XML 148 R134.htm IDEA: XBRL DOCUMENT
v3.8.0.1

Long Term Loans - Summary of Long-term Loans (Detail) - Long-term loans [Member] - TWD ($) $ in Millions | Dec. 31, 2017 | Dec. 31, 2016
--- | --- | ---
Disclosure of detailed information about borrowings [Line Items] |  |
Secured loans | $ 1,600 | $ 1,600
Secured loans [Member] |  |
Disclosure of detailed information about borrowings [Line Items] |  |
Interest rates of loans | 0.91% | 0.91%

X
- Definition The interest rate on borrowings. [Refer: Borrowings] + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Name IFRS -Number 7 -IssueDate 2016-01-13 -Paragraph 7 -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=7&date=2016-03-30&anchor=para_7&doctype=Standard -URIDate 2016-03-31 + Details
Name: | ifrs-full_BorrowingsInterestRate
Namespace Prefix: | ifrs-full_
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_DisclosureOfDetailedInformationAboutBorrowingsLineItems
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The amount of loans received from banks that have been secured by collateral. [Refer: Loans received] + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Name IAS -Number 1 -IssueDate 2016-01-13 -Paragraph 112 -Subparagraph c -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=1&date=2016-03-30&anchor=para_112_c&doctype=Standard -URIDate 2016-03-31 + Details
Name: | ifrs-full_SecuredBankLoansReceived
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Details
Name: | ifrs-full_ClassesOfFinancialInstrumentsAxis=cht_LongTermLoansMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_BorrowingsByNameAxis=cht_SecuredLoansMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |