Condensed consolidating financial information - Condensed consolidated income statement (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jul. 30, 2016	Aug. 01, 2015	Jul. 30, 2016	Aug. 01, 2015
Condensed Income Statements, Captions [Line Items]
Sales	$ 1,373.4	$ 1,410.6	$ 2,952.3	$ 2,941.2
Cost of sales	(908.5)	(919.8)	(1,887.0)	(1,884.5)
Gross margin	464.9	490.8	1,065.3	1,056.7
Selling, general and administrative expenses	(415.7)	(452.8)	(878.4)	(906.0)
Other operating income, net	70.7	62.8	145.0	126.3
Operating income	119.9	100.8	331.9	277.0
Intra-entity interest income (expense)	0.0	0.0	0.0	0.0
Interest expense, net	(11.9)	(11.1)	(23.7)	(22.1)
Income before income taxes	108.0	89.7	308.2	254.9
Income taxes	(26.1)	(27.5)	(79.5)	(73.9)
Equity in income of subsidiaries	0.0	0.0	0.0	0.0
Net income	81.9	62.2	228.7	181.0
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	(130.3)	(114.8)	(446.7)	(387.1)
Net income	(130.3)	(114.8)	(446.7)	(387.1)
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	(0.5)	(0.9)	(0.6)	(1.2)
Other operating income, net	0.0	0.0	0.0	0.0
Operating income	(0.5)	(0.9)	(0.6)	(1.2)
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	(0.5)	(0.9)	(0.6)	(1.2)
Income taxes	0.0	0.0	0.0	0.0
Equity in income of subsidiaries	82.4	63.1	229.3	182.2
Net income	81.9	62.2	228.7	181.0
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	4.7	9.4	9.4
Interest expense, net	(4.9)	(4.9)	(9.8)	(9.8)
Income before income taxes	(0.2)	(0.2)	(0.4)	(0.4)
Income taxes	0.1	0.1	0.1	0.1
Equity in income of subsidiaries	0.0	0.0	0.0	0.0
Net income	(0.1)	(0.1)	(0.3)	(0.3)
Guarantor Subsidiaries | Reportable Legal Entities
Condensed Income Statements, Captions [Line Items]
Sales	1,314.9	1,391.3	2,833.2	2,902.3
Cost of sales	(897.2)	(914.2)	(1,866.3)	(1,875.2)
Gross margin	417.7	477.1	966.9	1,027.1
Selling, general and administrative expenses	(390.3)	(444.9)	(828.9)	(889.1)
Other operating income, net	80.4	60.7	152.0	124.2
Operating income	107.8	92.9	290.0	262.2
Intra-entity interest income (expense)	(47.5)	(47.0)	(94.4)	(93.1)
Interest expense, net	(3.9)	(3.4)	(7.6)	(6.9)
Income before income taxes	56.4	42.5	188.0	162.2
Income taxes	(22.4)	(26.2)	(76.6)	(74.7)
Equity in income of subsidiaries	15.5	24.7	100.7	100.7
Net income	49.5	41.0	212.1	188.2
Non-Guarantor Subsidiaries | Reportable Legal Entities
Condensed Income Statements, Captions [Line Items]
Sales	58.5	19.3	119.1	38.9
Cost of sales	(11.3)	(5.6)	(20.7)	(9.3)
Gross margin	47.2	13.7	98.4	29.6
Selling, general and administrative expenses	(24.9)	(7.0)	(48.9)	(15.7)
Other operating income, net	(9.7)	2.1	(7.0)	2.1
Operating income	12.6	8.8	42.5	16.0
Intra-entity interest income (expense)	42.8	42.3	85.0	83.7
Interest expense, net	(3.1)	(2.8)	(6.3)	(5.4)
Income before income taxes	52.3	48.3	121.2	94.3
Income taxes	(3.8)	(1.4)	(3.0)	0.7
Equity in income of subsidiaries	32.4	27.0	116.7	104.2
Net income	$ 80.9	$ 73.9	$ 234.9	$ 199.2