Revenue recognition - ESP Deferred Revenue Rollforward (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Oct. 30, 2021	Oct. 31, 2020	Oct. 30, 2021	Oct. 31, 2020
Change in Contract with Customer, Liability [Roll Forward]
ESP deferred revenue, beginning of period			$ 1,072.0
Plans sold			47.1	$ 25.2
ESP deferred revenue, end of period	$ 1,120.2	$ 1,022.8	1,120.2	1,022.8
Extended Service Plan
Change in Contract with Customer, Liability [Roll Forward]
ESP deferred revenue, beginning of period	1,063.8	990.5	1,028.9	960.0
Plans sold	103.2	83.8	345.9	193.2
Revenue recognized	(100.7)	(91.1)	(308.5)	(170.0)
ESP deferred revenue, end of period	1,066.3	983.2	1,066.3	983.2
Extended Service Plan and Voucher Promotions
Change in Contract with Customer, Liability [Roll Forward]
Revenue recognized	$ (56.4)	$ (61.6)	$ (192.8)	$ (115.8)