| Cover | 3 Months Ended | |
| Jul. 31, 2024 | Jun. 30, 2024 | |
| Cover [Abstract] | ||
| Document Type | 6-K | |
| Entity Central Index Key | 0001973239 | |
| Document Fiscal Year Focus | 2025 | |
| Document Period End Date | Jul. 31, 2024 | |
| Amendment Flag | false | |
| Entity Registrant Name | ARM HOLDINGS PLC /UK | |
| Current Fiscal Year End Date | --06-30 | |
| Document Fiscal Period Focus | Q1 |
