Accounting for Share-Based Compensation 1 (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Recognized share-based compensation
Share-based compensation expense before tax	$ 21	$ 16	$ 44	$ 41
Income tax benefit	(8)	(6)	(16)	(14)
Net share-based compensation expense	13	10	28	27
Costs of Licensing and Maintenance [Member]
Recognized share-based compensation
Share-based compensation expense before tax	1	1	1	2
Cost of Professional Services [Member]
Recognized share-based compensation
Share-based compensation expense before tax	1	1	2	2
Selling and Marketing [Member]
Recognized share-based compensation
Share-based compensation expense before tax	8	6	18	16
General and Administrative [Member]
Recognized share-based compensation
Share-based compensation expense before tax	7	4	15	12
Product Development and Enhancements [Member]
Recognized share-based compensation
Share-based compensation expense before tax	$ 4	$ 4	$ 8	$ 9