Condensed Statements Of Shareholders' Equity (USD $) In Millions, unless otherwise specified	Total	Common shares at par value	Additional paid-in- capital	Other reserves	Treasury shares	Retained earnings	Accumulated other comprehensive (loss) income
Balance at Jan. 31, 2015	$ 2,810.4	$ 15.7	$ 265.2	$ 0.4	$ (370.0)	$ 3,135.7	$ (236.6)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	118.8	0	0	0	0	118.8	0
Other comprehensive income	2.3	0	0	0	0	0	2.3
Dividends	(17.6)	0	0	0	0	(17.6)	0
Repurchase of common shares	(21.9)	0	0	0	(21.9)	0	0
Net settlement of equity based awards	(3.5)	0	(3.3)	0	(1.5)	1.3	0
Share options exercised	0.1	0	0	0	0.2	(0.1)	0
Share-based compensation expense	3.3	0	3.3	0	0	0	0
Balance at May. 02, 2015	$ 2,891.9	$ 15.7	$ 265.2	$ 0.4	$ (393.2)	$ 3,238.1	$ (234.3)