v3.26.1
Contents of Significant Accounts - Leases (Detail)
$ in Thousands, $ in Thousands
 12 Months Ended
Dec. 31, 2025
TWD ($)
Dec. 31, 2024
TWD ($)
Dec. 31, 2025
USD ($)
Disclosure Of Lease By Lessee [Line Items]      
Depreciation $ 705,709 $ 698,651  
Right-of-use assets 7,476,034 8,039,015 $ 238,318
Current 624,825 636,357 19,918
Noncurrent 5,376,021 5,782,659 $ 171,375
Total 6,000,846 6,419,016  
Land [member]      
Disclosure Of Lease By Lessee [Line Items]      
Depreciation 375,604 377,882  
Right-of-use assets 5,416,282 5,755,484  
Buildings [member]      
Disclosure Of Lease By Lessee [Line Items]      
Depreciation 77,133 87,486  
Right-of-use assets 73,432 168,568  
Machinery and equipment [member]      
Disclosure Of Lease By Lessee [Line Items]      
Depreciation 239,391 220,734  
Right-of-use assets 1,952,668 2,082,479  
Transportation equipment [member]      
Disclosure Of Lease By Lessee [Line Items]      
Depreciation 9,773 10,852  
Right-of-use assets 13,918 12,561  
Other property, plant and equipment [member]      
Disclosure Of Lease By Lessee [Line Items]      
Depreciation 3,808 1,697  
Right-of-use assets $ 19,734 $ 19,923