v3.26.1
Contents of Significant Accounts - Summary of Interest Expense Capitalized (Detail) - TWD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Disclosure Of Detailed Information About Interest Expense Capitalized [Line Items]    
Interest expense capitalized $ 6,777 $ 13,560
Bottom of range [member]    
Disclosure Of Detailed Information About Interest Expense Capitalized [Line Items]    
Interest rates applied 1.64% 1.52%
Top of range [member]    
Disclosure Of Detailed Information About Interest Expense Capitalized [Line Items]    
Interest rates applied 1.81% 1.96%