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Significant Subsequent Events - Additional Information (Detail)
$ in Millions, $ in Millions
 1 Months Ended
Jan. 31, 2022
TWD ($)
Dec. 31, 2021
TWD ($)
Dec. 31, 2021
USD ($)
Dec. 31, 2020
TWD ($)
Disclosure Of Nonadjusting Events After Reporting Period [Line Items]        
Unsecured domestic bonds   $ 27,000   $ 20,000
Investments accounted for using equity method   $ 7,137 $ 257 $ 6,695
Issuance of Unsecured Domestic Bonds [Member]        
Disclosure Of Nonadjusting Events After Reporting Period [Line Items]        
Unsecured domestic bonds $ 10,000      
Issuance Period 10 years      
Taiwania Capital Buffalo Fund VI, L.P. [Member]        
Disclosure Of Nonadjusting Events After Reporting Period [Line Items]        
Investments accounted for using equity method $ 600