Intangible Assets - Summary of Intangible Assets (Details) - USD ($) $ in Millions |
Dec. 31, 2022 |
Mar. 31, 2022 |
|---|---|---|
| Finite-Lived Intangible Assets [Line Items] | ||
| Gross Carrying Value | $ 8,199 | $ 8,502 |
| Accumulated Amortization | 5,458 | 5,124 |
| Net Carrying Value | 2,741 | 3,378 |
| Software | ||
| Finite-Lived Intangible Assets [Line Items] | ||
| Gross Carrying Value | 3,999 | 4,063 |
| Accumulated Amortization | 3,198 | 3,039 |
| Net Carrying Value | 801 | 1,024 |
| Customer related | ||
| Finite-Lived Intangible Assets [Line Items] | ||
| Gross Carrying Value | 3,891 | 4,148 |
| Accumulated Amortization | 2,140 | 1,995 |
| Net Carrying Value | 1,751 | 2,153 |
| Other | ||
| Finite-Lived Intangible Assets [Line Items] | ||
| Gross Carrying Value | 309 | 291 |
| Accumulated Amortization | 120 | 90 |
| Net Carrying Value | $ 189 | $ 201 |