Shareholders' equity - Dividends (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								6 Months Ended
	Aug. 01, 2015	May. 02, 2015		Jan. 31, 2015	Aug. 02, 2014		May. 03, 2014	[1]	Aug. 01, 2015	Aug. 02, 2014
Equity [Abstract]
Common Stock, Dividends, Per Share, Declared	$ 0.22	$ 0.22	[1]		$ 0.18		$ 0.18		$ 0.44	$ 0.36
Dividends, Common Stock	$ 17.6	$ 17.6	[1],[2]		$ 14.4		$ 14.4		$ 35.2
Common Stock, Dividends, Per Share, Cash Paid		$ 0.22		$ 0.18
Dividends, Common Stock, Cash				$ 14.4
Dividends Payable	$ 17.6	$ 17.6			$ 14.4	[1],[2]			$ 17.6	$ 14.4	[1],[2]

[1] Signet’s dividend policy results in the dividend payment date being a quarter in arrears from the declaration date. As a result, the dividend declared in the fourth quarter of Fiscal 2015 of $0.18 per share was paid on February 26, 2015 in the aggregate of $14.4 million.

[2] The first quarter Fiscal 2016 $0.22 per share cash dividend was paid on May 27, 2015 in the aggregate amount of $17.6 million.