v3.26.1
Contract Assets and Liabilities - Schedule of Performance Obligations (Detail) - KRW (₩)
₩ in Millions
Dec. 31, 2025
Dec. 31, 2024
Disclosure of performance obligations [line items]    
Contract liabilities ₩ 401,943 ₩ 229,706
Wireless service contracts [member]    
Disclosure of performance obligations [line items]    
Contract liabilities 21,807 20,275
Customer loyalty programs [member]    
Disclosure of performance obligations [line items]    
Contract liabilities 5,920 5,694
Fixed-line service contracts [member]    
Disclosure of performance obligations [line items]    
Contract liabilities 288,421 151,427
Other contract liabilities [member]    
Disclosure of performance obligations [line items]    
Contract liabilities 85,795 ₩ 52,310
Less than 1 year [member]    
Disclosure of performance obligations [line items]    
Contract liabilities 207,682  
Less than 1 year [member] | Wireless service contracts [member]    
Disclosure of performance obligations [line items]    
Contract liabilities 21,807  
Less than 1 year [member] | Customer loyalty programs [member]    
Disclosure of performance obligations [line items]    
Contract liabilities 4,221  
Less than 1 year [member] | Fixed-line service contracts [member]    
Disclosure of performance obligations [line items]    
Contract liabilities 95,859  
Less than 1 year [member] | Other contract liabilities [member]    
Disclosure of performance obligations [line items]    
Contract liabilities 85,795  
1 - 2 years [member]    
Disclosure of performance obligations [line items]    
Contract liabilities 23,627  
1 - 2 years [member] | Wireless service contracts [member]    
Disclosure of performance obligations [line items]    
Contract liabilities 0  
1 - 2 years [member] | Customer loyalty programs [member]    
Disclosure of performance obligations [line items]    
Contract liabilities 1,138  
1 - 2 years [member] | Fixed-line service contracts [member]    
Disclosure of performance obligations [line items]    
Contract liabilities 22,489  
1 - 2 years [member] | Other contract liabilities [member]    
Disclosure of performance obligations [line items]    
Contract liabilities 0  
More than 2 years [member]    
Disclosure of performance obligations [line items]    
Contract liabilities 170,634  
More than 2 years [member] | Wireless service contracts [member]    
Disclosure of performance obligations [line items]    
Contract liabilities 0  
More than 2 years [member] | Customer loyalty programs [member]    
Disclosure of performance obligations [line items]    
Contract liabilities 561  
More than 2 years [member] | Fixed-line service contracts [member]    
Disclosure of performance obligations [line items]    
Contract liabilities 170,073  
More than 2 years [member] | Other contract liabilities [member]    
Disclosure of performance obligations [line items]    
Contract liabilities ₩ 0