Stock-Based Compensation Expense (Detail) (USD $) In Millions	3 Months Ended		6 Months Ended
	Jul. 31, 2011	Jul. 31, 2010	Jul. 31, 2011	Jul. 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	$ 27.3	$ 21.0	$ 53.2	$ 45.3
Tax benefit	(5.8)	(5.3)	(13.4)	(12.1)
Stock-based compensation expense related to stock awards and ESP Plan purchases, net of tax	21.5	15.7	39.8	33.2
Cost of license and other revenue
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	1.0	0.7	1.9	1.5
Marketing and sales
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	11.3	9.2	23.1	19.8
Research and development
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	9.8	7.2	18.7	15.5
General and administrative
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 5.2	$ 3.9	$ 9.5	$ 8.5