Accumulated other comprehensive income (loss) - Reclassifications out of AOCI (Details) - USD ($) $ in Millions	3 Months Ended				6 Months Ended
	Jul. 31, 2021	May 01, 2021	Aug. 01, 2020	May 02, 2020	Jul. 31, 2021	Aug. 01, 2020
Accumulated Other Comprehensive Income (Loss) [Line Items]
Cost of sales	$ 1,070.5		$ 663.9		$ 2,080.9	$ 1,312.2
Other operating income, net	9.3		1.1		12.4	4.7
Other non-operating income, net	0.1		0.2		0.2	0.3
Income before income taxes	221.1		(98.9)		386.0	(405.5)
Income taxes	3.5		17.2		(23.0)	126.7
Net income (loss)	224.6	$ 138.4	(81.7)	$ (197.1)	363.0	(278.8)
Reclassification out of Accumulated Other Comprehensive Income
Accumulated Other Comprehensive Income (Loss) [Line Items]
Net income (loss)	0.4		(0.7)		0.8	(8.5)
Losses (gains) on cash flow hedges | Reclassification out of Accumulated Other Comprehensive Income
Accumulated Other Comprehensive Income (Loss) [Line Items]
Net income (loss)	0.2		(0.8)		0.4	(8.9)
Losses (gains) on cash flow hedges, excluding dedesignated | Reclassification out of Accumulated Other Comprehensive Income
Accumulated Other Comprehensive Income (Loss) [Line Items]
Income before income taxes	0.3		(0.9)		0.5	(1.7)
Losses (gains) on cash flow hedges, excluding dedesignated | Reclassification out of Accumulated Other Comprehensive Income | Foreign currency contracts
Accumulated Other Comprehensive Income (Loss) [Line Items]
Cost of sales	0.2		0.0		0.3	0.0
Losses (gains) on cash flow hedges, excluding dedesignated | Reclassification out of Accumulated Other Comprehensive Income | Commodity contracts
Accumulated Other Comprehensive Income (Loss) [Line Items]
Cost of sales	0.1		(0.9)		0.2	(1.7)
Losses (gains) on dedesignating cash flow hedges | Reclassification out of Accumulated Other Comprehensive Income
Accumulated Other Comprehensive Income (Loss) [Line Items]
Income before income taxes	0.0		0.0		0.0	(9.9)
Income taxes	(0.1)		0.1		(0.1)	2.7
Losses (gains) on dedesignating cash flow hedges | Reclassification out of Accumulated Other Comprehensive Income | Foreign currency contracts
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other operating income, net	0.0		0.0		0.0	(0.6)
Losses (gains) on dedesignating cash flow hedges | Reclassification out of Accumulated Other Comprehensive Income | Commodity contracts
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other operating income, net	0.0		0.0		0.0	(9.3)
Defined benefit pension plan items | Reclassification out of Accumulated Other Comprehensive Income
Accumulated Other Comprehensive Income (Loss) [Line Items]
Income before income taxes	0.3		0.1		0.5	0.4
Income taxes	(0.1)		0.0		(0.1)	0.0
Net income (loss)	0.2		0.1		0.4	0.4
Actuarial gains (losses) | Reclassification out of Accumulated Other Comprehensive Income
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other non-operating income, net	0.2		0.0		0.4	0.1
Prior service credits (costs) | Reclassification out of Accumulated Other Comprehensive Income
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other non-operating income, net	$ 0.1		$ 0.1		$ 0.1	$ 0.3