XML 137 R123.htm IDEA: XBRL DOCUMENT
v3.8.0.1

Investment Properties - Estimated Service Lives of Investment Properties (Detail) | 12 Months Ended
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Dec. 31, 2017
Land improvements [Member] | Bottom of range [Member] |
Disclosure of detailed information about investment property [Line Items] |
Estimated service lives | P8Y
Land improvements [Member] | Top of range [Member] |
Disclosure of detailed information about investment property [Line Items] |
Estimated service lives | P30Y
Main buildings [Member] | Bottom of range [Member] |
Disclosure of detailed information about investment property [Line Items] |
Estimated service lives | P35Y
Main buildings [Member] | Top of range [Member] |
Disclosure of detailed information about investment property [Line Items] |
Estimated service lives | P60Y
Other building facilities [Member] | Bottom of range [Member] |
Disclosure of detailed information about investment property [Line Items] |
Estimated service lives | P4Y
Other building facilities [Member] | Top of range [Member] |
Disclosure of detailed information about investment property [Line Items] |
Estimated service lives | P10Y

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

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- Definition The useful lives or depreciation rates used for investment property. [Refer: Investment property] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 40 -IssueDate 2016-01-13 -Paragraph 79 -Subparagraph b -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=40&date=2016-03-30&anchor=para_79_b&doctype=Standard -URIDate 2016-03-31 + Details
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Namespace Prefix: | ifrs-full_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

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- Details
Name: | ifrs-full_ClassesOfPropertyPlantAndEquipmentAxis=cht_LandImprovements1Member
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Data Type: | na
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- Details
Name: | ifrs-full_RangeAxis=ifrs-full_BottomOfRangeMember
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Data Type: | na
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- Details
Name: | ifrs-full_RangeAxis=ifrs-full_TopOfRangeMember
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Data Type: | na
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- Details
Name: | ifrs-full_ClassesOfPropertyPlantAndEquipmentAxis=cht_MainBuildingsMember
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Data Type: | na
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- Details
Name: | ifrs-full_ClassesOfPropertyPlantAndEquipmentAxis=cht_OtherBuildingFacilitiesMember
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Data Type: | na
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