Goodwill and intangibles - Composition of Finite-Lived Intangibles (Details) - USD ($) $ in Millions	Nov. 02, 2019	Feb. 02, 2019	Nov. 03, 2018
Intangible assets, net:
Gross carrying amount	$ 53.2	$ 53.3	$ 53.3
Accumulated amortization	(50.7)	(50.1)	(49.3)
Net carrying amount	2.5	3.2	4.0
Indefinite-lived intangible assets, gross	475.8	475.9	475.9
Accumulated amortization	(214.1)	(214.1)	(139.7)
Indefinite-lived intangible assets	261.7	261.8	336.2
Intangible assets, gross	529.0	529.2	529.2
Accumulated amortization, net	(264.8)	(264.2)	(189.0)
Total intangible assets, net	264.2	265.0	340.2
Intangible liabilities, net
Gross carrying amount	(113.9)	(113.9)	(113.9)
Accumulated amortization	96.7	92.5	90.7
Total	$ (17.2)	$ (21.4)	$ (23.2)