Condensed consolidating financial information - Condensed consolidated statement of comprehensive income (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Aug. 01, 2015	Aug. 02, 2014	Aug. 01, 2015	Aug. 02, 2014
Condensed Statement of Comprehensive Income [Line Items]
Net income	$ 62.2	$ 58.0	$ 181.0	$ 154.6
Other comprehensive income (loss):
Foreign currency translation adjustments	(4.7)	(2.3)	2.8	7.3
Available-for-sale securities:
Unrealized loss	(0.2)	(0.2)	(0.3)	(0.2)
Cash flow hedges:
Unrealized (loss) gain	(5.5)	(0.1)	(11.4)	0.2
Reclassification adjustment for losses to net income	0.8	3.4	1.3	8.1
Pension plan:
Reclassification adjustment to net income for amortization of actuarial loss	0.7	0.4	1.4	0.8
Reclassification adjustment to net income for amortization of prior service (credits) costs	(0.5)	(0.4)	(0.9)	(0.7)
Total other comprehensive income (loss)	(9.4)	0.8	(7.1)	15.5
Total comprehensive income	52.8	58.8	173.9	170.1
Consolidation, Eliminations
Condensed Statement of Comprehensive Income [Line Items]
Net income	(114.8)	(116.1)	(387.1)	(385.1)
Other comprehensive income (loss):
Foreign currency translation adjustments	4.7	2.2	(2.8)	(6.9)
Available-for-sale securities:
Unrealized loss	0.2	0.2	0.3	0.2
Cash flow hedges:
Unrealized (loss) gain	5.5	0.1	11.4	(0.2)
Reclassification adjustment for losses to net income	(0.8)	(3.4)	(1.3)	(8.1)
Pension plan:
Reclassification adjustment to net income for amortization of actuarial loss	(0.7)	(0.4)	(1.4)	(0.8)
Reclassification adjustment to net income for amortization of prior service (credits) costs	0.5	0.4	0.9	0.7
Total other comprehensive income (loss)	9.4	(0.9)	7.1	(15.1)
Total comprehensive income	(105.4)	(117.0)	(380.0)	(400.2)
Signet Jewelers Limited | Reportable Legal Entities
Condensed Statement of Comprehensive Income [Line Items]
Net income	62.2	58.0	181.0	154.6
Other comprehensive income (loss):
Foreign currency translation adjustments	(4.7)	(2.3)	2.8	7.3
Available-for-sale securities:
Unrealized loss	(0.2)	(0.2)	(0.3)	(0.2)
Cash flow hedges:
Unrealized (loss) gain	(5.5)	(0.1)	(11.4)	0.2
Reclassification adjustment for losses to net income	0.8	3.4	1.3	8.1
Pension plan:
Reclassification adjustment to net income for amortization of actuarial loss	0.7	0.4	1.4	0.8
Reclassification adjustment to net income for amortization of prior service (credits) costs	(0.5)	(0.4)	(0.9)	(0.7)
Total other comprehensive income (loss)	(9.4)	0.8	(7.1)	15.5
Total comprehensive income	52.8	58.8	173.9	170.1
Signet UK Finance plc | Reportable Legal Entities
Condensed Statement of Comprehensive Income [Line Items]
Net income	(0.1)	(0.1)	(0.3)	(0.1)
Other comprehensive income (loss):
Foreign currency translation adjustments	0.0	0.0	0.0	0.0
Available-for-sale securities:
Unrealized loss	0.0	0.0	0.0	0.0
Cash flow hedges:
Unrealized (loss) gain	0.0	0.0	0.0	0.0
Reclassification adjustment for losses to net income	0.0	0.0	0.0	0.0
Pension plan:
Reclassification adjustment to net income for amortization of actuarial loss	0.0	0.0	0.0	0.0
Reclassification adjustment to net income for amortization of prior service (credits) costs	0.0	0.0	0.0	0.0
Total other comprehensive income (loss)	0.0	0.0	0.0	0.0
Total comprehensive income	(0.1)	(0.1)	(0.3)	(0.1)
Guarantor Subsidiaries | Reportable Legal Entities
Condensed Statement of Comprehensive Income [Line Items]
Net income	41.0	54.2	188.2	225.0
Other comprehensive income (loss):
Foreign currency translation adjustments	(1.5)	(2.6)	6.0	8.3
Available-for-sale securities:
Unrealized loss	0.0		0.0	0.0
Cash flow hedges:
Unrealized (loss) gain	(5.5)	(0.1)	(11.4)	0.2
Reclassification adjustment for losses to net income	0.8	3.4	1.3	8.1
Pension plan:
Reclassification adjustment to net income for amortization of actuarial loss	0.7	0.4	1.4	0.8
Reclassification adjustment to net income for amortization of prior service (credits) costs	(0.5)	(0.4)	(0.9)	(0.7)
Total other comprehensive income (loss)	(6.0)	0.7	(3.6)	16.7
Total comprehensive income	35.0	54.9	184.6	241.7
Non-Guarantor Subsidiaries | Reportable Legal Entities
Condensed Statement of Comprehensive Income [Line Items]
Net income	73.9	62.0	199.2	160.2
Other comprehensive income (loss):
Foreign currency translation adjustments	(3.2)	0.4	(3.2)	(1.4)
Available-for-sale securities:
Unrealized loss	(0.2)	(0.2)	(0.3)	(0.2)
Cash flow hedges:
Unrealized (loss) gain	0.0	0.0	0.0	0.0
Reclassification adjustment for losses to net income	0.0	0.0	0.0	0.0
Pension plan:
Reclassification adjustment to net income for amortization of actuarial loss	0.0	0.0	0.0	0.0
Reclassification adjustment to net income for amortization of prior service (credits) costs	0.0	0.0	0.0	0.0
Total other comprehensive income (loss)	(3.4)	0.2	(3.5)	(1.6)
Total comprehensive income	$ 70.5	$ 62.2	$ 195.7	$ 158.6