Stock-Based Compensation Expense (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Oct. 31, 2011	Oct. 31, 2010	Oct. 31, 2011	Oct. 31, 2010
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense related to stock awards and ESP Plan purchases	$ 25.6	$ 17.0	$ 78.8	$ 62.3
Tax benefit	(5.9)	(5.4)	(19.3)	(17.6)
Stock-based compensation expense related to stock awards and ESP Plan purchases, net of tax	19.7	11.6	59.5	44.7
Cost of license and other revenue
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	0.9	0.6	2.8	2.1
Marketing and sales
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	11.7	7.6	34.8	27.4
Research and development
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	8.9	5.7	27.6	21.2
General and administrative
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 4.1	$ 3.1	$ 13.6	$ 11.6