Goodwill, Capitalized Software and Other Intangible Assets 3 (Details) $ in Millions	9 Months Ended
Dec. 31, 2016 USD ($)
Goodwill activity by segment
Balance at March 31, 2016	$ 6,086
Acquisitions	38
Foreign currency translation adjustment	(6)
Balance at December 31, 2016	6,118
Mainframe Solutions
Goodwill activity by segment
Balance at March 31, 2016	4,178
Acquisitions	0
Foreign currency translation adjustment	0
Balance at December 31, 2016	4,178
Enterprise Solutions
Goodwill activity by segment
Balance at March 31, 2016	1,827
Acquisitions	38
Foreign currency translation adjustment	(6)
Balance at December 31, 2016	1,859
Services
Goodwill activity by segment
Balance at March 31, 2016	81
Acquisitions	0
Foreign currency translation adjustment	0
Balance at December 31, 2016	$ 81

Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=35741047&loc=d3e13816-109267

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6388280&loc=d3e13770-109266

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 45
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=64834752&loc=SL49117168-202975

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