Accounting for Share-Based Compensation 1 (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Recognized share-based compensation
Share-based compensation expense before tax	$ 23	$ 22	$ 45	$ 42
Income tax benefit	(7)	(7)	(14)	(13)
Net share-based compensation expense	16	15	31	29
Costs of Licensing and Maintenance
Recognized share-based compensation
Share-based compensation expense before tax	1	1	3	2
Cost of Professional Services
Recognized share-based compensation
Share-based compensation expense before tax	1	1	2	2
Selling and Marketing
Recognized share-based compensation
Share-based compensation expense before tax	8	8	16	15
General and Administrative
Recognized share-based compensation
Share-based compensation expense before tax	9	7	16	13
Product Development and Enhancements
Recognized share-based compensation
Share-based compensation expense before tax	$ 4	$ 5	$ 8	$ 10