XML 117 R105.htm IDEA: XBRL DOCUMENT v3.21.1

Other Financial Assets and Liabilities - Additional Information (Detail) - KRW (₩) ₩ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Disclosure of detailed information about financial instruments [line items]
Ineffective portion recognized in profit or loss cash flow hedge valuation gain	₩ 2,711	₩ 4,181	₩ 263
Reclassified as accumulated other comprehensive income after tax	265,087
Retained earnings of attributable to owners	12,155,420	11,590,916
Disposal of investments in associates and joint ventures	24	₩ 16,930	₩ 7,832
Equity Instruments Listed [member]
Disclosure of detailed information about financial instruments [line items]
Retained earnings of attributable to owners	184,330
Disposal of investments in associates and joint ventures	₩ 350,777

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

X

- Definition

The gains (losses) on the ineffective portion of cash flow hedges recognised in profit or loss. [Refer: Cash flow hedges [member]]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Note Expiry date 2021-01-01
-Name IFRS
-Number 7
-IssueDate 2020-01-01
-Paragraph 24
-Subparagraph b
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2017-en-b&anchor=para_24_b&doctype=Standard&book=b
-URIDate 2020-01-01

+ Details

Name:	ifrs-full_GainsLossesOnIneffectivenessOfCashFlowHedgesRecognisedInProfitOrLoss
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

X

- Definition

The amount of other comprehensive income that will be reclassified to profit or loss, net of tax. [Refer: Other comprehensive income]

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Name IAS
-Number 1
-IssueDate 2020-01-01
-Paragraph IG6
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_IG6&doctype=Implementation%20Guidance
-URIDate 2020-01-01

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Name IAS
-Number 1
-IssueDate 2020-01-01
-Paragraph 82A
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_82A&doctype=Standard
-URIDate 2020-01-01

+ Details

Name:	ifrs-full_OtherComprehensiveIncomeThatWillBeReclassifiedToProfitOrLossNetOfTax
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

X

- Definition

The cash inflow from sales of investments accounted for using the equity method. [Refer: Investments accounted for using equity method]

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 7
-IssueDate 2020-01-01
-Paragraph 16
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=7&code=ifrs-tx-2020-en-r&anchor=para_16&doctype=Standard
-URIDate 2020-01-01

+ Details

Name:	ifrs-full_ProceedsFromSalesOfInvestmentsAccountedForUsingEquityMethod
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

X

- Definition

A component of equity representing the entity's cumulative undistributed earnings or deficit.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Name IAS
-Number 1
-IssueDate 2020-01-01
-Paragraph 78
-Subparagraph e
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_78_e&doctype=Standard
-URIDate 2020-01-01

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Name IAS
-Number 1
-IssueDate 2020-01-01
-Paragraph IG6
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_IG6&doctype=Implementation%20Guidance
-URIDate 2020-01-01

+ Details

Name:	ifrs-full_RetainedEarnings
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

X

- Details

Name:	ifrs-full_ClassesOfAssetsAxis=kt_EquityInstrumentsListedMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: