XML 133 R118.htm IDEA: XBRL DOCUMENT v3.19.1

Subsidiaries - Additional Information (Detail)	Dec. 31, 2018	Dec. 31, 2017
CHIEF Telecom Inc. (CHIEF) [Member]
Disclosure of subsidiaries [Line Items]
Equity ownership percentage	57.00%	67.00%
Chunghwa Investment Co., Ltd. (CHI) [Member] | Chunghwa Precision Test Tech. Co., Ltd. (CHPT) [Member]
Disclosure of subsidiaries [Line Items]
Equity ownership percentage	34.25%
Chunghwa Telecom Co., Ltd. and Chunghwa Investment Co., Ltd. (CHI) [Member] | CHIEF Telecom Inc. (CHIEF) [Member]
Disclosure of subsidiaries [Line Items]
Equity ownership percentage	60.23%
Chunghwa Telecom Co., Ltd. and Chunghwa Investment Co., Ltd. (CHI) [Member] | Senao International Co., Ltd. (SENAO) [Member]
Disclosure of subsidiaries [Line Items]
Equity ownership percentage	28.18%	28.93%
Senao International Co., Ltd. (SENAO) [Member] | Youth Co., Ltd. (Youth) [Member]
Disclosure of subsidiaries [Line Items]
Equity ownership percentage	93.00%	89.00%

X

- Definition

Percentage of ownership interest in subsidiary.

+ References

No definition available.

+ Details

Name:	cht_PercentageOfOwnershipInterestInSubsidiary
Namespace Prefix:	cht_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

X

- Definition

Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes of the table.

+ References

No definition available.

+ Details

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

X

- Details

Name:	ifrs-full_SignificantInvestmentsInSubsidiariesAxis=cht_CHIEFTelecomIncMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	ifrs-full_CategoriesOfRelatedPartiesAxis=cht_ChunghwaInvestmentCoLtdMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	ifrs-full_SignificantInvestmentsInSubsidiariesAxis=cht_ChunghwaPrecisionTestTechCoLtdMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	ifrs-full_CategoriesOfRelatedPartiesAxis=cht_ChunghwaTelecomCoLtdAndChunghwaInvestmentCoLtdMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	ifrs-full_SignificantInvestmentsInSubsidiariesAxis=cht_SenaoInternationalCoLtdMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	ifrs-full_CategoriesOfRelatedPartiesAxis=cht_SenaoInternationalCoLtdMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	ifrs-full_SignificantInvestmentsInSubsidiariesAxis=cht_YouthCoLtdMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: