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Restructuring Plans - Restructuring and Related Costs (Details) - USD ($) $ in Millions	12 Months Ended
	Feb. 02, 2019	Feb. 03, 2018	Jan. 28, 2017
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 84.9	$ 0.0	$ 0.0
Non-cash charges	22.7
Signet Path to Brillance
Restructuring Cost and Reserve [Line Items]
Restructuring charges	125.9
Signet Path to Brillance \| Cost of sales
Restructuring Cost and Reserve [Line Items]
Inventory charges	62.2
Signet Path to Brillance \| Restructuring charges
Restructuring Cost and Reserve [Line Items]
Other Plan related expenses	$ 63.7