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

The amount of investments in subsidiaries, joint ventures and associates in an entity's separate financial statements. [Refer: Associates [member]; Joint ventures [member]; Subsidiaries [member]; Investments in subsidiaries reported in separate financial statements]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 27
-IssueDate 2022-03-24
-Paragraph 10
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=27&code=ifrs-tx-2022-en-r&anchor=para_10&doctype=Standard
-URIDate 2022-03-24

Name:	ifrs-full_InvestmentsInSubsidiariesJointVenturesAndAssociates
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

The entity's share of the profit (loss) from continuing operations of associates and joint ventures accounted for using the equity method. [Refer: Associates [member]; Continuing operations [member]; Investments accounted for using equity method; Joint ventures [member]; Profit (loss) from continuing operations]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 12
-IssueDate 2022-03-24
-Paragraph B16
-Subparagraph a
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=12&code=ifrs-tx-2022-en-r&anchor=para_B16_a&doctype=Appendix&subtype=B
-URIDate 2022-03-24

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

Acquisition (disposal) of investments in subsidiaries, joint ventures and associates.

No definition available.

Name:	kt_AcqusitionDisposalOfInvestmentsInSubsidiariesJointVenturesAndAssociates
Namespace Prefix:	kt_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

The increase (decrease) in Investments in Associates and Joint ventures resulting from other movements.

No definition available.

Name:	kt_IncreaseDecreaseThroughOtherMovementsInvestmentsInAssociatesAndJointVentures
Namespace Prefix:	kt_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Name:	ifrs-full_SignificantInvestmentsInAssociatesAxis=kt_HyundaiRoboticsCoLtdMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	ifrs-full_SignificantInvestmentsInAssociatesAxis=kt_KTIBKCFutureInvestmentFundMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	ifrs-full_SignificantInvestmentsInAssociatesAxis=kt_KBankInc.Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	ifrs-full_SignificantInvestmentsInAssociatesAxis=kt_KRealtyCrReitsNoOneMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	ifrs-full_SignificantInvestmentsInAssociatesAxis=kt_OthersMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	ifrs-full_SignificantInvestmentsInAssociatesAxis=kt_OtherAssociatesAndJointVenturesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	ifrs-full_SignificantInvestmentsInAssociatesAxis=kt_KifInvestmentFundMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	ifrs-full_SignificantInvestmentsInAssociatesAxis=kt_MegazoneCloudCorporationMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	ifrs-full_SignificantInvestmentsInAssociatesAxis=kt_IgisNo.4681GeneralPrivateRealEstateInvestmentCompanyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	ifrs-full_SignificantInvestmentsInAssociatesAxis=kt_KTDSCCreativeEconomyYouthStartUpInvestmentFundMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: