v3.26.1
Operating Segments Information - Summary of Geographical Information (Detail)
$ in Thousands, $ in Thousands
 12 Months Ended
Dec. 31, 2025
TWD ($)
Dec. 31, 2025
USD ($)
Dec. 31, 2024
TWD ($)
Dec. 31, 2023
TWD ($)
Dec. 31, 2025
USD ($)
Disclosure of geographical areas [line items]          
Operating revenue $ 645,387,710 $ 20,573,405 $ 595,409,585 $ 581,914,471  
Noncurrent assets, excluding financial instruments, post-employment benefit assets and deferred tax assets 522,480,091   416,919,169   $ 16,655,406
United States [Member]          
Disclosure of geographical areas [line items]          
Operating revenue 365,789,167 11,660,477 358,708,176 370,306,818  
Taiwan [member]          
Disclosure of geographical areas [line items]          
Operating revenue 115,968,173 3,696,786 89,274,839 70,492,517  
Noncurrent assets, excluding financial instruments, post-employment benefit assets and deferred tax assets 393,993,690   291,081,213   12,559,569
Asia [Member]          
Disclosure of geographical areas [line items]          
Operating revenue 97,824,930 3,118,423 82,989,985 75,316,422  
Europe [Member]          
Disclosure of geographical areas [line items]          
Operating revenue 64,908,598 2,069,130 63,429,243 65,026,966  
China [member]          
Disclosure of geographical areas [line items]          
Noncurrent assets, excluding financial instruments, post-employment benefit assets and deferred tax assets 72,078,909   70,968,611   2,297,702
Other geographical areas [member]          
Disclosure of geographical areas [line items]          
Operating revenue 896,842 $ 28,589 1,007,342 $ 771,748  
Noncurrent assets, excluding financial instruments, post-employment benefit assets and deferred tax assets $ 56,407,492   $ 54,869,345   $ 1,798,135