v3.26.1
Derivative Instruments - Currency and Interest Rate Swap Contracts under Cash Flow Hedge Accounting (Parenthetical) (Detail)
$ in Thousands, ₩ in Millions
 12 Months Ended
Dec. 31, 2025
KRW (₩)
Dec. 31, 2024
KRW (₩)
Dec. 31, 2025
USD ($)
Nov. 13, 2024
Disclosure of detailed information about hedging instruments [line items]        
Derivative financial assets ₩ 310,146 ₩ 341,108    
Current derivative financial assets 6,945 119,500    
PS Marketing Corporation [Member]        
Disclosure of detailed information about hedging instruments [line items]        
Current derivative financial assets 5,830 5,385    
Sale Of Common Shares ₩ 2,169,379      
Proportion of ownership interest in subsidiary 70.00%      
SAPEON Inc [Member]        
Disclosure of detailed information about hedging instruments [line items]        
Derivative Financial Liability For Total Return Swap ₩ 50,000      
Derivative Financial Liability For Price Return Swap 555      
Written put options [member] | PS Marketing Corporation [Member]        
Disclosure of detailed information about hedging instruments [line items]        
Derivative financial assets 11,230      
SK Broadband Co., Ltd. [member]        
Disclosure of detailed information about hedging instruments [line items]        
Current derivative financial assets ₩ 91,824 ₩ 64,926    
Proportion of ownership interest in subsidiary 99.10% 99.10%    
SK Broadband Co., Ltd. [member] | Purchase Agreement [Member]        
Disclosure of detailed information about hedging instruments [line items]        
Cash flows used in obtaining control of subsidiaries or other businesses, classified as investing activities   ₩ 1,145,870    
Percentage of voting equity interests acquired 24.76%   24.76%  
SK Broadband Co., Ltd. [Member] | Purchase Agreement [Member]        
Disclosure of detailed information about hedging instruments [line items]        
Percentage of voting equity interests acquired       24.76%
Total return swaps [member]        
Disclosure of detailed information about hedging instruments [line items]        
Lease contract amount ₩ 270,000 ₩ 80,000    
Floating-to-fixed interest rate swap,Oct. 7,2024 [member]        
Disclosure of detailed information about hedging instruments [line items]        
Bonds face value | $     $ 300,000  
Fixed-to-fixed cross currency swap, Jul. 20, 2007 [member]        
Disclosure of detailed information about hedging instruments [line items]        
Bonds face value | $     400,000  
Floating-to-fixed cross-currency interest rate swap, Mar. 4, 2020 [member]        
Disclosure of detailed information about hedging instruments [line items]        
Bonds face value | $     $ 300,000  
Fixed-to-fixed cross currency swap, Jun. 28, 2023 [member]        
Disclosure of detailed information about hedging instruments [line items]        
Bonds face value ₩ 200,000