Condensed consolidating financial information - Condensed consolidated statement of cash flows (Details) - USD ($) $ in Millions	3 Months Ended
	May 04, 2019	May 05, 2018
Cash flows from operating activities
Net cash provided by operating activities	$ 105.4	$ 27.9
Investing activities
Purchase of property, plant and equipment	(24.6)	(26.1)
Purchase of available-for-sale securities	(6.1)	(0.4)
Proceeds from available-for-sale securities	0.3	1.1
Net cash used in investing activities	(30.4)	(25.4)
Financing activities
Dividends paid on common shares	(19.2)	(18.8)
Dividends paid on redeemable convertible preferred shares	(7.8)	(7.8)
Intra-entity dividends paid		0.0
Repurchase of common shares	0.0	(60.0)
Proceeds from revolving credit facility		40.0
Repayments of revolving credit facility		(13.9)
Repayments of bank overdrafts	(37.3)	(13.9)
Other financing activities	(1.5)	(2.1)
Intra-entity activity, net	0.0	0.0
Net cash used in financing activities	(74.7)	(69.3)
Cash and cash equivalents at end of period	195.1	153.9
Increase (decrease) in cash and cash equivalents	0.3	(66.8)
Effect of exchange rate changes on cash and cash equivalents	(0.6)	(4.4)
Cash and cash equivalents at beginning of period	195.4	225.1
Consolidation, Eliminations
Cash flows from operating activities
Net cash provided by operating activities		(63.6)
Investing activities
Purchase of property, plant and equipment	0.0	0.0
Purchase of available-for-sale securities	0.0	0.0
Proceeds from available-for-sale securities	0.0	0.0
Net cash used in investing activities	0.0	0.0
Financing activities
Dividends paid on common shares	0.0	0.0
Dividends paid on redeemable convertible preferred shares	0.0	0.0
Intra-entity dividends paid		63.6
Repurchase of common shares		0.0
Proceeds from revolving credit facility		0.0
Repayments of revolving credit facility		0.0
Repayments of bank overdrafts	0.0
Other financing activities	0.0	0.0
Intra-entity activity, net	0.0	0.0
Net cash used in financing activities	0.0	63.6
Cash and cash equivalents at end of period	0.0	0.0
Increase (decrease) in cash and cash equivalents	0.0	0.0
Effect of exchange rate changes on cash and cash equivalents	0.0	0.0
Cash and cash equivalents at beginning of period	0.0	0.0
Guarantor Subsidiaries | Reportable Legal Entities
Cash flows from operating activities
Net cash provided by operating activities	9.3	(68.0)
Investing activities
Purchase of property, plant and equipment	(24.6)	(25.9)
Purchase of available-for-sale securities	0.0	0.0
Proceeds from available-for-sale securities	0.0	0.0
Net cash used in investing activities	(24.6)	(25.9)
Financing activities
Dividends paid on common shares	0.0	0.0
Dividends paid on redeemable convertible preferred shares	0.0	0.0
Intra-entity dividends paid		0.0
Repurchase of common shares		0.0
Proceeds from revolving credit facility		40.0
Repayments of revolving credit facility		(13.9)
Repayments of bank overdrafts	(37.3)
Other financing activities	0.0	0.0
Intra-entity activity, net	49.2	30.8
Net cash used in financing activities	3.0	50.2
Cash and cash equivalents at end of period	133.7	102.5
Increase (decrease) in cash and cash equivalents	(12.4)	(43.7)
Effect of exchange rate changes on cash and cash equivalents	(0.6)	(4.3)
Cash and cash equivalents at beginning of period	146.7	150.5
Non-Guarantor Subsidiaries | Reportable Legal Entities
Cash flows from operating activities
Net cash provided by operating activities	92.3	93.4
Investing activities
Purchase of property, plant and equipment		(0.2)
Purchase of available-for-sale securities	(6.1)	(0.4)
Proceeds from available-for-sale securities	0.3	1.1
Net cash used in investing activities	(5.8)	0.5
Financing activities
Dividends paid on common shares	0.0	0.0
Dividends paid on redeemable convertible preferred shares	0.0	0.0
Intra-entity dividends paid		(63.6)
Repurchase of common shares		0.0
Proceeds from revolving credit facility		0.0
Repayments of revolving credit facility		0.0
Repayments of bank overdrafts	0.0
Other financing activities	0.0	0.0
Intra-entity activity, net	(74.1)	(53.0)
Net cash used in financing activities	(74.1)	(116.6)
Cash and cash equivalents at end of period	60.9	50.0
Increase (decrease) in cash and cash equivalents	12.5	(22.7)
Effect of exchange rate changes on cash and cash equivalents		(0.1)
Cash and cash equivalents at beginning of period	48.4	72.8
Signet Jewelers Limited | Reportable Legal Entities
Cash flows from operating activities
Net cash provided by operating activities	(0.1)	61.2
Investing activities
Purchase of property, plant and equipment	0.0	0.0
Purchase of available-for-sale securities	0.0	0.0
Proceeds from available-for-sale securities	0.0	0.0
Net cash used in investing activities	0.0	0.0
Financing activities
Dividends paid on common shares	(19.2)	(18.8)
Dividends paid on redeemable convertible preferred shares	(7.8)	(7.8)
Intra-entity dividends paid		0.0
Repurchase of common shares		(60.0)
Proceeds from revolving credit facility		0.0
Repayments of bank overdrafts	0.0
Other financing activities	(1.5)	(2.1)
Intra-entity activity, net	28.8	27.1
Net cash used in financing activities	0.3	(61.6)
Cash and cash equivalents at end of period	0.4	1.3
Increase (decrease) in cash and cash equivalents	0.2	(0.4)
Effect of exchange rate changes on cash and cash equivalents	0.0	0.0
Cash and cash equivalents at beginning of period	0.2	1.7
Signet UK Finance plc | Reportable Legal Entities
Cash flows from operating activities
Net cash provided by operating activities	3.9	4.9
Investing activities
Purchase of property, plant and equipment	0.0	0.0
Purchase of available-for-sale securities	0.0	0.0
Proceeds from available-for-sale securities	0.0	0.0
Net cash used in investing activities	0.0	0.0
Financing activities
Dividends paid on common shares	0.0	0.0
Dividends paid on redeemable convertible preferred shares	0.0	0.0
Intra-entity dividends paid		0.0
Repurchase of common shares		0.0
Proceeds from revolving credit facility		0.0
Repayments of revolving credit facility		0.0
Repayments of bank overdrafts	0.0
Other financing activities	0.0	0.0
Intra-entity activity, net	(3.9)	(4.9)
Net cash used in financing activities	(3.9)	(4.9)
Cash and cash equivalents at end of period	0.1	0.1
Increase (decrease) in cash and cash equivalents	0.0	0.0
Effect of exchange rate changes on cash and cash equivalents	0.0	0.0
Cash and cash equivalents at beginning of period	0.1	0.1
Term Loan
Financing activities
Proceeds from term and bridge loans		(6.7)
Repayments of debt	(8.9)	(6.7)
Term Loan | Consolidation, Eliminations
Financing activities
Proceeds from term and bridge loans		0.0
Repayments of debt	0.0
Term Loan | Guarantor Subsidiaries | Reportable Legal Entities
Financing activities
Proceeds from term and bridge loans		(6.7)
Repayments of debt	(8.9)
Term Loan | Non-Guarantor Subsidiaries | Reportable Legal Entities
Financing activities
Proceeds from term and bridge loans		0.0
Repayments of debt	0.0
Term Loan | Signet Jewelers Limited | Reportable Legal Entities
Financing activities
Proceeds from term and bridge loans		0.0
Repayments of debt	0.0
Term Loan | Signet UK Finance plc | Reportable Legal Entities
Financing activities
Proceeds from term and bridge loans		$ 0.0
Repayments of debt	$ 0.0