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Restructuring Plans - Schedule of Plan Liabilities (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended		33 Months Ended
	Oct. 31, 2020	Nov. 02, 2019	Oct. 31, 2020	Nov. 02, 2019	Oct. 31, 2020
Restructuring Reserve [Roll Forward]
Charged to expense	$ 3.6	$ 9.2	$ 45.2	$ 59.4
Signet Path to Brillance
Restructuring Reserve [Roll Forward]
Beginning balance			12.4
Payments and other adjustments			(43.8)
Charged to expense	5.6	$ 10.6	46.6	$ 65.2	$ 251.6
Ending balance	15.2		15.2		15.2
Termination benefits \| Signet Path to Brillance
Restructuring Reserve [Roll Forward]
Beginning balance			2.0
Payments and other adjustments			(19.2)
Charged to expense	2.3		25.4		51.2
Ending balance	8.2		8.2		8.2
Store closure and other costs \| Signet Path to Brillance
Restructuring Reserve [Roll Forward]
Beginning balance			10.4
Payments and other adjustments			(24.6)
Charged to expense			21.2
Ending balance	$ 7.0		$ 7.0		$ 7.0