Shareholders' equity - Share Repurchase (Details) (2013 Program, USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended
	May 02, 2015		May 03, 2014		Jun. 14, 2013
2013 Program
Class of Stock [Line Items]
Amount authorized					$ 350.0	[1]
Shares repurchased (shares)	160,298	[1]	126,468	[1]
Amount repurchased	21.9	[1]	12.9	[1]
Average repurchase price per share (usd per share)	$ 136.84	[1]	$ 102.10	[1]
Remaining authorized repurchase amount	243.7
Shares Repurchased But Not Yet Settled and Paid	$ 2.8		$ 1.5

[1] On June 14, 2013, the Board authorized the repurchase of up to $350 million of Signet’s common shares (the “2013 Program”). The 2013 Program may be suspended or discontinued at any time without notice. The 2013 Program had $243.7 million remaining as of May 2, 2015.