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Segment Information - Summary of Segment Information (Parenthetical) (Detail) ₩ in Millions | Dec. 31, 2020 KRW (₩)
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ICT [member] |
Disclosure of operating segments [line items] |
Property and equipment and intangible assets | ₩ 13,583,173

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

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- Definition Total Property and Equipment and Intangible assets. + References No definition available. + Details
Name: | kt_TotalPropertyAndEquipmentAndIntangibleAssets
Namespace Prefix: | kt_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

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- Details
Name: | ifrs-full_SegmentsAxis=kt_IctMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |