Earnings per share - Narrative (Details) - shares shares in Millions |
3 Months Ended | |
|---|---|---|
Dec. 31, 2025 |
Dec. 31, 2024 |
|
| Restricted Stock Units (RSUs) | ||
| Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] | ||
| Antidilutive securities excluded from computation of earnings per share, amount | 1.6 | |
| Performance Shares | ||
| Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] | ||
| Antidilutive securities excluded from computation of earnings per share, amount | 1.6 | 0.9 |