Condensed Consolidating Financial Information - Condensed Consolidated Income Statement (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Jan. 28, 2017	Oct. 29, 2016	Jul. 30, 2016	Apr. 30, 2016	Jan. 30, 2016	Oct. 31, 2015	Aug. 01, 2015	May 02, 2015	Jan. 28, 2017	Jan. 30, 2016	Jan. 31, 2015
Condensed Income Statements, Captions [Line Items]
Sales	$ 2,269.9	$ 1,186.2	$ 1,373.4	$ 1,578.9	$ 2,392.6	$ 1,216.4	$ 1,410.6	$ 1,530.6	$ 6,408.4	$ 6,550.2	$ 5,736.3
Cost of sales									(4,047.6)	(4,109.8)	(3,662.1)
Gross margin	945.5	350.0	464.9	600.4	1,016.0	367.7	490.8	565.9	2,360.8	2,440.4	2,074.2
Selling, general and administrative expenses									(1,880.2)	(1,987.6)	(1,712.9)
Other operating income, net									282.6	250.9	215.3
Operating income									763.2	703.7	576.6
Intra-entity interest income (expense)									0.0	0.0
Interest expense, net									(49.4)	(45.9)	(36.0)
Income before income taxes									713.8	657.8	540.6
Income taxes									(170.6)	(189.9)	(159.3)
Equity in income of subsidiaries									0.0	0.0
Net income	$ 287.8	$ 14.8	$ 81.9	$ 146.8	$ 271.9	$ 15.0	$ 62.2	$ 118.8	543.2	467.9	381.3
Dividends on redeemable convertible preferred shares									(11.9)	0.0	0.0
Net income attributable to common shareholders									531.3	467.9	381.3
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
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									(1,116.6)	(1,045.4)	(1,529.0)
Net income									(1,116.6)	(1,045.4)	(1,529.0)
Dividends on redeemable convertible preferred shares									0.0	0.0	0.0
Net income attributable to common shareholders									(1,116.6)	(1,045.4)	(1,529.0)
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									(1.3)	(2.2)	(2.5)
Other operating income, net									0.0	0.0	0.0
Operating income									(1.3)	(2.2)	(2.5)
Intra-entity interest income (expense)									0.0	0.0	0.0
Interest expense, net									0.0	0.0	0.0
Income before income taxes									(1.3)	(2.2)	(2.5)
Income taxes									0.0	0.0	0.0
Equity in income of subsidiaries									544.5	470.1	383.8
Net income									543.2	467.9	381.3
Net income attributable to common shareholders									531.3	467.9	381.3
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
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	13.2
Interest expense, net									(19.8)	(19.9)	(13.9)
Income before income taxes									(1.0)	(1.1)	(0.7)
Income taxes									0.2	0.2	0.1
Equity in income of subsidiaries									0.0	0.0	0.0
Net income									(0.8)	(0.9)	(0.6)
Dividends on redeemable convertible preferred shares									0.0	0.0	0.0
Net income attributable to common shareholders									(0.8)	(0.9)	(0.6)
Guarantor Subsidiaries | Reportable Legal Entities
Condensed Income Statements, Captions [Line Items]
Sales									6,141.9	6,444.8	5,671.4
Cost of sales									(3,997.2)	(4,089.3)	(3,647.0)
Gross margin									2,144.7	2,355.5	2,024.4
Selling, general and administrative expenses									(1,775.1)	(1,942.7)	(1,683.6)
Other operating income, net									293.8	254.8	220.8
Operating income									663.4	667.6	561.6
Intra-entity interest income (expense)									(188.4)	(186.0)	(129.6)
Interest expense, net									(16.6)	(14.8)	(14.8)
Income before income taxes									458.4	466.8	417.2
Income taxes									(175.1)	(192.7)	(159.5)
Equity in income of subsidiaries									276.4	281.4	579.8
Net income									559.7	555.5	837.5
Dividends on redeemable convertible preferred shares									0.0	0.0	0.0
Net income attributable to common shareholders									559.7	555.5	837.5
Non-Guarantor Subsidiaries | Reportable Legal Entities
Condensed Income Statements, Captions [Line Items]
Sales									266.5	105.4	64.9
Cost of sales									(50.4)	(20.5)	(15.1)
Gross margin									216.1	84.9	49.8
Selling, general and administrative expenses									(103.8)	(42.7)	(26.8)
Other operating income, net									(11.2)	(3.9)	(5.5)
Operating income									101.1	38.3	17.5
Intra-entity interest income (expense)									169.6	167.2	116.4
Interest expense, net									(13.0)	(11.2)	(7.3)
Income before income taxes									257.7	194.3	126.6
Income taxes									4.3	2.6	0.1
Equity in income of subsidiaries									295.7	293.9	565.4
Net income									557.7	490.8	692.1
Dividends on redeemable convertible preferred shares									0.0	0.0	0.0
Net income attributable to common shareholders									$ 557.7	$ 490.8	$ 692.1