XML 166 R150.htm IDEA: XBRL DOCUMENT
v3.21.1

Short-term Bills Payable - Summary of Short-term Bills Payable (Detail) $ in Millions | Dec. 31, 2020 TWD ($) | Dec. 31, 2020 USD ($) | Dec. 31, 2019 TWD ($)
--- | --- | --- | ---
Short Term Bills Payable [Abstract] |  |  |
Commercial paper payable | $ 7,000,000,000 |  | $ 0
Less: Discounts on commercial paper payable | (1,000,000) |  | 0
Short-term bills payable | $ 6,999,000,000 | $ 249 | $ 0

X
- Definition Discounts on commercial paper payable. + References No definition available. + Details
Name: | cht_DiscountsOnCommercialPaperPayable
Namespace Prefix: | cht_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Short term bills payable. + References No definition available. + Details
Name: | cht_ShortTermBillsPayable
Namespace Prefix: | cht_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Short-term bills payable. + References No definition available. + Details
Name: | cht_ShortTermBillsPayableAbstract
Namespace Prefix: | cht_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The amount of commercial paper issued by the entity. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Name IAS -Number 1 -IssueDate 2020-01-01 -Paragraph 112 -Subparagraph c -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_112_c&doctype=Standard -URIDate 2020-01-01 + Details
Name: | ifrs-full_CommercialPapersIssued
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant