Accumulated other comprehensive income (loss) - Reclassifications out of AOCI (Details) - USD ($) $ in Millions	3 Months Ended						9 Months Ended
	Oct. 31, 2020	Aug. 01, 2020	May 02, 2020	Nov. 02, 2019	Aug. 03, 2019	May 04, 2019	Oct. 31, 2020	Nov. 02, 2019
Accumulated Other Comprehensive Income (Loss) [Line Items]
Cost of sales	$ 863.8			$ 818.6			$ 2,176.0	$ 2,652.2
Interest expense, net	9.1			8.6			25.6	27.9
Other operating income (loss)	(0.4)			0.0			4.3	1.4
Other non-operating income, net	0.0			7.0			0.3	7.5
Income before income taxes	30.6			(41.5)			(374.9)	(85.3)
Income taxes	(21.3)			6.0			105.4	3.7
Net income (loss)	9.3	$ (81.7)	$ (197.1)	(35.5)	$ (36.1)	$ (10.0)	(269.5)	(81.6)
Reclassification out of Accumulated Other Comprehensive Income
Accumulated Other Comprehensive Income (Loss) [Line Items]
Net income (loss)	(1.5)			0.9			(10.0)	1.0
Losses (gains) on cash flow hedges | Reclassification out of Accumulated Other Comprehensive Income
Accumulated Other Comprehensive Income (Loss) [Line Items]
Net income (loss)	(1.9)			(0.4)			(10.8)	(0.8)
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	(1.8)			(0.5)			(3.5)	(1.0)
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	0.0			(0.3)			0.0	(0.9)
Losses (gains) on cash flow hedges, excluding dedesignated | Reclassification out of Accumulated Other Comprehensive Income | Interest rate swaps
Accumulated Other Comprehensive Income (Loss) [Line Items]
Interest expense, net	0.0			0.0			0.0	(0.6)
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	(1.8)			(0.2)			(3.5)	0.5
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			(9.9)	0.0
Income taxes	(0.1)			0.1			2.6	0.2
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 (loss)	0.0			0.0			(0.6)	0.0
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 (loss)	0.0			0.0			(9.3)	0.0
Defined benefit pension plan items | Reclassification out of Accumulated Other Comprehensive Income
Accumulated Other Comprehensive Income (Loss) [Line Items]
Income before income taxes	0.5			0.3			0.9	0.9
Income taxes	(0.1)			0.0			(0.1)	(0.1)
Net income (loss)	0.4			0.3			0.8	0.8
Actuarial gains (losses) | Reclassification out of Accumulated Other Comprehensive Income
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other non-operating income, net	0.1			0.2			0.2	0.8
Prior service credits (costs) | Reclassification out of Accumulated Other Comprehensive Income
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other non-operating income, net	0.4			0.1			0.7	0.1
Gains (losses) on available-for-sale securities, net | Reclassification out of Accumulated Other Comprehensive Income
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other operating income (loss)	0.0			1.0			0.0	1.0
Income taxes	0.0			0.0			0.0	0.0
Net income (loss)	$ 0.0			$ 1.0			$ 0.0	$ 1.0