Financial instruments - Risk classification of trade accounts receivable (Details) - BRL (R$) R$ in Thousands |
Sep. 30, 2025 |
Dec. 31, 2024 |
Dec. 31, 2023 |
|---|---|---|---|
| Disclosure of internal credit grades [line items] | |||
| Expected credit losses | R$ 104,209 | R$ 97,934 | R$ 95,053 |
| Trade accounts receivable | |||
| Disclosure of internal credit grades [line items] | |||
| Expected credit losses | R$ 121,516 | R$ 30,300 | R$ 31,962 |