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Contents of Significant Accounts - Reconciliation of Liabilities Arising from Financing Activities (Detail) - TWD ($) $ in Thousands | 12 Months Ended
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Dec. 31, 2024 | Dec. 31, 2023 | Dec. 31, 2022
Short-term loans [member] |  |  |  |  |  |  |
Disclosure of reconciliation of liabilities arising from financing activities [line items] |  |  |  |  |  |  |
Beginning balance |  | $ 13,530,000 |  | $ 0 |  | $ 1,924,124 |
Cash Flows |  | (5,015,000) |  | 13,530,000 |  | (1,965,684) |
Non-cash changes,Foreign exchange |  | 0 |  | 0 |  | 41,560 |
Non-cash changes,Others | [1] | 0 |  | 0 |  | 0 |
Ending Balance |  | 8,515,000 |  | 13,530,000 |  | 0 |
Long-term loans (current portion included) [member] |  |  |  |  |  |  |
Disclosure of reconciliation of liabilities arising from financing activities [line items] |  |  |  |  |  |  |
Beginning balance |  | 22,883,344 |  | 19,279,342 |  | 36,624,907 |
Cash Flows |  | 13,178,434 |  | 3,857,704 |  | (18,816,259) |
Non-cash changes,Foreign exchange |  | 415,131 |  | (253,702) |  | 1,470,694 |
Non-cash changes,Others | [1] | 0 |  | 0 |  | 0 |
Ending Balance |  | 36,476,909 |  | 22,883,344 |  | 19,279,342 |
Bonds payable (current portion included) [member] |  |  |  |  |  |  |
Disclosure of reconciliation of liabilities arising from financing activities [line items] |  |  |  |  |  |  |
Beginning balance |  | 38,359,352 |  | 28,184,687 |  | 40,536,658 |
Cash Flows |  | (8,500,465) |  | 9,989,245 |  | (13,305,050) |
Non-cash changes,Foreign exchange |  | 0 |  |  |  | 0 |
Non-cash changes,Others | [1] | 192,681 |  | 185,420 |  | 953,079 |
Ending Balance |  | 30,051,568 |  | 38,359,352 |  | 28,184,687 |
Guarantee deposits (current portion included) [member] |  |  |  |  |  |  |
Disclosure of reconciliation of liabilities arising from financing activities [line items] |  |  |  |  |  |  |
Beginning balance |  | 41,599,386 | [2] | 30,757,001 | [2] | 14,369,769 |
Cash Flows |  | (572,321) |  | 10,423,345 |  | 14,984,941 |
Non-cash changes,Foreign exchange |  | 1,847,429 |  | 419,040 |  | 1,402,291 |
Non-cash changes,Others | [1] | 0 |  | 0 |  |  |
Ending Balance |  | 42,874,494 |  | 41,599,386 | [2] | 30,757,001 | [2]
Lease liabilities [member] |  |  |  |  |  |  |
Disclosure of reconciliation of liabilities arising from financing activities [line items] |  |  |  |  |  |  |
Beginning balance |  | 5,393,187 |  | 5,737,095 |  | 5,068,754 |
Cash Flows |  | (731,138) |  | (666,439) |  | (712,854) |
Non-cash changes,Foreign exchange |  | 92,617 |  | (24,106) |  | 153,406 |
Non-cash changes,Others | [1] | 1,664,350 | [3] | 346,637 |  | 1,227,789 | [3]
Ending Balance |  | 6,419,016 |  | 5,393,187 |  | 5,737,095 |
Other financial liabilities [member] |  |  |  |  |  |  |
Disclosure of reconciliation of liabilities arising from financing activities [line items] |  |  |  |  |  |  |
Beginning balance |  | $ 0 |  | 21,449,487 |  | 20,966,209 |
Cash Flows |  |  |  | (21,209,443) |  | 0 |
Non-cash changes,Foreign exchange |  |  |  | (330,783) |  | 306,902 |
Non-cash changes,Others | [1] |  |  | 90,739 |  | 176,376 |
Ending Balance |  |  |  | $ 0 |  | $ 21,449,487 |
[1] | Other non-cash changes mainly consisted of discount amortization measured by the effective interest method.
[2] | Guarantee deposits mainly consisted of deposits of capacity reservation.
[3] | Mainly due to the addition to lease properties.

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