Income taxes - Components of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Millions	Jan. 29, 2022	Jan. 30, 2021
Assets
Foreign property, plant and equipment	$ 7.1	$ 7.3
Revenue deferral	88.6	95.6
Derivative instruments		0.3
Lease liabilities	284.3	331.5
Deferred compensation	7.7	6.7
Retirement benefit obligations	1.5
Share-based compensation	8.4	4.4
Other temporary differences	42.4	57.2
Net operating losses and foreign tax credits	84.3	56.5
Value of capital losses	16.9	13.9
Total gross deferred tax assets (liabilities)	541.2	573.4
Valuation allowance	(27.9)	(83.9)
Deferred tax assets (liabilities)	513.3	489.5
(Liabilities)
Intangible assets	(77.0)	(41.7)
US property, plant and equipment	(60.2)	(55.3)
Inventory valuation	(237.8)	(230.4)
Lease assets	(261.9)	(295.1)
Retirement benefit obligations		(9.8)
Total gross deferred tax assets (liabilities)	(636.9)	(632.3)
Total
Total gross deferred tax assets (liabilities)	(95.7)	(58.9)
Valuation allowance	(27.9)	(83.9)
Deferred tax liabilities, net	(123.6)	(142.8)
Deferred tax assets	37.3	16.4
Non-current liabilities	$ (160.9)	$ (159.2)