Extended useful life.

No definition available.

Name:	cht_ExtendedUsefulLife
Namespace Prefix:	cht_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Lease contract for a period.

+ References

No definition available.

+ Details

Name:	cht_LeaseContractForPeriod
Namespace Prefix:	cht_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Prepaid rent in related parties.

+ References

No definition available.

+ Details

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

- Definition

Right-of-use assets acquired.

+ References

No definition available.

+ Details

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

- 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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Namespace Prefix:	ifrs-full_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The amount of interest expense on lease liabilities. [Refer: Lease liabilities]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 16
-IssueDate 2024-01-01
-Paragraph 53
-Subparagraph b
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=16&code=ifrs-tx-2024-en-r&anchor=para_53_b&doctype=Standard
-URIDate 2024-03-27

+ Details

Name:	ifrs-full_InterestExpenseOnLeaseLiabilities
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The amount of interest income on deposits. [Refer: Interest income]

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 1
-IssueDate 2024-01-01
-Paragraph 112
-Subparagraph c
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2024-en-r&anchor=para_112_c&doctype=Standard
-URIDate 2024-03-27

+ Details

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

- Definition

The amount of liabilities related to the entity's leases. Lease is a contract, or part of a contract, that conveys the right to use an underlying asset for a period of time in exchange for consideration.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 16
-IssueDate 2024-01-01
-Paragraph 47
-Subparagraph b
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=16&code=ifrs-tx-2024-en-r&anchor=para_47_b&doctype=Standard
-URIDate 2024-03-27

+ Details

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

- Details

Name:	dei_LegalEntityAxis=cht_NextCommercialBankCoLtdMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_SignificantInvestmentsInAssociatesAxis=cht_ST2SatelliteVenturesPteLtdMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_CategoriesOfRelatedPartiesAxis=cht_St2SatelliteMember
Namespace Prefix:
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Related Parties Transactions - Additional Information (Detail) $ in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2024 TWD ($)	Dec. 31, 2023 TWD ($)	Dec. 31, 2022 TWD ($)	Dec. 31, 2024 SGD ($)
Disclosure of transactions between related parties [Line Items]
Lease contract value	$ 10,892	$ 10,975
Interest on lease liabilities	128	105	$ 75
Next Commercial Bank Co., Ltd. ("NCB") [Member]
Disclosure of transactions between related parties [Line Items]
Interest income on deposits	25	1
ST-2 Satellite Ventures Pte., Ltd. ("STS") [Member]
Disclosure of transactions between related parties [Line Items]
Lease contract value	1,667	1,800
Interest on lease liabilities	$ 7	$ 8	$ 8
ST2 Satellite [Member]
Disclosure of transactions between related parties [Line Items]
Lease term	15 years
Lease contract value	$ 6,000			$ 261
Lease contract value, prepayment amount	$ 3,068
Extended useful life	3 years 3 months
Right-of-use assets acquired	$ 1,125