25.8	$ 13.4	$ 11.5
Transformation Costs
Restructuring Cost and Reserve [Line Items]
Restructuring charges	17.1
Losses on the Sale of Customer Accounts Receivable
Restructuring Cost and Reserve [Line Items]
Restructuring charges	7.8
Inventory Write-offs
Restructuring Cost and Reserve [Line Items]
Restructuring charges		4.6
Unplanned Outage Costs
Restructuring Cost and Reserve [Line Items]
Restructuring charges			1.9
Asset Write-offs
Restructuring Cost and Reserve [Line Items]
Restructuring charges			10.3
Employee Severance
Restructuring Cost and Reserve [Line Items]
Restructuring (credits) charges	(1.9)	4.1	7.7
Divestitures	0.5	3.5	0.0
Restructuring reserve	$ 0.4	$ 9.0	$ 15.2	$ 9.8