Acquisitions 2 (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended	6 Months Ended
	Sep. 30, 2016	Sep. 30, 2016
Unaudited pro forma combined financial information for the Company, Automic and Veracode as though combined as of beginning of fiscal year 2017
Total revenue	$ 1,069	$ 2,117
Net income	$ 184	$ 346
Basic income per common share (in dollars per share)	$ 0.44	$ 0.82
Diluted income per common share (in dollars per share)	$ 0.44	$ 0.82