Common Shares, Treasury Shares, Reserves and Dividends - Dividends (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended												12 Months Ended
	Jan. 28, 2017	Oct. 29, 2016	Jul. 30, 2016	Apr. 30, 2016	Jan. 30, 2016	Oct. 31, 2015	Aug. 01, 2015	May 02, 2015	Jan. 31, 2015	Nov. 01, 2014	Aug. 02, 2014	May 03, 2014	Jan. 28, 2017	Jan. 30, 2016	Jan. 31, 2015
Equity [Abstract]
Dividends declared per common share (usd per share)	$ 0.26	$ 0.26	$ 0.26	$ 0.26	$ 0.22	$ 0.22	$ 0.22	$ 0.22	$ 0.18	$ 0.18	$ 0.18	$ 0.18	$ 1.04	$ 0.88	$ 0.72
Cash dividend per share (usd per share)													$ 1.04	$ 0.88	$ 0.72
Total dividends	$ 17.7	$ 18.1	$ 19.7	$ 20.4	$ 17.5	$ 17.5	$ 17.6	$ 17.6	$ 14.4	$ 14.5	$ 14.4	$ 14.4	$ 75.9	$ 70.2	$ 57.7
Dividends on preferred shares	$ 17.7				$ 17.5								$ 17.7	$ 17.5