Revenue recognition - Disaggregation of Revenue (Details) - USD ($) $ in Millions	12 Months Ended
	Jan. 30, 2021	Feb. 01, 2020	Feb. 02, 2019
Disaggregation of Revenue [Line Items]
Total sales	$ 5,226.9	$ 6,137.1	$ 6,247.1
Bridal
Disaggregation of Revenue [Line Items]
Total sales	2,306.9	2,617.7	2,712.6
Fashion
Disaggregation of Revenue [Line Items]
Total sales	2,057.1	2,241.5	2,254.4
Watches
Disaggregation of Revenue [Line Items]
Total sales	254.1	384.0	429.1
Other
Disaggregation of Revenue [Line Items]
Total sales	608.8	893.9	851.0
Store
Disaggregation of Revenue [Line Items]
Total sales	4,011.8	5,333.4	5,535.8
Kay
Disaggregation of Revenue [Line Items]
Total sales	2,008.6	2,414.0	2,475.2
Zales
Disaggregation of Revenue [Line Items]
Total sales	1,121.6	1,276.8	1,280.5
Jared
Disaggregation of Revenue [Line Items]
Total sales	920.9	1,088.1	1,141.4
Piercing Pagoda
Disaggregation of Revenue [Line Items]
Total sales	337.5	331.7	302.5
James Allen
Disaggregation of Revenue [Line Items]
Total sales	301.4	250.6	223.7
Peoples
Disaggregation of Revenue [Line Items]
Total sales	150.9	204.6	218.4
International
Disaggregation of Revenue [Line Items]
Total sales	355.9	518.0	576.5
Other
Disaggregation of Revenue [Line Items]
Total sales	30.1	53.3	28.9
eCommerce
Disaggregation of Revenue [Line Items]
Total sales	1,185.0	750.4	682.4
Other
Disaggregation of Revenue [Line Items]
Total sales	30.1	53.3	28.9
North America
Disaggregation of Revenue [Line Items]
Total sales	4,840.9	5,565.8	5,641.7
North America | Bridal
Disaggregation of Revenue [Line Items]
Total sales	2,140.5	2,403.4	2,478.6
North America | Fashion
Disaggregation of Revenue [Line Items]
Total sales	1,987.9	2,131.0	2,128.1
North America | Watches
Disaggregation of Revenue [Line Items]
Total sales	145.6	214.9	238.2
North America | Other
Disaggregation of Revenue [Line Items]
Total sales	566.9	816.5	796.8
North America | Store
Disaggregation of Revenue [Line Items]
Total sales	3,772.9	4,880.2	5,022.4
North America | Kay
Disaggregation of Revenue [Line Items]
Total sales	2,008.6	2,414.0	2,475.2
North America | Zales
Disaggregation of Revenue [Line Items]
Total sales	1,121.6	1,276.8	1,280.5
North America | Jared
Disaggregation of Revenue [Line Items]
Total sales	920.9	1,088.1	1,141.4
North America | Piercing Pagoda
Disaggregation of Revenue [Line Items]
Total sales	337.5	331.7	302.5
North America | James Allen
Disaggregation of Revenue [Line Items]
Total sales	301.4	250.6	223.7
North America | Peoples
Disaggregation of Revenue [Line Items]
Total sales	150.9	204.6	218.4
North America | International
Disaggregation of Revenue [Line Items]
Total sales	0.0	0.0	0.0
North America | Other
Disaggregation of Revenue [Line Items]
Total sales	0.0	0.0	0.0
North America | eCommerce
Disaggregation of Revenue [Line Items]
Total sales	1,068.0	685.6	619.3
North America | Other
Disaggregation of Revenue [Line Items]
Total sales	0.0	0.0	0.0
International
Disaggregation of Revenue [Line Items]
Total sales	355.9	518.0	576.5
International | Bridal
Disaggregation of Revenue [Line Items]
Total sales	166.4	214.3	234.0
International | Fashion
Disaggregation of Revenue [Line Items]
Total sales	69.2	110.5	126.3
International | Watches
Disaggregation of Revenue [Line Items]
Total sales	108.5	169.1	190.9
International | Other
Disaggregation of Revenue [Line Items]
Total sales	11.8	24.1	25.3
International | Store
Disaggregation of Revenue [Line Items]
Total sales	238.9	453.2	513.4
International | Kay
Disaggregation of Revenue [Line Items]
Total sales	0.0	0.0	0.0
International | Zales
Disaggregation of Revenue [Line Items]
Total sales	0.0	0.0	0.0
International | Jared
Disaggregation of Revenue [Line Items]
Total sales	0.0	0.0	0.0
International | Piercing Pagoda
Disaggregation of Revenue [Line Items]
Total sales	0.0	0.0	0.0
International | James Allen
Disaggregation of Revenue [Line Items]
Total sales	0.0	0.0	0.0
International | Peoples
Disaggregation of Revenue [Line Items]
Total sales	0.0	0.0	0.0
International | International
Disaggregation of Revenue [Line Items]
Total sales	355.9	518.0	576.5
International | Other
Disaggregation of Revenue [Line Items]
Total sales	0.0	0.0	0.0
International | eCommerce
Disaggregation of Revenue [Line Items]
Total sales	117.0	64.8	63.1
International | Other
Disaggregation of Revenue [Line Items]
Total sales	0.0	0.0	0.0
Other
Disaggregation of Revenue [Line Items]
Total sales	30.1	53.3	28.9
Other | Bridal
Disaggregation of Revenue [Line Items]
Total sales	0.0	0.0	0.0
Other | Fashion
Disaggregation of Revenue [Line Items]
Total sales	0.0	0.0	0.0
Other | Watches
Disaggregation of Revenue [Line Items]
Total sales	0.0	0.0	0.0
Other | Other
Disaggregation of Revenue [Line Items]
Total sales	30.1	53.3	28.9
Other | Store
Disaggregation of Revenue [Line Items]
Total sales	0.0	0.0	0.0
Other | Kay
Disaggregation of Revenue [Line Items]
Total sales	0.0	0.0	0.0
Other | Zales
Disaggregation of Revenue [Line Items]
Total sales	0.0	0.0	0.0
Other | Jared
Disaggregation of Revenue [Line Items]
Total sales	0.0	0.0	0.0
Other | Piercing Pagoda
Disaggregation of Revenue [Line Items]
Total sales	0.0	0.0	0.0
Other | James Allen
Disaggregation of Revenue [Line Items]
Total sales	0.0	0.0	0.0
Other | Peoples
Disaggregation of Revenue [Line Items]
Total sales	0.0	0.0	0.0
Other | International
Disaggregation of Revenue [Line Items]
Total sales	0.0	0.0	0.0
Other | Other
Disaggregation of Revenue [Line Items]
Total sales	30.1	53.3	28.9
Other | eCommerce
Disaggregation of Revenue [Line Items]
Total sales	0.0	0.0	0.0
Other | Other
Disaggregation of Revenue [Line Items]
Total sales	$ 30.1	$ 53.3	$ 28.9