Revenue from contract with customer line item.

No definition available.

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Namespace Prefix:	cht_
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Period Type:	duration

- Definition

The amount of amortisation for assets recognised from the costs incurred to obtain or fulfil contracts with customers. [Refer: Assets recognised from costs to obtain or fulfil contracts with customers; Amortisation expense]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 15
-IssueDate 2020-01-01
-Paragraph 128
-Subparagraph b
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=15&code=ifrs-tx-2020-en-r&anchor=para_128_b&doctype=Standard
-URIDate 2020-01-01

+ Details

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

- Definition

The explanation of when the entity expects to recognise the transaction price allocated to the remaining performance obligations as revenue. [Refer: Revenue from contracts with customers; Transaction price allocated to remaining performance obligations]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 15
-IssueDate 2020-01-01
-Paragraph 120
-Subparagraph b
-Clause ii
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=15&code=ifrs-tx-2020-en-r&anchor=para_120_b_ii&doctype=Standard
-URIDate 2020-01-01

+ Details

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

- Definition

The amount of the transaction price allocated to the performance obligations that are unsatisfied (or partially unsatisfied) as of the end of the reporting period. The transaction price is the amount of consideration to which an entity expects to be entitled in exchange for transferring promised goods or services to a customer, excluding amounts collected on behalf of third parties (for example, some sales taxes). [Refer: Performance obligations [member]]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 15
-IssueDate 2020-01-01
-Paragraph 120
-Subparagraph a
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=15&code=ifrs-tx-2020-en-r&anchor=para_120_a&doctype=Standard
-URIDate 2020-01-01

+ Details

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

- Details

Name:	ifrs-full_ProductsAndServicesAxis=cht_TelecommunicationsBusinessMember
Namespace Prefix:
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Balance Type:
Period Type:

- Details

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- Details

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- Details

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- Details

Name:	ifrs-full_ProductsAndServicesAxis=cht_ProjectBusinessMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Revenue - Additional Information (Detail) $ in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2020 TWD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2019 TWD ($)	Dec. 31, 2018 TWD ($)
Revenue From Contract With Customer Line Item
Amortization of incremental costs of obtaining contracts	$ 772	$ 27	$ 1,173	$ 1,941
Telecommunications Business [Member]
Revenue From Contract With Customer Line Item
Transaction price allocated to performance obligations	$ 29,501
Remaining performance obligations, timing of satisfaction	The Company expects to recognize such revenue of $18,729 million, $9,082 million and $1,690 million in 2021, 2022 and 2023, respectively.	The Company expects to recognize such revenue of $18,729 million, $9,082 million and $1,690 million in 2021, 2022 and 2023, respectively.
Telecommunications Business [Member] \| Year 1 [Member]
Revenue From Contract With Customer Line Item
Transaction price allocated to performance obligations	$ 18,729
Telecommunications Business [Member] \| Later than one year and not later than two years [member]
Revenue From Contract With Customer Line Item
Transaction price allocated to performance obligations	9,082
Telecommunications Business [Member] \| Later than two years and not later than three years [member]
Revenue From Contract With Customer Line Item
Transaction price allocated to performance obligations	1,690
Project Business [Member]
Revenue From Contract With Customer Line Item
Transaction price allocated to performance obligations	$ 18,555
Remaining performance obligations, timing of satisfaction	The Company recognizes revenues when the project business contract is completed and accepted by customers. The Company expects to recognize such revenue of $7,977 million, $5,897 million and $4,681 million in 2021, 2022 and 2023, respectively.	The Company recognizes revenues when the project business contract is completed and accepted by customers. The Company expects to recognize such revenue of $7,977 million, $5,897 million and $4,681 million in 2021, 2022 and 2023, respectively.
Project Business [Member] \| Year 1 [Member]
Revenue From Contract With Customer Line Item
Transaction price allocated to performance obligations	$ 7,977
Project Business [Member] \| Later than one year and not later than two years [member]
Revenue From Contract With Customer Line Item
Transaction price allocated to performance obligations	5,897
Project Business [Member] \| Later than two years and not later than three years [member]
Revenue From Contract With Customer Line Item
Transaction price allocated to performance obligations	$ 4,681