Income taxes - Narrative (Details) - USD ($) $ in Millions		12 Months Ended
	Dec. 27, 2023	Feb. 01, 2025	Feb. 03, 2024	Jan. 28, 2023	Jan. 29, 2022
Operating Loss Carryforwards [Line Items]
Statutory tax rate (percent)		21.00%	21.00%	21.00%
Deferred Tax Assets, Bermuda economic transition adjustment		$ 263.3	$ 263.3
Amount of Bermuda deferred tax asset possibly recognizable due to two year limitation		52.7
Goodwill, Impairment Loss		272.5	0.0	$ 0.0
Income tax examination, increase (decrease) in liability from prior year			(20.5)	20.5
Other Tax Expense (Benefit)			13.5
Net operating loss carryforwards		58.1	66.0
Capital loss carryforwards		11.3	11.5
Decrease in valuation allowance		(3.4)
Unrecognized tax benefits		28.1	26.0	$ 85.9	$ 24.9
Accrued interest related to unrecognized tax benefits		15.8
Accrued penalties		0.8
Increase resulting from settlements with taxing authorities		40.7
Domestic Tax Jurisdiction
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards		34.4
Internal Revenue Service (IRS)
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards		22.3
Foreign Tax Jurisdiction
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards		23.7
Capital loss carryforwards		$ 11.3	$ 11.5
Bermuda
Operating Loss Carryforwards [Line Items]
Statutory tax rate (percent)	15.00%	0.00%