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Restructuring Plans - Restructuring and Related Costs (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended		21 Months Ended
	Nov. 02, 2019	Nov. 03, 2018	Nov. 02, 2019	Nov. 03, 2018	Nov. 02, 2019
Restructuring Cost and Reserve [Line Items]
Inventory charges	$ 1.4	$ 0.0	$ 5.8	$ 63.2
Restructuring charges	9.2	9.5	59.4	35.6
Signet Path to Brillance
Restructuring Cost and Reserve [Line Items]
Restructuring charges	10.6	9.5	65.2	98.8	$ 191.1
Signet Path to Brillance \| Cost of sales
Restructuring Cost and Reserve [Line Items]
Inventory charges	1.4	0.0	5.8	63.2
Signet Path to Brillance \| Restructuring Charges
Restructuring Cost and Reserve [Line Items]
Other Plan related expenses	9.2	$ 9.5	59.4	$ 35.6
Inventory charges \| Signet Path to Brillance
Restructuring Cost and Reserve [Line Items]
Restructuring charges	1.4		5.8		68.0
Termination benefits \| Signet Path to Brillance
Restructuring Cost and Reserve [Line Items]
Restructuring charges	1.0		15.8		25.5
Store closure and other costs \| Signet Path to Brillance
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 8.2		$ 43.6		$ 97.6