Retirement plans - Fair Value Measurements of Plan Assets (Details) - Foreign Plan - Pension plan - USD ($) $ in Millions	Jan. 30, 2021	Feb. 01, 2020	Feb. 02, 2019
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 299.2	$ 281.9	$ 245.5
Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	209.5	193.8
Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	69.2	63.9
Diversified equity securities | Fair Value, Inputs, Level 1, 2 and 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	13.0	15.1
Diversified equity securities | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Diversified equity securities | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	13.0	15.1
Diversified growth funds | Fair Value, Inputs, Level 1, 2 and 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	44.4	49.8
Diversified growth funds | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	44.4	49.8
Diversified growth funds | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Diversified growth funds | NAV
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	18.0	17.8
Fixed income – government bonds | Fair Value, Inputs, Level 1, 2 and 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	161.4	139.7
Fixed income – government bonds | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	161.4	139.7
Fixed income – government bonds | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Corporate bonds and notes | Fair Value, Inputs, Level 1, 2 and 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	56.2	48.8
Corporate bonds and notes | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Corporate bonds and notes | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	56.2	48.8
Cash | Fair Value, Inputs, Level 1, 2 and 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	3.7	4.3
Cash | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	3.7	4.3
Cash | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Property | NAV
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 2.5	$ 6.4