XML 226 R211.htm IDEA: XBRL DOCUMENT v3.19.1

Fair Value Information - Schedule of Percentage Decrease in Discount for Lack of Marketability or Noncontrolling Interests Discount (Detail)	12 Months Ended
	Dec. 31, 2018
Bottom of Range [Member]
Disclosure of fair value measurement of assets and liabilities [Line Items]
Discount for lack of marketability	12.73%
Noncontrolling interests discount	24.41%
Top of Range [Member]
Disclosure of fair value measurement of assets and liabilities [Line Items]
Discount for lack of marketability	20.00%
Noncontrolling interests discount	25.00%

X

- Definition

Disclosure of fair value measurement of assets and liabilities.

+ References

No definition available.

+ Details

Name:	cht_DisclosureOfFairValueMeasurementOfAssetsAndLiabilitiesLineItems
Namespace Prefix:	cht_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Discount rate of noncontrolling interests.

+ References

No definition available.

+ Details

Name:	cht_DiscountRateOfNoncontrollingInterests
Namespace Prefix:	cht_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Percentage of discount for lack of marketability.

+ References

No definition available.

+ Details

Name:	cht_PercentageOfDiscountForLackOfMarketability
Namespace Prefix:	cht_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

X

- Details

Name:	ifrs-full_RangeAxis=ifrs-full_BottomOfRangeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	ifrs-full_RangeAxis=ifrs-full_TopOfRangeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: