| Cover | Sep. 12, 2024 |
| Cover [Abstract] | |
| Document Type | 6-K |
| Entity Central Index Key | 0001973239 |
| Document Fiscal Year Focus | 2025 |
| Document Period End Date | Sep. 12, 2024 |
| Amendment Flag | false |
| Entity Registrant Name | ARM HOLDINGS PLC /UK |
| Document Fiscal Period Focus | Q2 |
| Current Fiscal Year End Date | --03-31 |
