Condensed consolidating financial information - Condensed consolidated statement of cash flows (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Aug. 01, 2015	Aug. 02, 2014	Aug. 01, 2015	Aug. 02, 2014
Cash flows from operating activities:
Net cash provided by (used in) operating activities	$ 143.6	$ 110.4	$ 210.6	$ 183.9
Investing activities
Purchase of property, plant and equipment	(56.0)	(61.9)	(98.9)	(90.0)
Investment in subsidiaries	0.0		0.0	0.0
Purchase of available-for-sale securities	(0.5)	(1.2)	(1.9)	(1.2)
Proceeds from available-for-sale securities	0.1	1.0	3.6	1.0
Acquisition of Zale Corporation, net of cash acquired	0.0	(1,429.2)	0.0	(1,429.2)
Net cash used in investing activities	(56.4)	(1,491.3)	(97.2)	(1,519.4)
Financing activities
Dividends paid	(17.7)	(14.4)	(32.1)	(26.4)
Intra-entity dividends paid		0.0	0.0	0.0
Proceeds from issuance of common shares	0.1	1.0	0.2	2.0
Excess tax benefit from exercise of share awards	0.0	0.0	5.1	7.7
Proceeds from long-term debt	558.1	1,398.4	1,196.3	1,398.4
Repayments of long-term debt	(563.1)		(1,206.3)
Payment of debt issuance costs	0.0	(15.4)	0.0	(18.4)
Repurchase of common shares	(62.8)	(11.0)	(81.9)	(22.4)
Net settlement of equity based awards	0.4	0.2	(8.3)	(15.1)
Capital lease payments	(0.3)	(0.2)	(0.6)	(0.2)
Proceeds from (repayment of) short-term borrowings	35.0	(11.7)	(20.0)	(22.2)
Intra-entity activity, net	0.0	0.0	0.0	0.0
Net cash used in financing activities	(50.3)	1,346.9	(147.6)	1,303.4
Cash and cash equivalents at beginning of period	122.6	249.1	193.6	247.6
Increase (decrease) in cash and cash equivalents	36.9	(34.0)	(34.2)	(32.1)
Effect of exchange rate changes on cash and cash equivalents	0.3	(0.1)	0.4	(0.5)
Cash and cash equivalents at end of period	159.8	215.0	159.8	215.0
Consolidation, Eliminations
Cash flows from operating activities:
Net cash provided by (used in) operating activities		(50.0)		(50.0)
Investing activities
Purchase of property, plant and equipment	0.0	0.0	0.0	0.0
Investment in subsidiaries		7.4		7.4
Purchase of available-for-sale securities	0.0	0.0	0.0	0.0
Proceeds from available-for-sale securities	0.0	0.0	0.0	0.0
Acquisition of Zale Corporation, net of cash acquired		0.0	0.0	0.0
Net cash used in investing activities	0.0	7.4	0.0	7.4
Financing activities
Dividends paid	0.0	0.0	0.0	0.0
Intra-entity dividends paid		850.0	0.0	850.0
Proceeds from issuance of common shares		(807.4)	0.0	(807.4)
Excess tax benefit from exercise of share awards	0.0		0.0	0.0
Proceeds from long-term debt	0.0	0.0	0.0	0.0
Repayments of long-term debt	0.0		0.0
Payment of debt issuance costs		0.0	0.0	0.0
Repurchase of common shares	0.0	0.0	0.0	0.0
Net settlement of equity based awards	0.0	0.0	0.0	0.0
Capital lease payments	0.0	0.0	0.0	0.0
Proceeds from (repayment of) short-term borrowings	0.0	0.0	0.0	0.0
Intra-entity activity, net	0.0		0.0
Net cash used in financing activities	0.0	42.6	0.0	42.6
Cash and cash equivalents at beginning of period	0.0	0.0	0.0	0.0
Increase (decrease) in cash and cash equivalents	0.0	0.0	0.0	0.0
Effect of exchange rate changes on cash and cash equivalents	0.0	0.0	0.0	0.0
Cash and cash equivalents at end of period	0.0	0.0	0.0	0.0
Signet Jewelers Limited | Reportable Legal Entities
Cash flows from operating activities:
Net cash provided by (used in) operating activities	2.5	49.6	(0.9)	49.1
Investing activities
Purchase of property, plant and equipment	0.0	0.0	0.0	0.0
Investment in subsidiaries	0.0	0.0	0.0	0.0
Purchase of available-for-sale securities	0.0	0.0	0.0	0.0
Proceeds from available-for-sale securities	0.0	0.0	0.0	0.0
Acquisition of Zale Corporation, net of cash acquired		0.0	0.0	0.0
Net cash used in investing activities	0.0	0.0	0.0	0.0
Financing activities
Dividends paid	(17.7)	(14.4)	(32.1)	(26.4)
Intra-entity dividends paid		0.0	0.0	0.0
Proceeds from issuance of common shares	0.1	1.0	0.2	2.0
Excess tax benefit from exercise of share awards	0.0		0.0	0.0
Proceeds from long-term debt	0.0	0.0	0.0	0.0
Repayments of long-term debt	0.0		0.0
Payment of debt issuance costs		0.0	0.0	0.0
Repurchase of common shares	(62.8)	(11.0)	(81.9)	(22.4)
Net settlement of equity based awards	0.4	0.2	(8.3)	(15.1)
Capital lease payments	0.0	0.0	0.0	0.0
Proceeds from (repayment of) short-term borrowings	0.0	0.0	0.0	0.0
Intra-entity activity, net	76.8	(25.7)	121.1	12.8
Net cash used in financing activities	(3.2)	(49.9)	(1.0)	(49.1)
Cash and cash equivalents at beginning of period	0.9	1.7	2.1	1.4
Increase (decrease) in cash and cash equivalents	(0.7)	(0.3)	(1.9)	0.0
Effect of exchange rate changes on cash and cash equivalents	0.0	0.0	0.0	0.0
Cash and cash equivalents at end of period	0.2	1.4	0.2	1.4
Signet UK Finance plc | Reportable Legal Entities
Cash flows from operating activities:
Net cash provided by (used in) operating activities	(4.7)	3.8	0.2	3.8
Investing activities
Purchase of property, plant and equipment	0.0	0.0	0.0	0.0
Investment in subsidiaries	0.0	0.0	0.0	0.0
Purchase of available-for-sale securities	0.0	0.0	0.0	0.0
Proceeds from available-for-sale securities	0.0	0.0	0.0	0.0
Acquisition of Zale Corporation, net of cash acquired		0.0	0.0	0.0
Net cash used in investing activities	0.0	0.0	0.0	0.0
Financing activities
Dividends paid	0.0	0.0	0.0	0.0
Intra-entity dividends paid		0.0	0.0	0.0
Proceeds from issuance of common shares		7.4	0.0	7.4
Excess tax benefit from exercise of share awards	0.0		0.0	0.0
Proceeds from long-term debt		398.4	0.0	398.4
Repayments of long-term debt	0.0		0.0
Payment of debt issuance costs		(5.7)	0.0	(5.7)
Repurchase of common shares	0.0	0.0	0.0	0.0
Net settlement of equity based awards	0.0	0.0	0.0	0.0
Capital lease payments	0.0	0.0	0.0	0.0
Proceeds from (repayment of) short-term borrowings	0.0	0.0	0.0	0.0
Intra-entity activity, net	4.7	(403.9)	(0.2)	(403.9)
Net cash used in financing activities	4.7	(3.8)	(0.2)	(3.8)
Cash and cash equivalents at beginning of period	0.1	0.0	0.1	0.0
Increase (decrease) in cash and cash equivalents	0.0	0.0	0.0	0.0
Effect of exchange rate changes on cash and cash equivalents	0.0	0.0	0.0	0.0
Cash and cash equivalents at end of period	0.1	0.0	0.1	0.0
Guarantor Subsidiaries | Reportable Legal Entities
Cash flows from operating activities:
Net cash provided by (used in) operating activities	102.8	76.9	157.2	139.3
Investing activities
Purchase of property, plant and equipment	(55.7)	(61.8)	(98.6)	(89.6)
Investment in subsidiaries		(7.4)		(7.4)
Purchase of available-for-sale securities	0.0		0.0	0.0
Proceeds from available-for-sale securities	0.0		0.0	0.0
Acquisition of Zale Corporation, net of cash acquired		(1,431.1)	0.0	(1,431.1)
Net cash used in investing activities	(55.7)	(1,500.3)	(98.6)	(1,528.1)
Financing activities
Dividends paid	0.0	0.0	0.0	0.0
Intra-entity dividends paid		(850.2)	0.0	(849.1)
Proceeds from issuance of common shares		0.0	0.0	0.0
Excess tax benefit from exercise of share awards			5.1	7.7
Proceeds from long-term debt		400.0	0.0	400.0
Repayments of long-term debt	(5.0)		(10.0)
Payment of debt issuance costs		(7.4)	0.0	(10.4)
Repurchase of common shares	0.0	0.0	0.0	0.0
Net settlement of equity based awards	0.0	0.0	0.0	0.0
Capital lease payments	(0.3)	(0.2)	(0.6)	(0.2)
Proceeds from (repayment of) short-term borrowings	35.0	(11.7)	(20.0)	(22.2)
Intra-entity activity, net	(44.3)	1,857.9	(56.8)	1,815.5
Net cash used in financing activities	(14.6)	1,388.4	(82.3)	1,341.3
Cash and cash equivalents at beginning of period	110.4	226.7	166.5	237.0
Increase (decrease) in cash and cash equivalents	32.5	(35.0)	(23.7)	(47.5)
Effect of exchange rate changes on cash and cash equivalents	0.1	(0.6)	0.2	1.6
Cash and cash equivalents at end of period	143.0	191.1	143.0	191.1
Non-Guarantor Subsidiaries | Reportable Legal Entities
Cash flows from operating activities:
Net cash provided by (used in) operating activities	43.0	30.1	54.1	41.7
Investing activities
Purchase of property, plant and equipment	(0.3)	(0.1)	(0.3)	(0.4)
Purchase of available-for-sale securities	(0.5)	(1.2)	(1.9)	(1.2)
Proceeds from available-for-sale securities	0.1	1.0	3.6	1.0
Acquisition of Zale Corporation, net of cash acquired		1.9		1.9
Net cash used in investing activities	(0.7)	1.6	1.4	1.3
Financing activities
Dividends paid	0.0	0.0	0.0	0.0
Intra-entity dividends paid		0.2	0.0	(0.9)
Proceeds from issuance of common shares		800.0		800.0
Excess tax benefit from exercise of share awards	0.0
Proceeds from long-term debt	558.1	600.0	1,196.3	600.0
Repayments of long-term debt	(558.1)		(1,196.3)
Payment of debt issuance costs		(2.3)	0.0	(2.3)
Repurchase of common shares	0.0	0.0	0.0	0.0
Net settlement of equity based awards	0.0	0.0	0.0	0.0
Capital lease payments	0.0	0.0	0.0	0.0
Proceeds from (repayment of) short-term borrowings	0.0	0.0	0.0	0.0
Intra-entity activity, net	(37.2)	(1,428.3)	(64.1)	(1,424.4)
Net cash used in financing activities	(37.2)	(30.4)	(64.1)	(27.6)
Cash and cash equivalents at beginning of period	11.2	20.7	24.9	9.2
Increase (decrease) in cash and cash equivalents	5.1	1.3	(8.6)	15.4
Effect of exchange rate changes on cash and cash equivalents	0.2	0.5	0.2	(2.1)
Cash and cash equivalents at end of period	$ 16.5	$ 22.5	$ 16.5	$ 22.5