Acquisitions 2 (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
Mar. 31, 2017	Mar. 31, 2016
Unaudited pro forma combined financial information for the Company, Automic and Veracode as though combined as of beginning of fiscal year 2016
Total revenue	$ 4,279	$ 4,215
Income from continuing operations	$ 706	$ 652
Basic income from continuing operations per common share (in dollars per share)	$ 1.68	$ 1.51
Diluted income from continuing operations per common share (in dollars per share)	$ 1.68	$ 1.51

Per basic share amount of pro forma income from continuing operations, after tax, as if the business combination had been completed at the beginning of a period.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (h)(2)-(3)
-URI http://asc.fasb.org/extlink&oid=79982066&loc=d3e1392-128463

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Per diluted share amount of pro forma income from continuing operations, after tax, as if the business combination had been completed at the beginning of a period.

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Amount after tax of pro forma income from continuing operations as if the business combination had been completed at the beginning of a period.

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The pro forma revenue for a period as if the business combination or combinations had been completed at the beginning of the period.

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