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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
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

Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with members defined in one or many axes of the table.

+ References

No definition available.

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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

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