v3.26.1
Provisions - Changes in Provisions (Detail) - KRW (₩)
₩ in Millions
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Disclosure of other provisions [line items]    
Beginning balance ₩ 120,060 ₩ 121,424
Increase 115,517 7,885
Utilization (6,701) (3,685)
Reversal (2,554) (3,296)
Changes in consolidation scope   (351)
Other (275) (1,917)
Ending balance 226,047 120,060
Current 145,953 50,016
Non-current 80,094 70,044
Provision for restoration [Member]    
Disclosure of other provisions [line items]    
Beginning balance 119,623 120,024
Increase 5,837 6,475
Utilization (6,330) (3,555)
Reversal (1,272) (1,053)
Changes in consolidation scope   (351)
Other (275) (1,917)
Ending balance 117,583 119,623
Current 37,502 49,579
Non-current 80,081 70,044
Emission allowance [Member]    
Disclosure of other provisions [line items]    
Beginning balance 437 1,182
Increase 1,641 1,410
Utilization (266) (130)
Reversal (1,282) (2,025)
Ending balance 530 437
Current 530 437
Other provisions [Member]    
Disclosure of other provisions [line items]    
Beginning balance   218
Increase 108,039  
Utilization (105)  
Reversal   ₩ (218)
Ending balance 107,934  
Current 107,921  
Non-current ₩ 13