Accounting for Share-Based Compensation 1 (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2017	Dec. 31, 2016
Recognized share-based compensation
Share-based compensation expense before tax	$ 28	$ 26	$ 89	$ 80
Income tax benefit	(7)	(8)	(27)	(26)
Net share-based compensation expense	21	18	62	54
Costs of Licensing and Maintenance
Recognized share-based compensation
Share-based compensation expense before tax	1	2	5	5
Cost of Professional Services
Recognized share-based compensation
Share-based compensation expense before tax	1	1	2	3
Selling and Marketing
Recognized share-based compensation
Share-based compensation expense before tax	9	9	29	28
General and Administrative
Recognized share-based compensation
Share-based compensation expense before tax	10	8	33	27
Product Development and Enhancements
Recognized share-based compensation
Share-based compensation expense before tax	$ 7	$ 6	$ 20	$ 17