Intangible Assets - Summary of Intangible Assets (Details) - USD ($) $ in Millions	Sep. 30, 2022	Mar. 31, 2022
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	$ 8,143	$ 8,502
Accumulated Amortization	5,259	5,124
Net Carrying Value	2,884	3,378
Software
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	3,981	4,063
Accumulated Amortization	3,103	3,039
Net Carrying Value	878	1,024
Customer related
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	3,873	4,148
Accumulated Amortization	2,048	1,995
Net Carrying Value	1,825	2,153
Other
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	289	291
Accumulated Amortization	108	90
Net Carrying Value	$ 181	$ 201

Accumulated amount of amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 30
-Section 50
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
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Amount before amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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Amount after amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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