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Contents of Significant Accounts - Major Components of Income Tax Expense (Detail) $ in Thousands, $ in Thousands | 12 Months Ended
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Dec. 31, 2023 TWD ($) | Dec. 31, 2023 USD ($) | Dec. 31, 2022 TWD ($) | Dec. 31, 2021 TWD ($)
Current income tax expense (benefit): |  |  |  |
Current income tax charge | $ 6,426,598 |  | $ 17,582,039 | $ 7,088,975
Adjustments in respect of current income tax of prior periods | (217,891) |  | (585,941) | (150,260)
Deferred income tax expense (benefit): |  |  |  |
Deferred income tax related to origination and reversal of temporary differences | 2,239,309 |  | 2,276,015 | 407,280
Deferred income tax related to recognition and derecognition of tax losses and unused tax credits | 0 |  | 60,178 | 723,270
Adjustment of prior year's deferred income tax | (120,230) |  | 8,611 | (130,841)
Deferred income tax arising from write-down or reversal of write-down of deferred tax assets | (16,516) |  | (14,007) | (20,172)
Income tax expense recorded in profit or loss | 8,311,270 | $ 271,433 | 19,326,895 | 7,918,252
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 | (80,447) |  | (59,361) | 39,495
Unrealized gains or losses from equity instruments investments measured at fair value through other comprehensive income | (243,057) |  | (71,121) | (360,061)
Share of other comprehensive income (loss) of associates and joint ventures which will not be reclassified subsequently to profit or loss | (90,891) |  | 123,483 | (96,510)
Income tax related to items that will not be reclassified subsequently to profit or loss | (414,395) | (13,533) | (6,999) | (417,076)
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 | 386,660 |  | 883,238 | 23,175
Share of other comprehensive income (loss) of associates and joint ventures which may be reclassified subsequently to profit or loss | 3,768 |  | (23,672) | 6,763
Income tax related to items that may be reclassified subsequently to profit or loss | 390,428 | $ 12,751 | 859,566 | 29,938
Income tax charged directly to equity |  |  |  |
Disposal of parent company's stock by subsidiary recognized as treasury stock transactions | 0 |  |  | (203)
Adjustments of changes in net assets of associates and joint ventures accounted for using equity method | (1,117) |  | (2,720) | 22
Income tax charged directly to equity | $ (1,117) |  | $ (2,720) | $ (181)

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