Income Taxes Provision for income taxes (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended								12 Months Ended
	Jan. 31, 2012	Oct. 31, 2011	Jul. 31, 2011	Apr. 30, 2011	Jan. 31, 2011	Oct. 31, 2010	Jul. 31, 2010	Apr. 30, 2010	Jan. 31, 2012	Jan. 31, 2011	Jan. 31, 2010
Federal
Current									$ 54.3	$ 16.0	$ 12.3
Deferred									(34.5)	(8.2)	(33.0)
State
Current									4.9	(1.5)	3.0
Deferred									1.3	7.4	7.1
Foreign
Current									55.9	48.4	34.1
Deferred									(4.3)	(2.1)	3.2
Income Tax Expense (Benefit)	$ 20.9	$ 18.5	$ 23.0	$ 15.2	$ 11.4	$ 18.1	$ 20.0	$ 10.5	$ 77.6	$ 60.0	$ 26.7