Condensed consolidating financial information - Condensed consolidated income statement (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Aug. 01, 2015	Aug. 02, 2014	Aug. 01, 2015	Aug. 02, 2014
Condensed Income Statements, Captions [Line Items]
Sales	$ 1,410.6	$ 1,225.9	$ 2,941.2	$ 2,282.0
Cost of sales	(919.8)	(816.9)	(1,884.5)	(1,465.8)
Gross margin	490.8	409.0	1,056.7	816.2
Selling, general and administrative expenses	(452.8)	(379.2)	(906.0)	(689.7)
Other operating income, net	62.8	53.7	126.3	107.7
Operating income	100.8	83.5	277.0	234.2
Intra-entity interest income (expense)	0.0	0.0	0.0	0.0
Interest expense, net	(11.1)	(13.7)	(22.1)	(15.5)
Income before income taxes	89.7	69.8	254.9	218.7
Income taxes	(27.5)	(11.8)	(73.9)	(64.1)
Equity in income of subsidiaries	0.0	0.0	0.0	0.0
Net income	62.2	58.0	181.0	154.6
Consolidation, Eliminations
Condensed Income Statements, Captions [Line Items]
Sales	0.0	0.0	0.0	0.0
Cost of sales	0.0	0.0	0.0	0.0
Gross margin	0.0	0.0	0.0	0.0
Selling, general and administrative expenses	0.0	0.0	0.0	0.0
Other operating income, net	0.0	0.0	0.0	0.0
Operating income	0.0	0.0	0.0	0.0
Intra-entity interest income (expense)	0.0	0.0	0.0	0.0
Interest expense, net	0.0	0.0	0.0	0.0
Income before income taxes	0.0	0.0	0.0	0.0
Income taxes	0.0	0.0	0.0	0.0
Equity in income of subsidiaries	(114.8)	(116.1)	(387.1)	(385.1)
Net income	(114.8)	(116.1)	(387.1)	(385.1)
Signet Jewelers Limited | Reportable Legal Entities
Condensed Income Statements, Captions [Line Items]
Sales	0.0	0.0	0.0	0.0
Cost of sales	0.0	0.0	0.0	0.0
Gross margin	0.0	0.0	0.0	0.0
Selling, general and administrative expenses	(0.9)	(0.4)	(1.2)	(0.8)
Other operating income, net	0.0	0.0	0.0	0.0
Operating income	(0.9)	(0.4)	(1.2)	(0.8)
Intra-entity interest income (expense)	0.0	0.0	0.0	0.0
Interest expense, net	0.0	0.0	0.0	0.0
Income before income taxes	(0.9)	(0.4)	(1.2)	(0.8)
Income taxes	0.0	0.0	0.0	0.0
Equity in income of subsidiaries	63.1	58.4	182.2	155.4
Net income	62.2	58.0	181.0	154.6
Signet UK Finance plc | Reportable Legal Entities
Condensed Income Statements, Captions [Line Items]
Sales	0.0	0.0	0.0	0.0
Cost of sales	0.0	0.0	0.0	0.0
Gross margin	0.0	0.0	0.0	0.0
Selling, general and administrative expenses	0.0	0.0	0.0	0.0
Other operating income, net	0.0	0.0	0.0	0.0
Operating income	0.0	0.0	0.0	0.0
Intra-entity interest income (expense)	4.7	3.8	9.4	3.8
Interest expense, net	(4.9)	(3.9)	(9.8)	(3.9)
Income before income taxes	(0.2)	(0.1)	(0.4)	(0.1)
Income taxes	0.1	0.0	0.1	0.0
Equity in income of subsidiaries	0.0	0.0	0.0	0.0
Net income	(0.1)	(0.1)	(0.3)	(0.1)
Guarantor Subsidiaries | Reportable Legal Entities
Condensed Income Statements, Captions [Line Items]
Sales	1,391.3	1,207.5	2,902.3	2,251.2
Cost of sales	(914.2)	(811.4)	(1,875.2)	(1,459.0)
Gross margin	477.1	396.1	1,027.1	792.2
Selling, general and administrative expenses	(444.9)	(371.9)	(889.1)	(675.7)
Other operating income, net	60.7	54.0	124.2	106.0
Operating income	92.9	78.2	262.2	222.5
Intra-entity interest income (expense)	(47.0)	(34.8)	(93.1)	(41.8)
Interest expense, net	(3.4)	(7.8)	(6.9)	(9.6)
Income before income taxes	42.5	35.6	162.2	171.1
Income taxes	(26.2)	(13.3)	(74.7)	(69.2)
Equity in income of subsidiaries	24.7	31.9	100.7	123.1
Net income	41.0	54.2	188.2	225.0
Non-Guarantor Subsidiaries | Reportable Legal Entities
Condensed Income Statements, Captions [Line Items]
Sales	19.3	18.4	38.9	30.8
Cost of sales	(5.6)	(5.5)	(9.3)	(6.8)
Gross margin	13.7	12.9	29.6	24.0
Selling, general and administrative expenses	(7.0)	(6.9)	(15.7)	(13.2)
Other operating income, net	2.1	(0.3)	2.1	1.7
Operating income	8.8	5.7	16.0	12.5
Intra-entity interest income (expense)	42.3	31.0	83.7	38.0
Interest expense, net	(2.8)	(2.0)	(5.4)	(2.0)
Income before income taxes	48.3	34.7	94.3	48.5
Income taxes	(1.4)	1.5	0.7	5.1
Equity in income of subsidiaries	27.0	25.8	104.2	106.6
Net income	$ 73.9	$ 62.0	$ 199.2	$ 160.2