Segment information - Summary of Activity by Segment (Details) - USD ($) $ in Millions	3 Months Ended					9 Months Ended		12 Months Ended
	Nov. 02, 2019	Aug. 03, 2019	Feb. 02, 2019	Nov. 03, 2018	May 05, 2018	Nov. 02, 2019	Nov. 03, 2018	Feb. 02, 2019
Segment Reporting Information [Line Items]
Sales	$ 1,187.7			$ 1,191.7		$ 3,983.8	$ 4,092.4
Operating income (loss)	(39.9)			(48.8)		(64.9)	(681.1)
Impairment		$ 47.7				47.7		$ 521.2
Inventory write-down	1.4			0.0		5.8	63.2
Restructuring charges	9.2			9.5		59.4	35.6
Credit transaction, net						0.0	160.4
Goodwill and intangible impairments	0.0		$ 286.7	0.0		47.7	448.7
Total assets	6,101.6		4,420.1	4,907.5		6,101.6	4,907.5	4,420.1
North America
Segment Reporting Information [Line Items]
Sales	1,070.7			1,064.3		3,612.0	3,698.8
Operating income (loss)	(5.2)			(19.5)		67.1	(561.0)
Impairment			208.8		$ 308.8	47.7		517.6
Inventory write-down	1.4					2.6
Restructuring charges							53.7
Credit transaction, net							160.4
Goodwill and intangible impairments					$ 448.7
Total assets	5,313.5		3,943.0	4,428.6		5,313.5	4,428.6	3,943.0
International
Segment Reporting Information [Line Items]
Sales	106.4			121.3		331.8	381.5
Operating income (loss)	(5.1)			(4.4)		(14.1)	(18.1)
Inventory write-down							3.8
Total assets	577.0		367.4	387.1		577.0	387.1	367.4
Other
Segment Reporting Information [Line Items]
Sales	10.6			6.1		40.0	12.1
Operating income (loss)	(29.6)			(24.9)		(117.9)	(102.0)
Impairment			3.6			0.0		3.6
Restructuring charges	9.2			9.5		62.6	41.3
Transaction-related costs				0.4			7.0
Total assets	$ 211.1		$ 109.7	$ 91.8		$ 211.1	$ 91.8	$ 109.7