| Cover | 9 Months Ended | |
| Feb. 07, 2024 | Dec. 31, 2023 | |
| Cover [Abstract] | ||
| Document Type | 6-K | |
| Entity Central Index Key | 0001973239 | |
| Document Fiscal Year Focus | 2024 | |
| Document Period End Date | Feb. 07, 2024 | |
| Amendment Flag | false | |
| Entity Registrant Name | ARM HOLDINGS PLC /UK | |
| Current Fiscal Year End Date | --03-31 | |
| Document Fiscal Period Focus | Q3 |
