v3.26.1
Contents of Significant Accounts - Major Components of Income Tax Expense (Detail)
$ in Thousands, $ in Thousands
 12 Months Ended
Dec. 31, 2025
TWD ($)
Dec. 31, 2025
USD ($)
Dec. 31, 2024
TWD ($)
Dec. 31, 2023
TWD ($)
Current income tax expense (benefit):        
Current income tax charge $ 6,058,083   $ 6,105,080 $ 6,426,598
Adjustments in respect of current income tax of prior periods 183,830   (124,430) (217,891)
Income tax expense affected by the Pillar Two legislation 151,151      
Deferred income tax expense (benefit):        
Deferred income tax related to origination and reversal of temporary differences 4,046,336   2,441,278 2,239,309
Deferred income tax related to recognition and derecognition of tax losses and unused tax credits (2,484,730)   (34,010) 0
Deferred income tax related to changes in tax rates (15,461)   68 0
Adjustment of prior year's deferred income tax (22,269)   (3,227) (120,230)
Deferred income tax arising from write-down or reversal of write-down of deferred tax assets (14,086)   (14,565) (16,516)
Income tax expense recorded in profit or loss 7,902,854 $ 251,924 8,370,194 8,311,270
Income tax related to components of other comprehensive income (loss), Items that will not be reclassified subsequently to profit or loss        
Remeasurements of defined benefit pension plans (29,021)   (37,690) (80,447)
Unrealized gains or losses from equity instruments investments measured at fair value through other comprehensive income 216,422   25,123 (243,057)
Share of other comprehensive income (loss) of associates and joint ventures which will not be reclassified subsequently to profit or loss (157,629)   28,783 (90,891)
Income tax related to items that will not be reclassified subsequently to profit or loss 29,772 949 16,216 (414,395)
Income tax related to components of other comprehensive income (loss), Items that may be reclassified subsequently to profit or loss        
Exchange differences on translation of foreign operations 508,067   153,317 386,660
Share of other comprehensive income (loss) of associates and joint ventures which may be reclassified subsequently to profit or loss 7,292   (24,317) 3,768
Income tax related to items that may be reclassified subsequently to profit or loss 515,359 $ 16,428 129,000 390,428
Income tax charged directly to equity        
Share of the net assets of the subsidiary (20,703)   0 0
Adjustments of changes in net assets of associates and joint ventures accounted for using equity method (4,556)   1,174 (1,117)
Deferred income tax charged directly to equity $ (25,259)   $ 1,174 $ (1,117)