Operating costs - Auditor fees (Details) - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Jun. 30, 2026 |
Jun. 30, 2025 |
Jun. 30, 2024 |
|
| Principal auditor | |||
| Disclosure of operating costs [line items] | |||
| Audit of these financials statements | $ 9.6 | $ 9.7 | $ 7.7 |
| Audit of financial statements of subsidiaries | 4.6 | 7.0 | 8.2 |
| Auditor's Remuneration For Audit Services Excluding Assurance Services | 14.2 | 16.7 | 15.9 |
| Audit related assurance services | 0.7 | 0.9 | 0.4 |
| Other Assurance Services | 1.4 | 1.2 | 1.7 |
| Auditors remuneration, Total | 16.3 | 18.8 | 18.0 |
| Auditor's remuneration for audit services | 15.1 | 18.0 | 17.0 |
| Auditors Remuneration For Audit Related Fees | 1.2 | 0.8 | 1.0 |
| Audit services in respect of employee pension plans | 0.6 | 0.6 | 0.4 |
| Other than principal auditor | |||
| Disclosure of operating costs [line items] | |||
| Auditor's remuneration for audit services | $ 2.9 | $ 0.5 | $ 0.1 |