v3.25.4
Goodwill and intangible assets - Impairment testing (Details) - USD ($)
$ in Millions
Dec. 31, 2025
Oct. 01, 2025
Dec. 31, 2024
Oct. 01, 2024
Disclosure of information for cash-generating units [line items]        
Goodwill and intangible assets $ 13,107   $ 12,384  
HSBC UK Bank plc | Hong Kong        
Disclosure of information for cash-generating units [line items]        
Carrying amount   $ 29,022    
Value in use   82,529    
HSBC UK Bank plc – WPB | Hong Kong        
Disclosure of information for cash-generating units [line items]        
Carrying amount       $ 12,785
Value in use       27,118
Goodwill        
Disclosure of information for cash-generating units [line items]        
Goodwill and intangible assets $ 4,419 1,800 $ 4,118 1,500
Goodwill | HSBC UK Bank plc | Hong Kong        
Disclosure of information for cash-generating units [line items]        
Goodwill and intangible assets   $ 2,639    
Discount rate   9.30%    
Growth rate beyond initial cash flow   2.10%    
Goodwill | HSBC UK Bank plc – WPB | Hong Kong        
Disclosure of information for cash-generating units [line items]        
Goodwill and intangible assets       $ 2,843
Discount rate       10.60%
Growth rate beyond initial cash flow       2.00%