Condensed consolidating financial information - Condensed consolidated income statement (Details) - USD ($) $ in Millions	3 Months Ended
	Apr. 30, 2016	May. 02, 2015
Condensed Income Statements, Captions [Line Items]
Sales	$ 1,578.9	$ 1,530.6
Cost of sales	(978.5)	(964.7)
Gross margin	600.4	565.9
Selling, general and administrative expenses	(462.7)	(453.2)
Other operating income, net	74.3	63.5
Operating income	212.0	176.2
Intra-entity interest income (expense)	0.0	0.0
Interest expense, net	(11.8)	(11.0)
Income before income taxes	200.2	165.2
Income taxes	(53.4)	(46.4)
Equity in income of subsidiaries	0.0	0.0
Net income (loss)	146.8	118.8
Consolidation, Eliminations
Condensed Income Statements, Captions [Line Items]
Sales	0.0	0.0
Cost of sales	0.0	0.0
Gross margin	0.0	0.0
Selling, general and administrative expenses	0.0	0.0
Other operating income, net	0.0	0.0
Operating income	0.0	0.0
Intra-entity interest income (expense)	0.0	0.0
Interest expense, net	0.0	0.0
Income before income taxes	0.0	0.0
Income taxes	0.0	0.0
Equity in income of subsidiaries	(316.4)	(272.3)
Net income (loss)	(316.4)	(272.3)
Signet Jewelers Limited | Reportable Legal Entities
Condensed Income Statements, Captions [Line Items]
Sales	0.0	0.0
Cost of sales	0.0	0.0
Gross margin	0.0	0.0
Selling, general and administrative expenses	(0.1)	(0.3)
Other operating income, net	0.0	0.0
Operating income	(0.1)	(0.3)
Intra-entity interest income (expense)	0.0	0.0
Interest expense, net	0.0	0.0
Income before income taxes	(0.1)	(0.3)
Income taxes	0.0	0.0
Equity in income of subsidiaries	146.9	119.1
Net income (loss)	146.8	118.8
Signet UK Finance plc | Reportable Legal Entities
Condensed Income Statements, Captions [Line Items]
Sales	0.0	0.0
Cost of sales	0.0	0.0
Gross margin	0.0	0.0
Selling, general and administrative expenses	0.0	0.0
Other operating income, net	0.0	0.0
Operating income	0.0	0.0
Intra-entity interest income (expense)	4.7	4.7
Interest expense, net	(4.9)	(4.9)
Income before income taxes	(0.2)	(0.2)
Income taxes	0.0	0.0
Equity in income of subsidiaries	0.0	0.0
Net income (loss)	(0.2)	(0.2)
Guarantor Subsidiaries | Reportable Legal Entities
Condensed Income Statements, Captions [Line Items]
Sales	1,518.3	1,511.0
Cost of sales	(969.1)	(961.0)
Gross margin	549.2	550.0
Selling, general and administrative expenses	(438.6)	(444.2)
Other operating income, net	71.6	63.5
Operating income	182.2	169.3
Intra-entity interest income (expense)	(46.9)	(46.1)
Interest expense, net	(3.7)	(3.5)
Income before income taxes	131.6	119.7
Income taxes	(54.2)	(48.5)
Equity in income of subsidiaries	85.2	76.0
Net income (loss)	162.6	147.2
Non-Guarantor Subsidiaries | Reportable Legal Entities
Condensed Income Statements, Captions [Line Items]
Sales	60.6	19.6
Cost of sales	(9.4)	(3.7)
Gross margin	51.2	15.9
Selling, general and administrative expenses	(24.0)	(8.7)
Other operating income, net	2.7	0.0
Operating income	29.9	7.2
Intra-entity interest income (expense)	42.2	41.4
Interest expense, net	(3.2)	(2.6)
Income before income taxes	68.9	46.0
Income taxes	0.8	2.1
Equity in income of subsidiaries	84.3	77.2
Net income (loss)	$ 154.0	$ 125.3