v3.26.1
Derivatives - Summary Of The Nominal Amount And The Average Interest And Currency Rate Of Hedging Instrument (Details)
₩ in Millions
12 Months Ended
Dec. 31, 2025
USD ($)
Dec. 31, 2024
USD ($)
EUR (€)
KRW (₩)
Dec. 31, 2025
KRW (₩)
Dec. 31, 2025
EUR (€)
Dec. 31, 2025
AUD ($)
Dec. 31, 2025
GBP (£)
Dec. 31, 2025
SEK (kr)
Dec. 31, 2025
JPY (¥)
Dec. 31, 2025
CAD ($)
Foreign currencies translation risk and interest rate risk | Currency swap | USD                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument   870,000,000              
Foreign currencies translation risk and interest rate risk | Currency swap | USD | 1 year or less                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument   0              
Foreign currencies translation risk and interest rate risk | Currency swap | USD | 1 to 5 years                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument   870,000,000              
Foreign currencies translation risk and interest rate risk | Currency swap | USD | More than 5 years                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument   0              
Foreign currencies translation risk | Currency swap | USD                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument   100,000,000              
Foreign currencies translation risk | Currency swap | USD | 1 year or less                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument   0              
Foreign currencies translation risk | Currency swap | USD | 1 to 5 years                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument   100,000,000              
Foreign currencies translation risk | Currency swap | USD | More than 5 years                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument   0              
Foreign currencies translation risk | Currency swap | EUR                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument | €   194,780,000              
Foreign currencies translation risk | Currency swap | EUR | 1 year or less                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument | €   0              
Foreign currencies translation risk | Currency swap | EUR | 1 to 5 years                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument | €   194,780,000              
Foreign currencies translation risk | Currency swap | EUR | More than 5 years                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument | €   0              
For fair value hedging | Interest rate risk | Interest rate swap | USD                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument 2,650,000,000 2,675,000,000              
Description of average rate of interest rate risk hedging instrument Fixed 3.47% receipt and (C.SOFR) + 1.06% paid Fixed 3.47% receipt and (C.SOFR) + 1.06% paid              
For fair value hedging | Interest rate risk | Interest rate swap | USD | 1 year or less                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument 550,000,000 25,000,000              
For fair value hedging | Interest rate risk | Interest rate swap | USD | 1 to 5 years                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument 2,100,000,000 2,650,000,000              
For fair value hedging | Interest rate risk | Interest rate swap | USD | More than 5 years                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument 0 0              
For fair value hedging | Interest rate risk | Interest rate swap | KRW                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument 290,000 155,000 290,000            
Description of average rate of interest rate risk hedging instrument Fixed 3.94% receipt and CD 3M + 0.01% paid Fixed 4.52% receipt and CD 3M + 0.02% paid              
For fair value hedging | Interest rate risk | Interest rate swap | KRW | 1 year or less                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument | ₩   0 0            
For fair value hedging | Interest rate risk | Interest rate swap | KRW | 1 to 5 years                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument | ₩     0            
For fair value hedging | Interest rate risk | Interest rate swap | KRW | More than 5 years                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument | ₩   155,000 290,000            
For fair value hedging | Foreign currencies translation risk | Currency forward | USD                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument 479,859,358                
Description of average rate of currency risk hedging instrument USD/KRW = 1,326.88                
For fair value hedging | Foreign currencies translation risk | Currency forward | USD | 1 year or less                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument 414,314,566                
For fair value hedging | Foreign currencies translation risk | Currency forward | USD | 1 to 5 years                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument 65,544,792                
For fair value hedging | Foreign currencies translation risk | Currency forward | USD | More than 5 years                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument 0                
For fair value hedging | Foreign currencies translation risk | Currency forward | AUD                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument 235,764,330       235,764,330        
Description of average rate of currency risk hedging instrument AUD/KRW = 874.06                
For fair value hedging | Foreign currencies translation risk | Currency forward | AUD | 1 year or less                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument         109,214,330        
For fair value hedging | Foreign currencies translation risk | Currency forward | AUD | 1 to 5 years                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument         126,550,000        
For fair value hedging | Foreign currencies translation risk | Currency forward | AUD | More than 5 years                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument         0        
For fair value hedging | Foreign currencies translation risk | Currency forward | EUR                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument 72,961,301     72,961,301          
Description of average rate of currency risk hedging instrument EUR/KRW = 1,498.43                
For fair value hedging | Foreign currencies translation risk | Currency forward | EUR | 1 year or less                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument | €       0          
For fair value hedging | Foreign currencies translation risk | Currency forward | EUR | 1 to 5 years                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument | €       72,961,301          
For fair value hedging | Foreign currencies translation risk | Currency forward | EUR | More than 5 years                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument | €       0          
For fair value hedging | Foreign currencies translation risk | Currency forward | GBP                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument 15,700,000         15,700,000      
Description of average rate of currency risk hedging instrument GBP/KRW = 1,854.71                
For fair value hedging | Foreign currencies translation risk | Currency forward | GBP | 1 year or less                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument | £           15,700,000      
For fair value hedging | Foreign currencies translation risk | Currency forward | GBP | 1 to 5 years                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument | £           0      
For fair value hedging | Foreign currencies translation risk | Currency forward | GBP | More than 5 years                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument | £           0      
For fair value hedging | Foreign currencies translation risk | Currency forward | USD                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Description of average rate of currency risk hedging instrument USD/KRW = 1,373.60                
For fair value hedging | Foreign currencies translation risk | Currency forward | AUD                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Description of average rate of currency risk hedging instrument AUD/KRW = 864.44                
For cash flow hedging | Interest rate risk | Interest rate swap | KRW                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument 60,000 140,000 60,000            
Description of average rate of interest rate risk hedging instrument KRW CD+0.37% receipt, KRW 2.75% paid KRW CMS 5Y+0.46% receipt, 3.65% paid              
For cash flow hedging | Interest rate risk | Interest rate swap | KRW | 1 year or less                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument | ₩   140,000 0            
For cash flow hedging | Interest rate risk | Interest rate swap | KRW | 1 to 5 years                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument | ₩   0 60,000            
For cash flow hedging | Interest rate risk | Interest rate swap | KRW | More than 5 years                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument | ₩   0 0            
For cash flow hedging | Interest rate risk | Interest Forward | USD                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument 320,000,000                
Description of average rate of interest rate risk hedging instrument YTM 5.14%, YTM 5.20%, USD/KRW = 1,373.23                
For cash flow hedging | Interest rate risk | Interest Forward | USD | 1 year or less                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument 0                
For cash flow hedging | Interest rate risk | Interest Forward | USD | 1 to 5 years                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument 320,000,000                
For cash flow hedging | Interest rate risk | Interest Forward | USD | More than 5 years                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument 0                
For cash flow hedging | Interest rate risk | Interest Forward | KRW                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument | ₩     2,010,000            
Description of average rate of interest rate risk hedging instrument YTM 2.91%, YTM 1.42%                
For cash flow hedging | Interest rate risk | Interest Forward | KRW | 1 year or less                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument | ₩     1,630,000            
For cash flow hedging | Interest rate risk | Interest Forward | KRW | 1 to 5 years                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument | ₩     380,000            
For cash flow hedging | Interest rate risk | Interest Forward | KRW | More than 5 years                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument | ₩     0            
For cash flow hedging | Foreign currencies translation risk and interest rate risk | EUR                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Description of average rate of currency risk hedging instrument EUR 3.03% paid, KRW 3.18% receipt, EUR/KRW = 1,619.42                
For cash flow hedging | Foreign currencies translation risk and interest rate risk | Currency swap | USD                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument 806,833,334 870,000,000              
Description of average rate of currency risk hedging instrument USD 0% receipt, KRW 0% paid, USD/KRW = 0 USD 1M SOFR + 0% receipt, KRW 0% paid, USD/KRW = 0 USD 1M SOFR+0.93% receipt, KRW 3.79% paid, USD/KRW = 1,344.45              
For cash flow hedging | Foreign currencies translation risk and interest rate risk | Currency swap | USD | 1 year or less                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument 336,333,334                
For cash flow hedging | Foreign currencies translation risk and interest rate risk | Currency swap | USD | 1 to 5 years                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument 470,500,000                
For cash flow hedging | Foreign currencies translation risk and interest rate risk | Currency swap | USD | More than 5 years                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument 0                
For cash flow hedging | Foreign currencies translation risk and interest rate risk | Currency swap | AUD                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument 80,000,000       80,000,000        
Description of average rate of currency risk hedging instrument AUD 3.11% paid, KRW 1.55% receipt, AUD/KRW = 952.20                
For cash flow hedging | Foreign currencies translation risk and interest rate risk | Currency swap | AUD | 1 year or less                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument         80,000,000        
For cash flow hedging | Foreign currencies translation risk and interest rate risk | Currency swap | AUD | 1 to 5 years                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument         0        
For cash flow hedging | Foreign currencies translation risk and interest rate risk | Currency swap | AUD | More than 5 years                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument         0        
For cash flow hedging | Foreign currencies translation risk and interest rate risk | Currency swap | EUR                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument 166,900,000     166,900,000          
Description of average rate of currency risk hedging instrument USD/KRW = 1,402.05, USD/KRW = 1,355.00                
For cash flow hedging | Foreign currencies translation risk and interest rate risk | Currency swap | EUR | 1 year or less                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument | €       52,000,000          
For cash flow hedging | Foreign currencies translation risk and interest rate risk | Currency swap | EUR | 1 to 5 years                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument | €       114,900,000          
For cash flow hedging | Foreign currencies translation risk and interest rate risk | Currency swap | EUR | More than 5 years                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument | €       0          
For cash flow hedging | Foreign currencies translation risk and interest rate risk | Currency swap | JPY                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument 5,000,000,000             5,000,000,000  
Description of average rate of currency risk hedging instrument JPY 3.20% paid, KRW 4.45% receipt, JPY/KRW = 946.53                
For cash flow hedging | Foreign currencies translation risk and interest rate risk | Currency swap | JPY | 1 year or less                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument | ¥               0  
For cash flow hedging | Foreign currencies translation risk and interest rate risk | Currency swap | JPY | 1 to 5 years                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument | ¥               0  
For cash flow hedging | Foreign currencies translation risk and interest rate risk | Currency swap | JPY | More than 5 years                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument | ¥               5,000,000,000  
For cash flow hedging | Foreign currencies translation risk and interest rate risk | Currency swap | SEK                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument 599,000,000           599,000,000    
Description of average rate of currency risk hedging instrument SEK 1.88% paid, KRW 2.01% receipt, SEK/KRW = 140.55                
For cash flow hedging | Foreign currencies translation risk and interest rate risk | Currency swap | SEK | 1 year or less                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument | kr             380,000,000    
For cash flow hedging | Foreign currencies translation risk and interest rate risk | Currency swap | SEK | 1 to 5 years                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument | kr             219,000,000    
For cash flow hedging | Foreign currencies translation risk and interest rate risk | Currency swap | SEK | More than 5 years                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument | kr             0    
For cash flow hedging | Foreign currencies translation risk | Currency swap | USD                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument 657,884,000 100,000,000              
Description of average rate of currency risk hedging instrument USD 1.75% receipt, KRW 1.63% paid,USD 2.50% receipt, KRW 3.76% paid,USD/KRW = 1,138.50USD/KRW = 1,404.97 USD 1.75% receipt, KRW 1.63% paid, USD/KRW = 1,138.50              
For cash flow hedging | Foreign currencies translation risk | Currency swap | USD | 1 year or less                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument 130,000,000                
For cash flow hedging | Foreign currencies translation risk | Currency swap | USD | 1 to 5 years                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument 527,884,000                
For cash flow hedging | Foreign currencies translation risk | Currency swap | USD | More than 5 years                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument 0                
For cash flow hedging | Foreign currencies translation risk | Currency swap | AUD                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument 215,000,000       215,000,000        
Description of average rate of currency risk hedging instrument AUD 3.58% receipt, KRW 4.96% paid, AUD/KRW = 902.70                
For cash flow hedging | Foreign currencies translation risk | Currency swap | AUD | 1 year or less                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument         15,000,000        
For cash flow hedging | Foreign currencies translation risk | Currency swap | AUD | 1 to 5 years                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument         200,000,000        
For cash flow hedging | Foreign currencies translation risk | Currency swap | AUD | More than 5 years                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument         0        
For cash flow hedging | Foreign currencies translation risk | Currency swap | EUR                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument 1,206,780,000 194,780,000   1,206,780,000          
Description of average rate of currency risk hedging instrument EUR 1.98% receipt, KRW 3.40% paid,EUR 3.21% receipt, KRW 3.14% paid, EUR/KRW = 1,344.08EUR/KRW = 1,644.48 EUR 1.98% receipt, KRW 3.40% paid, EUR/KRW = 1,344.08              
For cash flow hedging | Foreign currencies translation risk | Currency swap | EUR | 1 year or less                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument | €       194,780,000          
For cash flow hedging | Foreign currencies translation risk | Currency swap | EUR | 1 to 5 years                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument | €       1,012,000,000          
For cash flow hedging | Foreign currencies translation risk | Currency swap | EUR | More than 5 years                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument | €       0          
For cash flow hedging | Foreign currencies translation risk | Currency swap | JPY                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument 65,000,000,000             65,000,000,000  
Description of average rate of currency risk hedging instrument JPY 4.46% receipt, KRW 3.10% paid, JPY/KRW = 9.42                
For cash flow hedging | Foreign currencies translation risk | Currency swap | JPY | 1 year or less                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument | ¥               0  
For cash flow hedging | Foreign currencies translation risk | Currency swap | JPY | 1 to 5 years                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument | ¥               21,500,000,000  
For cash flow hedging | Foreign currencies translation risk | Currency swap | JPY | More than 5 years                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument | ¥               43,500,000,000  
For cash flow hedging | Foreign currencies translation risk | Currency swap | CAD                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument 40,000,000               40,000,000
Description of average rate of currency risk hedging instrument CAD 4.46% receipt, KRW 4.60% paid, CAD/KRW = 1,062.00                
For cash flow hedging | Foreign currencies translation risk | Currency swap | CAD | 1 year or less                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument                 0
For cash flow hedging | Foreign currencies translation risk | Currency swap | CAD | 1 to 5 years                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument                 40,000,000
For cash flow hedging | Foreign currencies translation risk | Currency swap | CAD | More than 5 years                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument                 0
For cash flow hedging | Foreign currencies translation risk | Currency forward | USD                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument 1,698,449,733                
Description of average rate of currency risk hedging instrument USD/KRW = 1,343.49                
For cash flow hedging | Foreign currencies translation risk | Currency forward | USD | 1 year or less                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument 998,071,601                
For cash flow hedging | Foreign currencies translation risk | Currency forward | USD | 1 to 5 years                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument 700,378,132                
For cash flow hedging | Foreign currencies translation risk | Currency forward | USD | More than 5 years                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument 0                
For cash flow hedging | Foreign currencies translation risk | Currency forward | AUD                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument 259,970,000       259,970,000        
Description of average rate of currency risk hedging instrument AUD/KRW = 863.03                
For cash flow hedging | Foreign currencies translation risk | Currency forward | AUD | 1 year or less                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument         99,970,000        
For cash flow hedging | Foreign currencies translation risk | Currency forward | AUD | 1 to 5 years                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument         160,000,000        
For cash flow hedging | Foreign currencies translation risk | Currency forward | AUD | More than 5 years                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument         0        
For cash flow hedging | Foreign currencies translation risk | Currency forward | EUR                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument 607,322,500     607,322,500          
Description of average rate of currency risk hedging instrument EUR/KRW = 1,539.86                
For cash flow hedging | Foreign currencies translation risk | Currency forward | EUR | 1 year or less                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument | €       374,850,500          
For cash flow hedging | Foreign currencies translation risk | Currency forward | EUR | 1 to 5 years                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument | €       232,472,000          
For cash flow hedging | Foreign currencies translation risk | Currency forward | EUR | More than 5 years                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument | €       0          
Hedges of net investment in foreign operations | Exchange risk | Foreign currency denominated debentures (KRWUSD)                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Description of average rate of currency risk hedging instrument USD/KRW = 1,421.88                
Hedges of net investment in foreign operations | Exchange risk | Foreign currency denominated debentures (KRWUSD) | KRW/USD                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Description of average rate of currency risk hedging instrument   USD/KRW = 1,363.09              
Hedges of net investment in foreign operations | Exchange risk | Foreign currency bond (USD) | USD                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument 863,959,317 863,959,317              
Hedges of net investment in foreign operations | Exchange risk | Foreign currency bond (USD) | USD | 1 year or less                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument 0 191,568,880              
Hedges of net investment in foreign operations | Exchange risk | Foreign currency bond (USD) | USD | 1 to 5 years                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument 863,959,317 672,390,437              
Hedges of net investment in foreign operations | Exchange risk | Foreign currency bond (USD) | USD | More than 5 years                  
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]                  
Nominal amount of hedging instrument 0 0