v3.25.2
Expected credit loss measurement - ECL-relevant balance sheet and off-balance sheet positions including ECL allowances and provisions (Narrative) (Detail)
 3 Months Ended
Jun. 30, 2025
Mar. 31, 2025
Dec. 31, 2024
Disclosure Of Provision Matrix [Line Items]      
ECL coverage 0.30% 0.28% 0.27%
Stage 1 and 2 positions      
Disclosure Of Provision Matrix [Line Items]      
ECL coverage 0.11% 0.10% 0.10%
Increase decrease in ECL coverage 0.01%    
Allowance for expected credit loss | On-balance sheet      
Disclosure Of Provision Matrix [Line Items]      
ECL coverage 0.37% 0.36% 0.35%
Allowance for expected credit loss | Real estate lending (on-balance sheet) | On-balance sheet      
Disclosure Of Provision Matrix [Line Items]      
ECL coverage 0.06% 0.06% 0.07%
Allowance for expected credit loss | Corporate lending (on-balance sheet) | On-balance sheet      
Disclosure Of Provision Matrix [Line Items]      
ECL coverage 3.14% 3.02% 2.78%
Allowance for expected credit loss | Stage 1 and 2 positions | On-balance sheet      
Disclosure Of Provision Matrix [Line Items]      
ECL coverage 0.10% 0.10% 0.10%
Allowance for expected credit loss | Stage 1 and 2 positions | Real estate lending (on-balance sheet) | On-balance sheet      
Disclosure Of Provision Matrix [Line Items]      
ECL coverage 0.04% 0.04% 0.05%
Allowance for expected credit loss | Stage 1 and 2 positions | Corporate lending (on-balance sheet) | On-balance sheet      
Disclosure Of Provision Matrix [Line Items]      
ECL coverage 0.75% 0.72% 0.67%
Increase decrease in ECL coverage 0.03%