Goodwill - Schedule of Goodwill (Details) - USD ($) $ in Millions	12 Months Ended
Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2019
Changes in the carrying amount of goodwill by segment [Roll Forward]
Goodwill, beginning balance	$ 2,017	$ 7,606
Acquisition related adjustments	15	1,358
Divestitures	(1,355)
Assets held for sale	(90)
Impairment Losses	0	(6,794)	$ 0
Foreign currency translation	54	(153)
Goodwill, gross	10,197	11,573
Accumulated impairment losses	(9,556)	(9,556)
Goodwill, ending balance	641	2,017	7,606
GBS
Changes in the carrying amount of goodwill by segment [Roll Forward]
Goodwill, beginning balance	2,017	4,599
Acquisition related adjustments	15	1,288
Divestitures	(1,355)
Assets held for sale	(90)
Impairment Losses		(3,789)
Foreign currency translation	54	(81)
Goodwill, gross	5,131	6,507
Accumulated impairment losses	(4,490)	(4,490)
Goodwill, ending balance	641	2,017	4,599
GIS
Changes in the carrying amount of goodwill by segment [Roll Forward]
Goodwill, beginning balance	0	3,007
Acquisition related adjustments	0	70
Divestitures	0
Assets held for sale	0
Impairment Losses		(3,005)
Foreign currency translation	0	(72)
Goodwill, gross	5,066	5,066
Accumulated impairment losses	(5,066)	(5,066)
Goodwill, ending balance	$ 0	$ 0	$ 3,007

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 in asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized resulting from a business combination.

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Amount of foreign currency translation gain (loss) which increases (decreases) an asset representing future economic benefits from other assets acquired in a business combination that are not individually identified and separately recognized.

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Amount before 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 accumulated impairment loss for 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 loss from the write-down of an asset representing the 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), classified as other, of an asset representing the future economic benefits from other assets acquired in a business combination that are not individually identified and separately recognized.

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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Amount of divestiture 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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