Condensed consolidating financial information - Condensed consolidated income statement (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Oct. 31, 2015	Nov. 01, 2014	Oct. 31, 2015	Nov. 01, 2014
Condensed Income Statements, Captions [Line Items]
Sales	$ 1,216.4	$ 1,177.9	$ 4,157.6	$ 3,459.9
Cost of sales	(848.7)	(832.0)	(2,733.2)	(2,297.8)
Gross margin	367.7	345.9	1,424.4	1,162.1
Selling, general and administrative expenses	(395.0)	(388.7)	(1,301.0)	(1,078.4)
Other operating income, net	60.9	53.5	187.2	161.2
Operating income	33.6	10.7	310.6	244.9
Intra-entity interest income (expense)	0.0	0.0	0.0	0.0
Interest expense, net	(11.7)	(12.6)	(33.8)	(28.1)
Income (loss) before income taxes	21.9	(1.9)	276.8	216.8
Income taxes	(6.9)	0.6	(80.8)	(63.5)
Equity in income of subsidiaries	0.0	0.0	0.0	0.0
Net income (loss)	15.0	(1.3)	196.0	153.3
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 (loss) 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	27.3	73.1	(359.8)	(312.0)
Net income (loss)	27.3	73.1	(359.8)	(312.0)
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	(0.4)	(0.8)	(1.6)	(1.6)
Other operating income, net	0.0	0.0	0.0	0.0
Operating income	(0.4)	(0.8)	(1.6)	(1.6)
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 (loss) before income taxes	(0.4)	(0.8)	(1.6)	(1.6)
Income taxes	0.0	0.0	0.0	0.0
Equity in income of subsidiaries	15.4	(0.5)	197.6	154.9
Net income (loss)	15.0	(1.3)	196.0	153.3
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	14.1	8.5
Interest expense, net	(5.2)	(5.0)	(15.0)	(8.9)
Income (loss) before income taxes	(0.5)	(0.3)	(0.9)	(0.4)
Income taxes	0.1	0.1	0.2	0.1
Equity in income of subsidiaries	0.0	0.0	0.0	0.0
Net income (loss)	(0.4)	(0.2)	(0.7)	(0.3)
Guarantor Subsidiaries | Reportable Legal Entities
Condensed Income Statements, Captions [Line Items]
Sales	1,197.4	1,161.1	4,099.7	3,412.3
Cost of sales	(844.4)	(828.9)	(2,719.6)	(2,287.9)
Gross margin	353.0	332.2	1,380.1	1,124.4
Selling, general and administrative expenses	(387.1)	(380.7)	(1,276.2)	(1,056.4)
Other operating income, net	61.8	56.9	186.0	162.9
Operating income	27.7	8.4	289.9	230.9
Intra-entity interest income (expense)	(46.7)	(43.3)	(139.8)	(85.1)
Interest expense, net	(3.8)	(5.2)	(10.7)	(14.8)
Income (loss) before income taxes	(22.8)	(40.1)	139.4	131.0
Income taxes	9.3	13.0	(65.4)	(56.2)
Equity in income of subsidiaries	(30.8)	(50.2)	69.9	72.9
Net income (loss)	(44.3)	(77.3)	143.9	147.7
Non-Guarantor Subsidiaries | Reportable Legal Entities
Condensed Income Statements, Captions [Line Items]
Sales	19.0	16.8	57.9	47.6
Cost of sales	(4.3)	(3.1)	(13.6)	(9.9)
Gross margin	14.7	13.7	44.3	37.7
Selling, general and administrative expenses	(7.5)	(7.2)	(23.2)	(20.4)
Other operating income, net	(0.9)	(3.4)	1.2	(1.7)
Operating income	6.3	3.1	22.3	15.6
Intra-entity interest income (expense)	42.0	38.6	125.7	76.6
Interest expense, net	(2.7)	(2.4)	(8.1)	(4.4)
Income (loss) before income taxes	45.6	39.3	139.9	87.8
Income taxes	(16.3)	(12.5)	(15.6)	(7.4)
Equity in income of subsidiaries	(11.9)	(22.4)	92.3	84.2
Net income (loss)	$ 17.4	$ 4.4	$ 216.6	$ 164.6