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Contents of Significant Accounts - Summary of Fair Value of Each Investment in Equity Instrument (Detail) - TWD ($) $ in Thousands | Dec. 31, 2024 | Dec. 31, 2023
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Disclosure of fair value of investments in equity instruments designated at fair value through other comprehensive income [line items] |  |
Fair value of investments in equity instruments | $ 5,893,000 | $ 5,753,000
UNIMICRON HOLDING LIMITED [member] |  |
Disclosure of fair value of investments in equity instruments designated at fair value through other comprehensive income [line items] |  |
Fair value of investments in equity instruments | 2,474,388 | 2,514,120
ITE TECH. INC. [member] |  |
Disclosure of fair value of investments in equity instruments designated at fair value through other comprehensive income [line items] |  |
Fair value of investments in equity instruments | 2,093,997 | 2,100,977
CHIPBOND TECHNOLOGY CORPORATION [member] |  |
Disclosure of fair value of investments in equity instruments designated at fair value through other comprehensive income [line items] |  |
Fair value of investments in equity instruments | 3,423,750 | 3,843,744
NOVATEK MICROELECTRONICS CORP. (NOVATEK) [member] |  |
Disclosure of fair value of investments in equity instruments designated at fair value through other comprehensive income [line items] |  |
Fair value of investments in equity instruments | 8,255,183 | 8,501,851
KAI-HONG ENERGY CO., LTD. [Member] |  |
Disclosure of fair value of investments in equity instruments designated at fair value through other comprehensive income [line items] |  |
Fair value of investments in equity instruments | 64,865 | 0
SHIN-ETSU HANDOTAI TAIWAN CO., LTD. [member] |  |
Disclosure of fair value of investments in equity instruments designated at fair value through other comprehensive income [line items] |  |
Fair value of investments in equity instruments | 692,265 | 548,205
MTIC HOLDINGS PTE. LTD. [member] |  |
Disclosure of fair value of investments in equity instruments designated at fair value through other comprehensive income [line items] |  |
Fair value of investments in equity instruments | $ 204,880 | $ 175,063

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- Definition The amount of investments in equity instruments that the entity has designated at fair value through other comprehensive income. [Refer: At fair value [member]; Other comprehensive income] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 7 -IssueDate 2024-01-01 -Paragraph 11A -Subparagraph c -URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2024-en-r&anchor=para_11A_c&doctype=Standard -URIDate 2024-03-27 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 7 -IssueDate 2024-01-01 -Paragraph 8 -Subparagraph h -URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2024-en-r&anchor=para_8_h&doctype=Standard -URIDate 2024-03-27 + Details
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