Financial risk management - Additional Information (Details) - CNY (¥) ¥ in Millions |
6 Months Ended | ||
|---|---|---|---|
Jun. 30, 2026 |
Jun. 30, 2025 |
Dec. 31, 2025 |
|
| Financial Risk Management [Line Items] | |||
| Equity investments | ¥ 19,147 | ¥ 26,231 | |
| Current investments | 123 | 0 | |
| Fair Value Measurement With Unobservable Inputs Reconciliation Transfers Net | 0 | ¥ 0 | |
| Level 1 Hierarchy | |||
| Financial Risk Management [Line Items] | |||
| Equity investments | 19,131 | 26,217 | |
| Level 3 Hierarchy | |||
| Financial Risk Management [Line Items] | |||
| Equity investments | 16 | 14 | |
| Other current investment | 1,006 | 386 | |
| Current investments | ¥ 123 | ¥ 0 | |