XML 208 R194.htm IDEA: XBRL DOCUMENT v3.8.0.1

Financial Instruments - Liquidity Analysis for Derivative Financial Instruments (Detail) - TWD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Disclosure of maturity analysis for derivative financial liabilities [Line Items]
Undiscounted gross inflows (outflows) on derivatives	$ (2)	$ (2)
Forward exchange contracts inflows [Member]
Disclosure of maturity analysis for derivative financial liabilities [Line Items]
Undiscounted gross inflows (outflows) on derivatives	334	322
Forward exchange contracts outflows [Member]
Disclosure of maturity analysis for derivative financial liabilities [Line Items]
Undiscounted gross inflows (outflows) on derivatives	336	324
Less Than 1 Month [Member]
Disclosure of maturity analysis for derivative financial liabilities [Line Items]
Undiscounted gross inflows (outflows) on derivatives	(1)	0
Less Than 1 Month [Member] | Forward exchange contracts inflows [Member]
Disclosure of maturity analysis for derivative financial liabilities [Line Items]
Undiscounted gross inflows (outflows) on derivatives	125	55
Less Than 1 Month [Member] | Forward exchange contracts outflows [Member]
Disclosure of maturity analysis for derivative financial liabilities [Line Items]
Undiscounted gross inflows (outflows) on derivatives	126	55
1-3 Months [Member]
Disclosure of maturity analysis for derivative financial liabilities [Line Items]
Undiscounted gross inflows (outflows) on derivatives	(1)	(2)
1-3 Months [Member] | Forward exchange contracts inflows [Member]
Disclosure of maturity analysis for derivative financial liabilities [Line Items]
Undiscounted gross inflows (outflows) on derivatives	173	267
1-3 Months [Member] | Forward exchange contracts outflows [Member]
Disclosure of maturity analysis for derivative financial liabilities [Line Items]
Undiscounted gross inflows (outflows) on derivatives	174	269
3 Months to 1 Year [Member] | Forward exchange contracts inflows [Member]
Disclosure of maturity analysis for derivative financial liabilities [Line Items]
Undiscounted gross inflows (outflows) on derivatives	36	0
3 Months to 1 Year [Member] | Forward exchange contracts outflows [Member]
Disclosure of maturity analysis for derivative financial liabilities [Line Items]
Undiscounted gross inflows (outflows) on derivatives	$ 36	$ 0

X

- Definition

Derivative financial assets liabilities undiscounted cash flows.

+ References

No definition available.

+ Details

Name:	cht_DerivativeFinancialAssetsLiabilitiesUndiscountedCashFlows
Namespace Prefix:	cht_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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_DisclosureOfMaturityAnalysisForDerivativeFinancialLiabilitiesLineItems
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Details

Name:	ifrs-full_ClassesOfFinancialAssetsAxis=cht_ForwardExchangeContractsInflowsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	ifrs-full_ClassesOfFinancialAssetsAxis=cht_ForwardExchangeContractsOutflowsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	ifrs-full_MaturityAxis=ifrs-full_NotLaterThanOneMonthMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	ifrs-full_MaturityAxis=ifrs-full_LaterThanOneMonthAndNotLaterThanThreeMonthsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	ifrs-full_MaturityAxis=ifrs-full_LaterThanThreeMonthsAndNotLaterThanOneYearMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: