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Financial Instruments - Additional Information (Detail) - TWD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Disclosure of detailed information about financial instruments [Line Items]
Sensitivity rate	5.00%	5.00%	5.00%
Foreign currency risk [Member]
Disclosure of detailed information about financial instruments [Line Items]
Sensitivity rate	5.00%	5.00%	5.00%
Interest rate risk [member]
Disclosure of detailed information about financial instruments [Line Items]
Sensitivity rate	0.25%	0.25%	0.25%
Increase decrease in pre-tax income due to sensitivity analysis	$ 28	$ 17	$ 18
Equity price risk [Member]
Disclosure of detailed information about financial instruments [Line Items]
Sensitivity rate	5.00%	5.00%	5.00%
Equity price risk [Member] | Pre-tax profit [Member]
Disclosure of detailed information about financial instruments [Line Items]
Increase decrease in pretax income of financial assets at FVTPL, FVOCI	$ 48	$ 51	$ 50
Equity price risk [Member] | Pre-tax other comprehensive income [Member]
Disclosure of detailed information about financial instruments [Line Items]
Increase decrease in pretax income of financial assets at FVTPL, FVOCI	$ 233	$ 221	$ 175

X

- Definition

Increase decrease pre-tax profit and pre-tax other comprehensive income of financial assets at FVTOCI.

+ References

No definition available.

+ Details

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- Definition

Risk exposure associated with instruments sharing characteristic, percentage change in risk.

+ References

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+ Details

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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.

+ Details

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- Definition

The amount of risk exposure associated with financial instruments with a shared characteristic that identifies a concentration of risks. [Refer: Classes of financial instruments [domain]]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 7
-IssueDate 2024-01-01
-Paragraph B8
-Subparagraph c
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2024-en-r&anchor=para_B8_c&doctype=Appendix&subtype=B
-URIDate 2024-03-27

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