Goodwill (Details) $ in Millions	9 Months Ended
Dec. 31, 2018 USD ($)
Changes in the carrying amount of goodwill by segment [Roll Forward]
Balance as of March 31, 2018, net	$ 7,619
Acquisitions	242
Divestitures	(12)
Foreign currency translation	(256)
Balance as of December 31, 2018, net	7,593
GBS
Changes in the carrying amount of goodwill by segment [Roll Forward]
Balance as of March 31, 2018, net	4,531
Acquisitions	242
Divestitures	(12)
Foreign currency translation	(153)
Balance as of December 31, 2018, net	4,608
GIS
Changes in the carrying amount of goodwill by segment [Roll Forward]
Balance as of March 31, 2018, net	3,088
Acquisitions	0
Divestitures	0
Foreign currency translation	(103)
Balance as of December 31, 2018, net	$ 2,985

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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Amount of increase (decrease) from foreign currency translation adjustments and purchase accounting adjustments 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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