Shareholders' equity - Narrative (Details) - USD ($)	3 Months Ended				6 Months Ended		66 Months Ended
	Jul. 29, 2023	Apr. 29, 2023	Jul. 30, 2022	Apr. 30, 2022	Jul. 29, 2023	Jul. 30, 2022	Jul. 29, 2023	Mar. 31, 2023	Jan. 28, 2023
Class of Stock [Line Items]
Amount of preferred dividends in arrears	$ 0		$ 0		$ 0	$ 0
Amount repurchased	43,300,000	$ 39,100,000	$ 22,800,000	$ 268,200,000
2017 Program
Class of Stock [Line Items]
Stock repurchase program, authorized amount									$ 1,700,000,000
Remaining authorized repurchase amount	$ 717,900,000				717,900,000		$ 717,900,000	$ 775,000,000	$ 537,300,000
Amount repurchased					$ 82,400,000	$ 341,000,000.0	$ 1,200,000,000