Provisions - Summary of Provisions (Detail) $ in Millions, $ in Millions	Dec. 31, 2023 TWD ($)	Dec. 31, 2023 USD ($)	Dec. 31, 2022 TWD ($)	Dec. 31, 2021 TWD ($)	Dec. 31, 2020 TWD ($)
Provisions [abstract]
Employee benefits	$ 387		$ 65
Warranties	238		235
Onerous contracts	194		95
Others	3		4
Provisions	822		399	$ 427	$ 415
Current	337	$ 11	226
Noncurrent	$ 485	$ 16	$ 173

Provisions for onerous contracts.

No definition available.

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Namespace Prefix:	cht_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The amount of current provisions, including provisions for employee benefits. [Refer: Provisions]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 1
-IssueDate 2023-01-01
-Paragraph 54
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-URIDate 2023-03-23

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The amount of miscellaneous other provisions. [Refer: Other provisions]

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 1
-IssueDate 2023-01-01
-Paragraph 78
-Subparagraph d
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2023-en-r&anchor=para_78_d&doctype=Standard
-URIDate 2023-03-23

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The amount of non-current provisions, including provisions for employee benefits. [Refer: Provisions]

+ References

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The amount of liabilities of uncertain timing or amount, including provisions for employee benefits.

+ References

+ Details

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Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- References

No definition available.

+ Details

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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The amount of provisions for employee benefits. [Refer: Employee benefits expense; Provisions]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 1
-IssueDate 2023-01-01
-Paragraph 78
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-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2023-en-r&anchor=para_78_d&doctype=Standard
-URIDate 2023-03-23

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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- Definition

The amount of provision for estimated costs of making good under warranties for products sold. [Refer: Provisions]

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Name IAS
-Number 37
-IssueDate 2023-01-01
-Section Example 1 Warranties
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=37&code=ifrs-tx-2023-en-r&doctype=Illustrative%20Examples&dita_xref=IAS37_IE_C_ex1_TI
-URIDate 2023-03-23

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-URIDate 2023-03-23

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant