v3.26.1
Financial Risk Management - Fair Value and Carrying Amount of Financial Assets and Liabilities Including Fair Value Hierarchy (Detail) - KRW (₩)
₩ in Millions
Dec. 31, 2025
Dec. 31, 2024
Disclosure of detailed information about financial instruments [Line items]    
Borrowings ₩ 633,125 [1] ₩ 615,600
Debentures 8,213,904 [1] 8,511,280
Assets 7,975,070 7,488,373
Financial liabilities 13,996,145 15,913,626
Measured at fair value [member]    
Disclosure of detailed information about financial instruments [Line items]    
FVTPL 1,167,553 748,582
Derivative hedging instruments 201,262 270,797
FVOCI 3,025,988 1,739,133
Assets 4,394,803 2,758,512
FVTPL 5,782 2,689
Derivative hedging instruments 621 748
Financial liabilities 6,403 3,437
Not measured at fair value [member]    
Disclosure of detailed information about financial instruments [Line items]    
Borrowings 634,241 619,325
Debentures 8,183,670 8,582,255
Long-term payables – other 553,807 930,604
Financial liabilities 9,371,718 10,132,184
Carrying amount [member] | Measured at fair value [member]    
Disclosure of detailed information about financial instruments [Line items]    
FVTPL 1,167,553 748,582
Derivative hedging instruments 201,262 270,797
FVOCI 3,025,988 1,739,133
Assets 4,394,803 2,758,512
FVTPL 5,782 2,689
Derivative hedging instruments 621 748
Financial liabilities 6,403 3,437
Carrying amount [member] | Not measured at fair value [member]    
Disclosure of detailed information about financial instruments [Line items]    
Borrowings 633,125 615,600
Debentures 8,213,904 8,511,280
Long-term payables – other 547,961 907,720
Financial liabilities 9,394,990 10,034,600
Level 1 [member] | Measured at fair value [member]    
Disclosure of detailed information about financial instruments [Line items]    
FVTPL 0 0
Derivative hedging instruments 0 0
FVOCI 966,666 1,088,578
Assets 966,666 1,088,578
FVTPL 0 0
Derivative hedging instruments 0 0
Financial liabilities 0 0
Level 1 [member] | Not measured at fair value [member]    
Disclosure of detailed information about financial instruments [Line items]    
Borrowings 0 0
Debentures 0 0
Long-term payables – other 0 0
Financial liabilities 0 0
Level 2 [member] | Measured at fair value [member]    
Disclosure of detailed information about financial instruments [Line items]    
FVTPL 896,085 539,481
Derivative hedging instruments 201,262 270,797
FVOCI 0 171,967
Assets 1,097,347 982,245
FVTPL 26 0
Derivative hedging instruments 621 748
Financial liabilities 647 748
Level 2 [member] | Not measured at fair value [member]    
Disclosure of detailed information about financial instruments [Line items]    
Borrowings 634,241 619,325
Debentures 8,183,670 8,582,255
Long-term payables – other 553,807 930,604
Financial liabilities 9,371,718 10,132,184
Level 3 [member] | Measured at fair value [member]    
Disclosure of detailed information about financial instruments [Line items]    
FVTPL 271,468 209,101
Derivative hedging instruments 0 0
FVOCI 2,059,322 478,588
Assets 2,330,790 687,689
FVTPL 5,756 2,689
Derivative hedging instruments 0 0
Financial liabilities 5,756 2,689
Level 3 [member] | Not measured at fair value [member]    
Disclosure of detailed information about financial instruments [Line items]    
Borrowings 0 0
Debentures 0 0
Long-term payables – other 0 0
Financial liabilities ₩ 0 ₩ 0
[1] The contractual cash flow is amount that includes interest payables