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Contents of Significant Accounts - Post-Employment Benefits - Additional Information (Detail) - TWD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Disclosure of defined benefit plans and defined contribution plans [Line Items]
Actual returns on plan assets	$ 37	$ 136
Expected pension fund contribution in 2024	$ 700
Weighted-average durations of defined benefit obligation	6 years	7 years
Defined benefit plan [member]
Disclosure of defined benefit plans and defined contribution plans [Line Items]
Percentages of employees' total monthly salaries and wages to pension fund	2.00%	2.00%	2.00%
Pension expenses	$ 45	$ 34	$ 23
Defined contribution plan [member]
Disclosure of defined benefit plans and defined contribution plans [Line Items]
Percentage of employees' monthly salary or wages as monthly contributions to defined contribution plan	6.00%	6.00%	6.00%
Pension expenses	$ 1,655	$ 1,880	$ 1,636

X

- Definition

The estimate of the expected contributions to be made to a defined benefit plan for the next annual reporting period. [Refer: Defined benefit plans [member]]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 19
-IssueDate 2023-01-01
-Paragraph 147
-Subparagraph b
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=19&code=ifrs-tx-2023-en-r&anchor=para_147_b&doctype=Standard
-URIDate 2023-03-23

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 19
-IssueDate 2023-01-01
-Paragraph 148
-Subparagraph d
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- Definition

The amount of post-employment benefit expense included in profit or loss relating to defined benefit plans. [Refer: Profit (loss); Defined benefit plans [member]] [Contrast: Increase (decrease) in net defined benefit liability (asset) resulting from expense (income) in profit or loss]

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 19
-IssueDate 2023-01-01
-Paragraph 5
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=19&code=ifrs-tx-2023-en-r&anchor=para_5&doctype=Standard
-URIDate 2023-03-23

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 19
-IssueDate 2023-01-01
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-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=19&code=ifrs-tx-2023-en-r&anchor=para_135_b&doctype=Standard
-URIDate 2023-03-23

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- Definition

The amount of post-employment benefit expense relating to defined contribution plans. Defined contribution plans are post-employment benefit plans under which an entity pays fixed contributions into a separate entity (a fund) and will have no legal or constructive obligation to pay further contributions if the fund does not hold sufficient assets to pay all employee benefits relating to employee service in the current and prior periods.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 19
-IssueDate 2023-01-01
-Paragraph 53
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=19&code=ifrs-tx-2023-en-r&anchor=para_53&doctype=Standard
-URIDate 2023-03-23

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X

- Definition

The weighted average duration of a defined benefit obligation. [Refer: Weighted average [member]]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 19
-IssueDate 2023-01-01
-Paragraph 147
-Subparagraph c
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=19&code=ifrs-tx-2023-en-r&anchor=para_147_c&doctype=Standard
-URIDate 2023-03-23

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- Definition

Actual return on plan assets.

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- Definition

Disclosure of defined benefit plans and defined contribution plans [Line Items]

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- Definition

Percentage of employees' monthly salaries and wages as contributions to defined benefit plan.

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