Retirement plans - Components of Net Periodic Pension Cost (Details) - Pension plan - Foreign Plan - USD ($) $ in Millions	3 Months Ended				12 Months Ended
	Apr. 29, 2023	Jan. 28, 2023	Jul. 30, 2022	Apr. 30, 2022	Feb. 03, 2024	Jan. 28, 2023
Defined Benefit Plan Disclosure [Line Items]
Interest cost					$ 0.0	$ (1.0)
Expected return on UK Plan assets					(2.5)	(0.3)
Amortization of unrecognized actuarial losses					0.0	(3.5)
Amortization of unrecognized net prior service costs					0.0	(0.3)
Pension settlement loss	$ (0.2)	$ (0.9)	$ (0.9)	$ (131.9)	(0.2)	(133.7)
Total net periodic benefit cost					(2.7)	(138.8)
Other changes in assets and benefit obligations recognized in OCI					0.2	137.0
Total recognized in net periodic pension benefit cost and OCI					$ (2.5)	$ (1.8)