Condensed consolidating financial information - Condensed consolidated balance sheet (Details) - USD ($) $ in Millions	Jul. 29, 2017	Jan. 28, 2017	Jul. 30, 2016	Jan. 30, 2016
Current assets:
Cash and cash equivalents	$ 119.1	$ 98.7	$ 118.7	$ 137.7
Accounts receivable, held for sale	1,055.6	0.0	0.0
Accounts receivable, net	664.5	1,858.0	1,650.6
Intra-entity receivables, net	0.0	0.0	0.0
Other receivables	91.2	95.9	66.9
Other current assets	128.5	136.3	152.0
Income taxes	1.8	4.4	1.4
Inventories	2,282.1	2,449.3	2,418.3
Total current assets	4,342.8	4,642.6	4,407.9
Non-current assets:
Property, plant and equipment, net	836.6	822.9	739.5
Goodwill	519.9	517.6	518.1	515.5
Intangible assets, net	413.9	417.0	424.7
Investment in subsidiaries	0.0		0.0
Intra-entity receivables, net	0.0		0.0
Other assets	165.1	165.1	158.0
Deferred tax assets	0.0	0.7	0.0
Retirement benefit asset	35.5	31.9	49.8
Total assets	6,313.8	6,597.8	6,298.0
Current liabilities:
Loans and overdrafts	939.4	91.1	238.6
Accounts payable	148.2	255.7	195.1
Intra-entity payables, net		0.0	0.0
Accrued expenses and other current liabilities	426.6	478.2	417.6
Deferred revenue	262.3	276.9	254.5
Income taxes	33.5	101.8	38.3
Total current liabilities	1,810.0	1,203.7	1,144.1
Non-current liabilities:
Long-term debt	705.3	1,317.9	1,330.5
Other liabilities	247.1	213.7	223.8
Deferred revenue	658.8	659.0	639.9
Deferred tax liabilities	103.3	101.4	79.8
Total liabilities	3,524.5	3,495.7	3,418.1
Shareholders’ equity:
Total shareholders’ equity	2,176.6	2,490.2	2,879.9
Total liabilities, redeemable convertible preferred shares and shareholders’ equity	6,313.8	6,597.8	6,298.0
Consolidation, Eliminations
Current assets:
Cash and cash equivalents	0.0	0.0	0.0	0.0
Accounts receivable, held for sale	0.0
Accounts receivable, net	0.0	0.0	0.0
Intra-entity receivables, net	(278.6)	(157.8)	(295.0)
Other receivables	0.0	0.0	0.0
Other current assets	0.0	0.0	0.0
Income taxes	0.0	0.0	0.0
Inventories	0.0	0.0	0.0
Total current assets	(278.6)	(157.8)	(295.0)
Non-current assets:
Property, plant and equipment, net	0.0		0.0
Goodwill	0.0		0.0
Intangible assets, net	0.0	0.0	0.0
Investment in subsidiaries	(3,626.7)	(4,430.1)	(4,036.3)
Intra-entity receivables, net	(3,840.0)	(4,050.0)	(4,060.0)
Other assets	0.0		0.0
Deferred tax assets	0.0		0.0
Retirement benefit asset	0.0		0.0
Total assets	(7,745.3)	(8,637.9)	(8,391.3)
Current liabilities:
Loans and overdrafts	0.0	0.0	0.0
Accounts payable	0.0	0.0	0.0
Intra-entity payables, net	(278.6)	(157.8)	(295.0)
Accrued expenses and other current liabilities	0.0	0.0	0.0
Deferred revenue	0.0	0.0	0.0
Income taxes	0.0	0.0	0.0
Total current liabilities	(278.6)	(157.8)	(295.0)
Non-current liabilities:
Long-term debt			0.0
Intra-entity payables, net	(3,840.0)	(4,050.0)	(4,060.0)
Other liabilities			0.0
Deferred revenue			0.0
Deferred tax liabilities		0.0	0.0
Total liabilities	(4,118.6)	(4,207.8)	(4,355.0)
Shareholders’ equity:
Total shareholders’ equity	(3,626.7)	(4,430.1)	(4,036.3)
Total liabilities, redeemable convertible preferred shares and shareholders’ equity	(7,745.3)	(8,637.9)	(8,391.3)
Signet Jewelers Limited | Reportable Legal Entities
Current assets:
Cash and cash equivalents	0.7	1.7	0.2	1.9
Accounts receivable, net	0.0	0.0	0.0
Intra-entity receivables, net	113.1	12.7	74.0
Other receivables	0.0	0.0	0.0
Other current assets		0.0	0.1
Income taxes	0.0	0.0	0.0
Inventories	0.0	0.0	0.0
Total current assets	113.8	14.4	74.3
Non-current assets:
Property, plant and equipment, net	0.0		0.0
Goodwill	0.0		0.0
Intangible assets, net	0.0	0.0	0.0
Investment in subsidiaries	2,703.1	3,117.6	2,835.5
Intra-entity receivables, net	0.0		0.0
Other assets	0.0		0.0
Deferred tax assets	0.0		0.0
Retirement benefit asset	0.0		0.0
Total assets	2,816.9	3,132.0	2,909.8
Current liabilities:
Loans and overdrafts	0.0	0.0	0.0
Accounts payable	0.0	0.0	0.0
Intra-entity payables, net	0.0	0.0	0.0
Accrued expenses and other current liabilities	27.6	29.9	29.9
Deferred revenue	0.0	0.0	0.0
Income taxes	0.0	0.0	0.0
Total current liabilities	27.6	29.9	29.9
Non-current liabilities:
Long-term debt			0.0
Other liabilities			0.0
Deferred revenue			0.0
Deferred tax liabilities		0.0	0.0
Total liabilities	27.6	29.9	29.9
Shareholders’ equity:
Total shareholders’ equity	2,176.6	2,490.2	2,879.9
Total liabilities, redeemable convertible preferred shares and shareholders’ equity	2,816.9	3,132.0	2,909.8
Signet UK Finance plc | Reportable Legal Entities
Current assets:
Cash and cash equivalents	0.1	0.1	0.1	0.1
Accounts receivable, net	0.0	0.0	0.0
Intra-entity receivables, net	3.1	0.0	0.0
Other receivables	0.0	0.0	0.0
Other current assets		0.0	0.0
Income taxes	0.0	0.0	0.0
Inventories	0.0	0.0	0.0
Total current assets	3.2	0.1	0.1
Non-current assets:
Property, plant and equipment, net	0.0	0.0	0.0
Goodwill	0.0	0.0	0.0
Intangible assets, net	0.0	0.0	0.0
Investment in subsidiaries	0.0	0.0	0.0
Intra-entity receivables, net	400.0	402.9	402.8
Other assets		0.0	0.0
Deferred tax assets	0.0	0.0	0.0
Retirement benefit asset	0.0	0.0	0.0
Total assets	403.2	403.0	402.9
Current liabilities:
Loans and overdrafts	(0.7)	(0.7)	(0.7)
Accounts payable	0.0	0.0	0.0
Intra-entity payables, net	0.0	0.0	0.0
Accrued expenses and other current liabilities	2.4	2.5	2.4
Deferred revenue	0.0	0.0	0.0
Income taxes	(0.1)	(0.2)	(0.1)
Total current liabilities	1.6	1.6	1.6
Non-current liabilities:
Long-term debt	394.8	394.3	393.9
Intra-entity payables, net		0.0	0.0
Other liabilities		0.0	0.0
Deferred revenue		0.0	0.0
Deferred tax liabilities		0.0	0.0
Total liabilities	396.4	395.9	395.5
Shareholders’ equity:
Total shareholders’ equity	6.8	7.1	7.4
Total liabilities, redeemable convertible preferred shares and shareholders’ equity	403.2	403.0	402.9
Guarantor Subsidiaries | Reportable Legal Entities
Current assets:
Cash and cash equivalents	90.2	70.3	83.8	102.0
Accounts receivable, held for sale	1,055.6
Accounts receivable, net	664.5	1,858.0	1,648.5
Intra-entity receivables, net	0.0	145.1	0.0
Other receivables	63.3	71.1	46.3
Other current assets	123.5	131.4	146.7
Income taxes	1.8	4.4	1.4
Inventories	2,214.7	2,371.8	2,342.5
Total current assets	4,213.6	4,652.1	4,269.2
Non-current assets:
Property, plant and equipment, net	832.6	818.5	734.6
Goodwill	516.3	514.0	514.5
Intangible assets, net	413.9	417.0	424.7
Investment in subsidiaries	532.8	721.6	675.2
Intra-entity receivables, net	0.0		0.0
Other assets	133.6	134.8	127.4
Deferred tax assets		0.6	0.0
Retirement benefit asset	35.5	31.9	49.8
Total assets	6,678.3	7,290.5	6,795.4
Current liabilities:
Loans and overdrafts	340.1	91.8	239.3
Accounts payable	142.7	248.2	192.5
Intra-entity payables, net	278.6		295.0
Accrued expenses and other current liabilities	375.9	429.2	371.5
Deferred revenue	262.3	275.5	254.5
Income taxes	30.1	115.5	38.4
Total current liabilities	1,429.7	1,160.2	1,391.2
Non-current liabilities:
Long-term debt	310.5	323.6	336.6
Intra-entity payables, net	3,840.0	4,050.0	4,060.0
Other liabilities	241.4	208.7	217.3
Deferred revenue	658.8	659.0	639.9
Deferred tax liabilities	103.3	101.4	80.0
Total liabilities	6,583.7	6,502.9	6,725.0
Shareholders’ equity:
Total shareholders’ equity	94.6	787.6	70.4
Total liabilities, redeemable convertible preferred shares and shareholders’ equity	6,678.3	7,290.5	6,795.4
Non-Guarantor Subsidiaries | Reportable Legal Entities
Current assets:
Cash and cash equivalents	28.1	26.6	34.6	$ 33.7
Accounts receivable, net			2.1
Intra-entity receivables, net	162.4		221.0
Other receivables	27.9	24.8	20.6
Other current assets	5.0	4.9	5.2
Income taxes	0.0		0.0
Inventories	67.4	77.5	75.8
Total current assets	290.8	133.8	359.3
Non-current assets:
Property, plant and equipment, net	4.0	4.4	4.9
Goodwill	3.6	3.6	3.6
Intangible assets, net	0.0	0.0	0.0
Investment in subsidiaries	390.8	590.9	525.6
Intra-entity receivables, net	3,440.0	3,647.1	3,657.2
Other assets	31.5	30.3	30.6
Deferred tax assets		0.1	0.0
Retirement benefit asset	0.0		0.0
Total assets	4,160.7	4,410.2	4,581.2
Current liabilities:
Loans and overdrafts	600.0	0.0	0.0
Accounts payable	5.5	7.5	2.6
Intra-entity payables, net	0.0	157.8	0.0
Accrued expenses and other current liabilities	20.7	16.6	13.8
Deferred revenue	0.0	1.4	0.0
Income taxes	3.5	(13.5)	0.0
Total current liabilities	629.7	169.8	16.4
Non-current liabilities:
Long-term debt		600.0	600.0
Other liabilities	5.7	5.0	6.5
Deferred revenue			0.0
Deferred tax liabilities		0.0	(0.2)
Total liabilities	635.4	774.8	622.7
Shareholders’ equity:
Total shareholders’ equity	3,525.3	3,635.4	3,958.5
Total liabilities, redeemable convertible preferred shares and shareholders’ equity	4,160.7	4,410.2	4,581.2
Series A Redeemable Convertible Preferred Stock
Non-current liabilities:
Series A redeemable convertible preferred shares	612.7	611.9	0.0
Series A Redeemable Convertible Preferred Stock | Consolidation, Eliminations
Non-current liabilities:
Series A redeemable convertible preferred shares	0.0	0.0	0.0
Series A Redeemable Convertible Preferred Stock | Signet Jewelers Limited | Reportable Legal Entities
Non-current liabilities:
Series A redeemable convertible preferred shares	612.7	611.9	0.0
Series A Redeemable Convertible Preferred Stock | Signet UK Finance plc | Reportable Legal Entities
Non-current liabilities:
Series A redeemable convertible preferred shares	0.0	0.0	0.0
Series A Redeemable Convertible Preferred Stock | Guarantor Subsidiaries | Reportable Legal Entities
Non-current liabilities:
Series A redeemable convertible preferred shares	0.0	0.0	0.0
Series A Redeemable Convertible Preferred Stock | Non-Guarantor Subsidiaries | Reportable Legal Entities
Non-current liabilities:
Series A redeemable convertible preferred shares	$ 0.0	$ 0.0	$ 0.0