Revenue recognition - Disaggregation of Revenue (Details) - USD ($) $ in Millions	12 Months Ended
	Feb. 02, 2019	Feb. 03, 2018	Jan. 28, 2017
Disaggregation of Revenue [Line Items]
Total sales	$ 6,247.1	$ 6,253.0	$ 6,408.4
Store
Disaggregation of Revenue [Line Items]
Total sales	5,535.8	5,734.2	6,027.2
eCommerce
Disaggregation of Revenue [Line Items]
Total sales	682.4	497.7	363.1
Other
Disaggregation of Revenue [Line Items]
Total sales	28.9	21.1	18.1
North America
Disaggregation of Revenue [Line Items]
Total sales	5,641.7	5,615.2	5,743.2
North America | Store
Disaggregation of Revenue [Line Items]
Total sales	5,022.4	5,176.7	5,432.0
North America | eCommerce
Disaggregation of Revenue [Line Items]
Total sales	619.3	438.5	311.2
North America | Other
Disaggregation of Revenue [Line Items]
Total sales	0.0	0.0	0.0
International
Disaggregation of Revenue [Line Items]
Total sales	576.5	616.7	647.1
International | Store
Disaggregation of Revenue [Line Items]
Total sales	513.4	557.5	595.2
International | eCommerce
Disaggregation of Revenue [Line Items]
Total sales	63.1	59.2	51.9
International | Other
Disaggregation of Revenue [Line Items]
Total sales	0.0	0.0	0.0
Other
Disaggregation of Revenue [Line Items]
Total sales	28.9	21.1	18.1
Other | Store
Disaggregation of Revenue [Line Items]
Total sales	0.0	0.0	0.0
Other | eCommerce
Disaggregation of Revenue [Line Items]
Total sales	0.0	0.0	0.0
Other | Other
Disaggregation of Revenue [Line Items]
Total sales	28.9	21.1	18.1
Bridal
Disaggregation of Revenue [Line Items]
Total sales	2,712.6	2,654.6	2,695.6
Bridal | North America
Disaggregation of Revenue [Line Items]
Total sales	2,478.6	2,407.3	2,429.0
Bridal | International
Disaggregation of Revenue [Line Items]
Total sales	234.0	247.3	266.6
Bridal | Other
Disaggregation of Revenue [Line Items]
Total sales	0.0	0.0	0.0
Fashion
Disaggregation of Revenue [Line Items]
Total sales	2,254.4	2,305.2	2,341.7
Fashion | North America
Disaggregation of Revenue [Line Items]
Total sales	2,128.1	2,168.2	2,190.8
Fashion | International
Disaggregation of Revenue [Line Items]
Total sales	126.3	137.0	150.9
Fashion | Other
Disaggregation of Revenue [Line Items]
Total sales	0.0	0.0	0.0
Watches
Disaggregation of Revenue [Line Items]
Total sales	429.1	439.1	462.6
Watches | North America
Disaggregation of Revenue [Line Items]
Total sales	238.2	243.6	263.0
Watches | International
Disaggregation of Revenue [Line Items]
Total sales	190.9	195.5	199.6
Watches | Other
Disaggregation of Revenue [Line Items]
Total sales	0.0	0.0	0.0
Other
Disaggregation of Revenue [Line Items]
Total sales	851.0	854.1	908.5
Other | North America
Disaggregation of Revenue [Line Items]
Total sales	796.8	796.1	860.4
Other | International
Disaggregation of Revenue [Line Items]
Total sales	25.3	36.9	30.0
Other | Other
Disaggregation of Revenue [Line Items]
Total sales	28.9	21.1	$ 18.1
James Allen | North America | eCommerce
Disaggregation of Revenue [Line Items]
Total sales	$ 223.7	$ 88.1