Condensed Consolidating Financial Information - Condensed Consolidated Statement of Cash Flows (Details) - USD ($) $ in Millions	12 Months Ended
	Jan. 28, 2017	Jan. 30, 2016	Jan. 31, 2015
Cash flows from operating activities:
Net cash provided by (used in) operating activities	$ 678.3	$ 443.3	$ 283.0
Investing activities
Purchase of property, plant and equipment	(278.0)	(226.5)	(220.2)
Investment in subsidiaries	0.0	0.0	0.0
Purchase of available-for-sale securities	(10.4)	(6.2)	(5.7)
Proceeds from available-for-sale securities	10.0	4.0	2.5
Net cash used in investing activities	(278.4)	(228.7)	(1,652.6)
Financing activities
Dividends paid on common shares	(75.6)	(67.1)	(55.3)
Intra-entity dividends paid	0.0	0.0	0.0
Proceeds from issuance of common shares	2.1	5.0	6.1
Proceeds from issuance of redeemable convertible preferred shares, net of issuance costs	611.3	0.0	0.0
Excess tax benefit from exercise of share awards	2.4	6.9	11.8
Proceeds from revolving credit facility	1,270.0	316.0	260.0
Repayments of revolving credit facility	(1,214.0)	(316.0)	(260.0)
Payment of debt issuance costs	(2.7)	0.0	(20.5)
Repurchase of common shares	(1,000.0)	(130.0)	(29.8)
Net settlement of equity based awards	(4.9)	(8.3)	(18.4)
Principal payments under capital lease obligations	(0.2)	(1.0)	(0.8)
Proceeds from (repayment of) short-term borrowings	(10.2)	(47.1)	39.4
Intra-entity activity, net	0.0	0.0	0.0
Net cash (used in) provided by financing activities	(438.2)	(266.6)	1,320.9
Cash and cash equivalents at beginning of period	137.7	193.6	247.6
Decrease in cash and cash equivalents	(38.3)	(52.0)	(48.7)
Effect of exchange rate changes on cash and cash equivalents	(0.7)	(3.9)	(5.3)
Cash and cash equivalents at end of period	98.7	137.7	193.6
Zale
Investing activities
Acquisition of business	0.0	0.0	(1,429.2)
Consolidation, Eliminations
Cash flows from operating activities:
Net cash provided by (used in) operating activities	(1,630.1)	(195.9)	(153.0)
Investing activities
Purchase of property, plant and equipment	0.0	0.0	0.0
Investment in subsidiaries	610.0	0.3	28.9
Purchase of available-for-sale securities	0.0	0.0	0.0
Proceeds from available-for-sale securities	0.0	0.0	0.0
Net cash used in investing activities	610.0	0.3	28.9
Financing activities
Dividends paid on common shares	0.0	0.0	0.0
Intra-entity dividends paid	1,630.1	195.9	953.0
Proceeds from issuance of common shares	(610.0)	(0.3)	(828.9)
Proceeds from issuance of redeemable convertible preferred shares, net of issuance costs	0.0	0.0	0.0
Excess tax benefit from exercise of share awards	0.0	0.0	0.0
Proceeds from revolving credit facility	0.0	0.0	0.0
Repayments of revolving credit facility	0.0	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
Net settlement of equity based awards	0.0	0.0	0.0
Principal payments under capital lease obligations	0.0	0.0	0.0
Proceeds from (repayment of) short-term borrowings	0.0	0.0	0.0
Intra-entity activity, net	0.0		0.0
Net cash (used in) provided by financing activities	1,020.1	195.6	124.1
Cash and cash equivalents at beginning of period	0.0	0.0	0.0
Decrease in cash and cash equivalents	0.0	0.0	0.0
Effect of exchange rate changes on cash and cash equivalents	0.0	0.0	0.0
Cash and cash equivalents at end of period	0.0	0.0	0.0
Consolidation, Eliminations | Zale
Investing activities
Acquisition of business	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	1,057.9	98.6	150.5
Investing activities
Purchase of property, plant and equipment	0.0	0.0	0.0
Investment in subsidiaries	(610.0)
Purchase of available-for-sale securities	0.0	0.0	0.0
Proceeds from available-for-sale securities	0.0	0.0	0.0
Net cash used in investing activities	(610.0)	0.0	0.0
Financing activities
Dividends paid on common shares	(75.6)	(67.1)	(55.3)
Intra-entity dividends paid	0.0	0.0	0.0
Proceeds from issuance of common shares	2.1	5.0	6.1
Proceeds from issuance of redeemable convertible preferred shares, net of issuance costs	611.3	0.0	0.0
Excess tax benefit from exercise of share awards	0.0	0.0	0.0
Proceeds from revolving credit facility	0.0	0.0	0.0
Repayments of revolving credit facility	0.0	0.0	0.0
Payment of debt issuance costs	0.0	0.0	0.0
Repurchase of common shares	(1,000.0)	(130.0)	(29.8)
Net settlement of equity based awards	(4.9)	(8.3)	(18.4)
Principal payments under capital lease obligations	0.0	0.0	0.0
Proceeds from (repayment of) short-term borrowings	0.0	0.0	0.0
Intra-entity activity, net	19.0	101.6	(52.4)
Net cash (used in) provided by financing activities	(448.1)	(98.8)	(149.8)
Cash and cash equivalents at beginning of period	1.9	2.1	1.4
Decrease in cash and cash equivalents	(0.2)	(0.2)	0.7
Effect of exchange rate changes on cash and cash equivalents	0.0	0.0	0.0
Cash and cash equivalents at end of period	1.7	1.9	2.1
Signet Jewelers Limited | Reportable Legal Entities | Zale
Investing activities
Acquisition of business	0.0	0.0	0.0
Signet UK Finance plc | Reportable Legal Entities
Cash flows from operating activities:
Net cash provided by (used in) operating activities	0.1	(0.1)	2.2
Investing activities
Purchase of property, plant and equipment	0.0	0.0	0.0
Investment in subsidiaries	0.0	0.0	0.0
Purchase of available-for-sale securities	0.0	0.0	0.0
Proceeds from available-for-sale securities	0.0	0.0	0.0
Net cash used in investing activities	0.0	0.0	0.0
Financing activities
Dividends paid on common shares	0.0	0.0	0.0
Intra-entity dividends paid	0.0	0.0	0.0
Proceeds from issuance of common shares		0.3	8.9
Proceeds from issuance of redeemable convertible preferred shares, net of issuance costs	0.0	0.0	0.0
Excess tax benefit from exercise of share awards	0.0	0.0	0.0
Proceeds from revolving credit facility	0.0	0.0	0.0
Repayments of revolving credit facility	0.0	0.0	0.0
Payment of debt issuance costs		0.0	(7.0)
Repurchase of common shares	0.0	0.0	0.0
Net settlement of equity based awards	0.0	0.0	0.0
Principal payments under capital lease obligations	0.0	0.0	0.0
Proceeds from (repayment of) short-term borrowings	0.0	0.0	0.0
Intra-entity activity, net	(0.1)	(0.2)	(402.4)
Net cash (used in) provided by financing activities	(0.1)	0.1	(2.1)
Cash and cash equivalents at beginning of period	0.1	0.1	0.0
Decrease in cash and cash equivalents		0.0	0.1
Effect of exchange rate changes on cash and cash equivalents	0.0	0.0	0.0
Cash and cash equivalents at end of period	0.1	0.1	0.1
Signet UK Finance plc | Reportable Legal Entities | Zale
Investing activities
Acquisition of business	0.0	0.0	0.0
Guarantor Subsidiaries | Reportable Legal Entities
Cash flows from operating activities:
Net cash provided by (used in) operating activities	724.8	325.7	166.6
Investing activities
Purchase of property, plant and equipment	(277.9)	(225.9)	(219.8)
Investment in subsidiaries		(0.3)	(18.9)
Purchase of available-for-sale securities	0.0	0.0	0.0
Proceeds from available-for-sale securities	0.0	0.0	0.0
Net cash used in investing activities	(277.9)	(226.2)	(1,669.8)
Financing activities
Dividends paid on common shares	0.0	0.0	0.0
Intra-entity dividends paid	(730.0)	(149.3)	(953.0)
Proceeds from issuance of common shares	610.0	0.0	10.0
Proceeds from issuance of redeemable convertible preferred shares, net of issuance costs	0.0	0.0	0.0
Excess tax benefit from exercise of share awards	2.4	6.9	11.8
Proceeds from revolving credit facility	1,270.0	316.0	260.0
Repayments of revolving credit facility	(1,214.0)	(316.0)	(260.0)
Payment of debt issuance costs	(2.1)	0.0	(10.7)
Repurchase of common shares	0.0	0.0	0.0
Net settlement of equity based awards	0.0	0.0	0.0
Principal payments under capital lease obligations	(0.2)	(1.0)	(0.8)
Proceeds from (repayment of) short-term borrowings	(10.2)	(47.1)	39.4
Intra-entity activity, net	(386.6)	54.9	1,957.9
Net cash (used in) provided by financing activities	(477.1)	(160.6)	1,444.6
Cash and cash equivalents at beginning of period	102.0	166.5	237.0
Decrease in cash and cash equivalents	(30.2)	(61.1)	(58.6)
Effect of exchange rate changes on cash and cash equivalents	(1.5)	(3.4)	(11.9)
Cash and cash equivalents at end of period	70.3	102.0	166.5
Guarantor Subsidiaries | Reportable Legal Entities | Zale
Investing activities
Acquisition of business			(1,431.1)
Non-Guarantor Subsidiaries | Reportable Legal Entities
Cash flows from operating activities:
Net cash provided by (used in) operating activities	525.6	215.0	116.7
Investing activities
Purchase of property, plant and equipment	(0.1)	(0.6)	(0.4)
Investment in subsidiaries			(10.0)
Purchase of available-for-sale securities	(10.4)	(6.2)	(5.7)
Proceeds from available-for-sale securities	10.0	4.0	2.5
Net cash used in investing activities	(0.5)	(2.8)	(11.7)
Financing activities
Dividends paid on common shares	0.0	0.0	0.0
Intra-entity dividends paid	(900.1)	(46.6)
Proceeds from issuance of common shares			810.0
Excess tax benefit from exercise of share awards	0.0	0.0	0.0
Proceeds from revolving credit facility	0.0	0.0	0.0
Repayments of revolving credit facility	0.0	0.0	0.0
Payment of debt issuance costs	(0.6)	0.0	(2.8)
Repurchase of common shares	0.0	0.0	0.0
Net settlement of equity based awards	0.0	0.0	0.0
Principal payments under capital lease obligations	0.0	0.0	0.0
Proceeds from (repayment of) short-term borrowings	0.0	0.0	0.0
Intra-entity activity, net	367.7	(156.3)	(1,503.1)
Net cash (used in) provided by financing activities	(533.0)	(202.9)	(95.9)
Cash and cash equivalents at beginning of period	33.7	24.9	9.2
Decrease in cash and cash equivalents	(7.9)	9.3	9.1
Effect of exchange rate changes on cash and cash equivalents	0.8	(0.5)	6.6
Cash and cash equivalents at end of period	26.6	33.7	24.9
Non-Guarantor Subsidiaries | Reportable Legal Entities | Zale
Investing activities
Acquisition of business			1.9
Senior Notes
Financing activities
Proceeds from debt	0.0	0.0	398.4
Senior Notes | Consolidation, Eliminations
Financing activities
Proceeds from debt	0.0	0.0	0.0
Senior Notes | Signet Jewelers Limited | Reportable Legal Entities
Financing activities
Proceeds from debt	0.0	0.0	0.0
Senior Notes | Signet UK Finance plc | Reportable Legal Entities
Financing activities
Proceeds from debt	0.0	0.0	398.4
Senior Notes | Non-Guarantor Subsidiaries | Reportable Legal Entities
Financing activities
Proceeds from debt	0.0	0.0	0.0
Term Loan
Financing activities
Proceeds from debt	0.0	0.0	400.0
Repayments of term loan	(16.4)	(25.0)	(10.0)
Term Loan | Consolidation, Eliminations
Financing activities
Proceeds from debt	0.0	0.0	0.0
Repayments of term loan	0.0	0.0	0.0
Term Loan | Signet Jewelers Limited | Reportable Legal Entities
Financing activities
Proceeds from debt	0.0	0.0	0.0
Repayments of term loan	0.0	0.0	0.0
Term Loan | Signet UK Finance plc | Reportable Legal Entities
Financing activities
Proceeds from debt	0.0	0.0	0.0
Repayments of term loan	0.0	0.0	0.0
Term Loan | Guarantor Subsidiaries | Reportable Legal Entities
Financing activities
Proceeds from debt			400.0
Repayments of term loan	(16.4)	(25.0)	(10.0)
Term Loan | Non-Guarantor Subsidiaries | Reportable Legal Entities
Financing activities
Proceeds from debt	0.0	0.0	0.0
Repayments of term loan	0.0	0.0	0.0
Securitization facility
Financing activities
Proceeds from debt	2,404.1	2,303.9	1,941.9
Repayments of term loan	(2,404.1)	(2,303.9)	(1,341.9)
Securitization facility | Consolidation, Eliminations
Financing activities
Proceeds from debt	0.0	0.0	0.0
Repayments of term loan	0.0	0.0	0.0
Securitization facility | Signet Jewelers Limited | Reportable Legal Entities
Financing activities
Proceeds from debt	0.0	0.0	0.0
Repayments of term loan	0.0	0.0	0.0
Securitization facility | Signet UK Finance plc | Reportable Legal Entities
Financing activities
Proceeds from debt	0.0	0.0	0.0
Repayments of term loan	0.0	0.0	0.0
Securitization facility | Non-Guarantor Subsidiaries | Reportable Legal Entities
Financing activities
Proceeds from debt	2,404.1	2,303.9	1,941.9
Repayments of term loan	$ (2,404.1)	$ (2,303.9)	$ (1,341.9)