Restructuring Plans - Restructuring and Related Costs (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended		30 Months Ended
	Aug. 01, 2020	Aug. 03, 2019	Aug. 01, 2020	Aug. 03, 2019	Aug. 01, 2020
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 28.9	$ 23.4	$ 41.6	$ 50.2
Cost of sales
Restructuring Cost and Reserve [Line Items]
Inventory charges	(0.2)	4.4	(0.6)	4.4
Restructuring Charges
Restructuring Cost and Reserve [Line Items]
Restructuring charges	28.9	23.4	41.6	50.2
Signet Path to Brillance
Restructuring Cost and Reserve [Line Items]
Restructuring charges	28.7	$ 27.8	41.0	$ 54.6	$ 246.0
Inventory charges | Signet Path to Brillance
Restructuring Cost and Reserve [Line Items]
Restructuring charges	(0.2)		(0.6)		70.8
Termination benefits | Signet Path to Brillance
Restructuring Cost and Reserve [Line Items]
Restructuring charges	20.2		23.1		48.9
Store closure and other costs | Signet Path to Brillance
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 8.7		$ 18.5		$ 126.3