Divestitures 1 (Details) - USD ($) $ in Millions	12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2016
Income from discontinued operations
Income from discontinued operations, net of tax	$ 0	$ 0	$ 14
Discontinued Operations
Income from discontinued operations
Total revenue			27
Income from operations of discontinued components, net of tax expense of $7 million			12
Gain on disposal of discontinued components, net of tax			2
Income from discontinued operations, net of tax			14
Tax expense on income from operations of discontinued components			7
Discontinued Operations | Subscription and Maintenance
Income from discontinued operations
Total revenue			20
Discontinued Operations | Software Fees and Other
Income from discontinued operations
Total revenue			$ 7