Deferred revenue - Deferred revenue rollforward (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Aug. 01, 2015	Aug. 02, 2014	Aug. 01, 2015	Aug. 02, 2014
Sterling Jewelers
Deferred Revenue Warranty [Roll Forward]
ESP deferred revenue, beginning of period	$ 690.7	$ 619.6	$ 668.9	$ 601.2
Plans sold	59.1	53.9	128.4	118.1
Revenue recognized	(58.4)	(46.9)	(105.9)	(92.7)
ESP deferred revenue, end of period	691.4	626.6	691.4	626.6
Zale
Deferred Revenue Arrangement [Line Items]
Product Warranty Accrual, Additions from Business Acquisition	0.0	93.0	0.0	93.0
Deferred Revenue Warranty [Roll Forward]
ESP deferred revenue, beginning of period	129.3	0.0	120.3	0.0
Plans sold	29.4	19.3	64.6	19.3
Revenue recognized	(26.4)	(13.2)	(52.6)	(13.2)
ESP deferred revenue, end of period	$ 132.3	$ 99.1	$ 132.3	$ 99.1