Condensed Consolidating Financial Information - Condensed Consolidated Income Statement (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Feb. 03, 2018	Oct. 28, 2017	Jul. 29, 2017	Apr. 29, 2017	Jan. 28, 2017	Oct. 29, 2016	Jul. 30, 2016	Apr. 30, 2016	Feb. 03, 2018	Jan. 28, 2017	Jan. 30, 2016
Condensed Income Statements, Captions [Line Items]
Sales	$ 2,293.1	$ 1,156.9	$ 1,399.6	$ 1,403.4	$ 2,269.9	$ 1,186.2	$ 1,373.4	$ 1,578.9	$ 6,253.0	$ 6,408.4	$ 6,550.2
Cost of sales									(4,063.0)	(4,047.6)	(4,109.8)
Gross margin	919.8	321.1	457.9	491.2	945.5	350.0	464.9	600.4	2,190.0	2,360.8	2,440.4
Selling, general and administrative expenses									(1,872.2)	(1,880.2)	(1,987.6)
Credit transaction, net									1.3	0.0	0.0
Other operating income, net									260.8	282.6	250.9
Operating income									579.9	763.2	703.7
Intra-entity interest income (expense)									0.0	0.0
Interest expense, net									(52.7)	(49.4)	(45.9)
Income before income taxes									527.2	713.8	657.8
Income taxes									(7.9)	(170.6)	(189.9)
Equity in income of subsidiaries									0.0	0.0
Net income	$ 343.0	$ (12.1)	$ 85.2	$ 70.3	$ 287.8	$ 14.8	$ 81.9	$ 146.8	519.3	543.2	467.9
Dividends on redeemable convertible preferred shares									(32.9)	(11.9)	0.0
Net income attributable to common shareholders									486.4	531.3	467.9
Consolidation, Eliminations
Condensed Income Statements, Captions [Line Items]
Sales									0.0	0.0	0.0
Cost of sales									0.0	0.0	0.0
Gross margin									0.0	0.0	0.0
Selling, general and administrative expenses									0.0	0.0	0.0
Credit transaction, net									0.0
Other operating income, net									0.0	0.0	0.0
Operating income									0.0	0.0	0.0
Intra-entity interest income (expense)									0.0	0.0	0.0
Interest expense, net									0.0	0.0	0.0
Income before income taxes									0.0	0.0	0.0
Income taxes									0.0	0.0	0.0
Equity in income of subsidiaries									(983.8)	(1,116.6)	(1,045.4)
Net income									(983.8)	(1,116.6)	(1,045.4)
Dividends on redeemable convertible preferred shares									0.0	0.0	0.0
Net income attributable to common shareholders									(983.8)	(1,116.6)	(1,045.4)
Guarantor Subsidiaries | Reportable Legal Entities
Condensed Income Statements, Captions [Line Items]
Sales									5,866.6	6,141.9	6,444.8
Cost of sales									(3,926.6)	(3,997.2)	(4,089.3)
Gross margin									1,940.0	2,144.7	2,355.5
Selling, general and administrative expenses									(1,738.2)	(1,775.1)	(1,942.7)
Credit transaction, net									1.3
Other operating income, net									260.3	293.8	254.8
Operating income									463.4	663.4	667.6
Intra-entity interest income (expense)									(190.2)	(188.4)	(186.0)
Interest expense, net									(21.6)	(16.6)	(14.8)
Income before income taxes									251.6	458.4	466.8
Income taxes									(21.3)	(175.1)	(192.7)
Equity in income of subsidiaries									229.6	276.4	281.4
Net income									459.9	559.7	555.5
Dividends on redeemable convertible preferred shares									0.0	0.0	0.0
Net income attributable to common shareholders									459.9	559.7	555.5
Non-Guarantor Subsidiaries | Reportable Legal Entities
Condensed Income Statements, Captions [Line Items]
Sales									386.4	266.5	105.4
Cost of sales									(136.4)	(50.4)	(20.5)
Gross margin									250.0	216.1	84.9
Selling, general and administrative expenses									(132.1)	(103.8)	(42.7)
Credit transaction, net									0.0
Other operating income, net									0.4	(11.2)	(3.9)
Operating income									118.3	101.1	38.3
Intra-entity interest income (expense)									171.4	169.6	167.2
Interest expense, net									(11.2)	(13.0)	(11.2)
Income before income taxes									278.5	257.7	194.3
Income taxes									13.2	4.3	2.6
Equity in income of subsidiaries									233.1	295.7	293.9
Net income									524.8	557.7	490.8
Dividends on redeemable convertible preferred shares									0.0	0.0	0.0
Net income attributable to common shareholders									524.8	557.7	490.8
Signet Jewelers Limited | Reportable Legal Entities
Condensed Income Statements, Captions [Line Items]
Sales									0.0	0.0	0.0
Cost of sales									0.0	0.0	0.0
Gross margin									0.0	0.0	0.0
Selling, general and administrative expenses									(1.9)	(1.3)	(2.2)
Credit transaction, net									0.0
Other operating income, net									0.1	0.0	0.0
Operating income									(1.8)	(1.3)	(2.2)
Intra-entity interest income (expense)									0.0	0.0	0.0
Interest expense, net									0.0	0.0	0.0
Income before income taxes									(1.8)	(1.3)	(2.2)
Income taxes									0.0	0.0	0.0
Equity in income of subsidiaries									521.1	544.5	470.1
Net income									519.3	543.2	467.9
Net income attributable to common shareholders									486.4	531.3	467.9
Signet UK Finance plc | Reportable Legal Entities
Condensed Income Statements, Captions [Line Items]
Sales									0.0	0.0	0.0
Cost of sales									0.0	0.0	0.0
Gross margin									0.0	0.0	0.0
Selling, general and administrative expenses									0.0	0.0	0.0
Credit transaction, net									0.0
Other operating income, net									0.0	0.0	0.0
Operating income									0.0	0.0	0.0
Intra-entity interest income (expense)									18.8	18.8	18.8
Interest expense, net									(19.9)	(19.8)	(19.9)
Income before income taxes									(1.1)	(1.0)	(1.1)
Income taxes									0.2	0.2	0.2
Equity in income of subsidiaries									0.0	0.0	0.0
Net income									(0.9)	(0.8)	(0.9)
Dividends on redeemable convertible preferred shares									0.0	0.0	0.0
Net income attributable to common shareholders									$ (0.9)	$ (0.8)	$ (0.9)