v3.26.1
Securities at amortized cost - Changes in carrying amount of securities at amortized cost (Details) - KRW (₩)
₩ in Millions
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Explanation of changes in gross carrying amount for securities at amortised cost [Line Items]      
Beginning balance ₩ 486,850,601    
Increase (decrease) in impairment loss securities at amortised cost [Abstract]      
Ending balance 549,165,419 ₩ 486,850,601  
Securities at amortized cost      
Explanation of changes in gross carrying amount for securities at amortised cost [Line Items]      
Beginning balance 19,213,940 24,010,113 ₩ 28,276,901
Increase (decrease) in impairment loss securities at amortised cost [Abstract]      
Transfer to 12-month expected credit losses 0 0 0
Transfer to lifetime expected credit losses 0 0 0
Transfer to credit-impaired financial assets 0 0 0
Acquisition 5,312,962 2,586,171 4,244,256
Disposal / Repayment (5,900,990) (7,634,677) (8,727,124)
Amortization based on effective interest method 111,965 93,318 167,219
Changes due to business combinations   10,000  
Others [1] (19,351) 149,015 48,861
Ending balance 18,718,526 19,213,940 24,010,113
Securities at amortized cost | Stage 1      
Explanation of changes in gross carrying amount for securities at amortised cost [Line Items]      
Beginning balance 19,213,940 24,010,113 28,276,901
Increase (decrease) in impairment loss securities at amortised cost [Abstract]      
Transfer to 12-month expected credit losses 0 0 0
Transfer to lifetime expected credit losses 0 0 0
Transfer to credit-impaired financial assets 0 0 0
Acquisition 5,312,962 2,586,171 4,244,256
Disposal / Repayment (5,900,990) (7,634,677) (8,727,124)
Amortization based on effective interest method 111,965 93,318 167,219
Changes due to business combinations   10,000  
Others [1] (19,351) 149,015 48,861
Ending balance 18,718,526 19,213,940 24,010,113
Securities at amortized cost | Lifetime expected credit losses | Stage 2      
Explanation of changes in gross carrying amount for securities at amortised cost [Line Items]      
Beginning balance 0 0 0
Increase (decrease) in impairment loss securities at amortised cost [Abstract]      
Transfer to 12-month expected credit losses 0 0 0
Transfer to lifetime expected credit losses 0 0 0
Transfer to credit-impaired financial assets 0 0 0
Acquisition 0 0 0
Disposal / Repayment 0 0 0
Amortization based on effective interest method 0 0 0
Others [1] 0 0 0
Ending balance 0 0 0
Securities at amortized cost | Lifetime expected credit losses | Stage 3      
Explanation of changes in gross carrying amount for securities at amortised cost [Line Items]      
Beginning balance 0 0 0
Increase (decrease) in impairment loss securities at amortised cost [Abstract]      
Transfer to 12-month expected credit losses 0 0 0
Transfer to lifetime expected credit losses 0 0 0
Transfer to credit-impaired financial assets 0 0 0
Acquisition 0 0 0
Disposal / Repayment 0 0 0
Amortization based on effective interest method 0 0 0
Others [1] 0 0 0
Ending balance ₩ 0 ₩ 0 ₩ 0
[1] Changes due to foreign currencies translation, etc.