Goodwill, Capitalized Software and Other Intangible Assets 3 (Details) $ in Millions	6 Months Ended
Sep. 30, 2018 USD ($)
Goodwill activity by segment
Balance at March 31, 2018	$ 6,804
Acquisitions	6
Foreign currency translation adjustment	(20)
Balance at September 30, 2018	6,790
Mainframe Solutions
Goodwill activity by segment
Balance at March 31, 2018	4,178
Acquisitions	0
Foreign currency translation adjustment	0
Balance at September 30, 2018	4,178
Enterprise Solutions
Goodwill activity by segment
Balance at March 31, 2018	2,545
Acquisitions	6
Foreign currency translation adjustment	(20)
Balance at September 30, 2018	2,531
Services
Goodwill activity by segment
Balance at March 31, 2018	81
Acquisitions	0
Foreign currency translation adjustment	0
Balance at September 30, 2018	$ 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.

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