Accounting for Share-Based Compensation 1 (Details) - USD ($) $ in Millions	3 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Recognized share-based compensation
Share-based compensation expense before tax	$ 32	$ 29
Income tax benefit	(11)	(10)
Net share-based compensation expense	21	19
Costs of Licensing and Maintenance
Recognized share-based compensation
Share-based compensation expense before tax	2	2
Cost of Professional Services
Recognized share-based compensation
Share-based compensation expense before tax	1	1
Selling and Marketing
Recognized share-based compensation
Share-based compensation expense before tax	10	10
General and Administrative
Recognized share-based compensation
Share-based compensation expense before tax	12	11
Product Development and Enhancements
Recognized share-based compensation
Share-based compensation expense before tax	$ 7	$ 5