Income Taxes Unrecognized Tax Benefits Reconciliation, Table (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Jan. 31, 2012	Jan. 31, 2011	Jan. 31, 2010
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Gross unrecognized tax benefits at the beginning of the fiscal year	$ 188.4	$ 178.2	$ 169.4
Increases for tax positions of prior years	0.4	2.0	3.1
Decreases for tax positions of prior years	(0.4)	(3.5)	(1.9)
Increases for tax positions related to the current year	14.3	13.9	11.1
Decreases for lapse of statute of limitations/audit settlements	(1.6)	(2.2)	(3.5)
Gross unrecognized tax benefits at the end of the fiscal year	$ 201.1	$ 188.4	$ 178.2