Income taxes - Summary of Income and Income Taxes (Details) - USD ($) $ in Millions	12 Months Ended
	Jan. 30, 2021	Feb. 01, 2020	Feb. 02, 2019
Income (loss) before income taxes:
– US	$ (173.4)	$ 32.3	$ (1,135.8)
– Foreign	83.7	97.4	333.2
Income (loss) before income taxes	(89.7)	129.7	(802.6)
Current taxation:
– US	(222.2)	3.0	(55.2)
– Foreign	0.7	1.9	15.8
Deferred taxation:
– US	158.4	17.0	(85.8)
– Foreign	(11.4)	2.3	(20.0)
Total income tax expense (benefit)	$ (74.5)	$ 24.2	$ (145.2)