v3.25.1
Subsequent events - (Details) - Subsequent event
$ / shares in Units, ¥ in Millions, $ in Millions
3 Months Ended 12 Months Ended
Mar. 17, 2025
USD ($)
$ / shares
Dec. 31, 2027
CNY (¥)
Dec. 31, 2026
CNY (¥)
O 2025 A Dividends      
Subsequent Event [Line Items]      
Dividend Declared date Mar. 17, 2025    
Dividend declared per share | $ / shares $ 1.47    
Dividends payable, Record date Jun. 17, 2025    
Cash dividends | $ $ 340    
Dividend payment date Jun. 30, 2025    
Forecast | Minimum | O 2026 A Dividends      
Subsequent Event [Line Items]      
Cash dividends | ¥     ¥ 30
Forecast | Minimum | O 2027 A Dividends      
Subsequent Event [Line Items]      
Cash dividends | ¥   ¥ 30  
American Depository Shares | O 2025 A Dividends      
Subsequent Event [Line Items]      
Dividend declared per share | $ / shares $ 1.47