XML 184 R168.htm IDEA: XBRL DOCUMENT v3.21.1

Retirement Benefit Plans - Maturity Analysis of Undiscounted Benefit Payments (Detail) $ in Millions	12 Months Ended
	Dec. 31, 2020 TWD ($)
Disclosure Of Defined Benefit Plans [Abstract]
2021	$ 3,285
2022	7,056
2023	10,669
2024	11,799
2025 and thereafter	39,497
Total	$ 72,306

X

- Definition

Estimated future benefit payments.

+ References

No definition available.

+ Details

Name:	cht_EstimatedFutureBenefitPayments
Namespace Prefix:	cht_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

X

- Definition

Estimated future benefit payments five fiscal years thereafter.

+ References

No definition available.

+ Details

Name:	cht_EstimatedFutureBenefitPaymentsFiveFiscalYearsThereafter
Namespace Prefix:	cht_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

X

- Definition

Estimated future benefit payments next twelve months.

+ References

No definition available.

+ Details

Name:	cht_EstimatedFutureBenefitPaymentsNextTwelveMonths
Namespace Prefix:	cht_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

X

- Definition

Estimated future benefit payments year four.

+ References

No definition available.

+ Details

Name:	cht_EstimatedFutureBenefitPaymentsYearFour
Namespace Prefix:	cht_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

X

- Definition

Estimated future benefit payments year three.

+ References

No definition available.

+ Details

Name:	cht_EstimatedFutureBenefitPaymentsYearThree
Namespace Prefix:	cht_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

X

- Definition

Estimated future benefit payments year two.

+ References

No definition available.

+ Details

Name:	cht_EstimatedFutureBenefitPaymentsYearTwo
Namespace Prefix:	cht_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

X

- References

No definition available.

+ Details

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