Stock-Based Compensation Expense (Detail) (USD $) In Millions	3 Months Ended
	Apr. 30, 2011	Apr. 30, 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	$ 25.9	$ 24.3
Tax benefit	(7.6)	(6.8)
Stock-based compensation expense related to stock awards and ESP Plan purchases, net of tax	18.3	17.5
Cost of license and other revenue
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	0.9	0.8
Marketing and sales
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	11.8	10.6
Research and development
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	8.9	8.3
General and administrative
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 4.3	$ 4.6