Goodwill and intangibles - Composition of Intangible Assets and Liabilities (Details) - USD ($) $ in Millions	Feb. 01, 2020	Feb. 02, 2019
Intangible assets, net:
Definite-lived intangible assets, gross carrying amount	$ 53.2	$ 53.3
Definite-lived intangible assets, accumulated amortization	(50.9)	(50.1)
Net carrying amount	2.3	3.2
Indefinite-lived intangible assets	475.4	475.9
Indefinite-lived intangible assets, accumulated impairment loss	(213.9)	(214.1)
Indefinite-lived intangible assets, net	261.5	261.8
Intangible assets, gross	528.6	529.2
Total intangible assets, net	263.8	265.0
Definite-lived intangible liabilities:
Gross carrying amount	(113.9)	(113.9)
Accumulated amortization	98.0	92.5
Total	$ (15.9)	$ (21.4)