CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (USD $) In Millions, unless otherwise specified	12 Months Ended
	Jan. 31, 2013	Jan. 31, 2012	Jan. 31, 2011
Statement of Other Comprehensive Income [Abstract]
Net income	$ 247.4	$ 285.3	$ 212.0
Net (loss) gain on derivative instruments	(6.4)	10.0	(3.1)
Change in net unrealized gain on available-for-sale securities,	2.0	0.2	0.9
Change in unfunded portion of pension plans	(6.1)	1.2	(3.9)
Net change in cumulative foreign currency translation (loss) gain	(1.1)	(4.9)	9.0
Total other comprehensive (loss) income	(11.6)	6.5	2.9
Total comprehensive income	$ 235.8	$ 291.8	$ 214.9