v3.26.1
Related Party Transactions - Summary of Changes in Major Deposits Due to Customers with Related Parties (Details) - KRW (₩)
₩ in Millions
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
W Service Networks Co., Ltd.      
Reconciliation of changes in finance agreements from related parties [Abstract]      
Beginning balance ₩ 1,000 [1] ₩ 1,000 [1] ₩ 1,200
Changes in finance agreements from related parties [Abstract]      
Increase 0 2,000 1,000
Decrease 0 2,000 1,200
Ending balance [1] 1,000 1,000 1,000
Partner One Value Up I Private Equity Fund      
Reconciliation of changes in finance agreements from related parties [Abstract]      
Beginning balance   0 [1] 100
Changes in finance agreements from related parties [Abstract]      
Increase     0
Decrease     100
Ending balance [1]     0
Korea Credit Bureau Co., Ltd.      
Reconciliation of changes in finance agreements from related parties [Abstract]      
Beginning balance 0 0 [1] 3,000
Changes in finance agreements from related parties [Abstract]      
Increase 1,000   0
Decrease 0   3,000
Ending balance 1,000 [1] 0 0 [1]
Win Mortgage Co.,LTd.      
Reconciliation of changes in finance agreements from related parties [Abstract]      
Beginning balance 1,387 [1] 600  
Changes in finance agreements from related parties [Abstract]      
Increase   2,266  
Decrease   1,479  
Ending balance   1,387 [1] 600
One Mortgage      
Reconciliation of changes in finance agreements from related parties [Abstract]      
Beginning balance 1,387 600 [1] 0
Changes in finance agreements from related parties [Abstract]      
Increase 3,529   1,200
Decrease 3,564   600
Ending balance ₩ 1,352 [1] ₩ 1,387 ₩ 600 [1]
[1] Details of payment between related parties, demand deposit due to customers and etc. are excluded.