XML 135 R123.htm IDEA: XBRL DOCUMENT
v3.21.1

Investment Properties - Summary of Investment Properties Provided as Collateral (Detail) - Land and buildings [member] - KRW (₩) ₩ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2020 | Dec. 31, 2019
Deposits 1 [member] |  |
Disclosure of detailed information about investment property [line items] |  |
Carrying amount | ₩ 790,414 | ₩ 854,874
Secured amount | ₩ 62,968 | ₩ 62,896
Related account | Deposits | Deposits
Related amount | ₩ 56,247 | ₩ 56,831
Borrowings [member] |  |
Disclosure of detailed information about investment property [line items] |  |
Carrying amount | 2,861 | 1,915
Secured amount | ₩ 3,434 | ₩ 3,044
Related account | Borrowings | Borrowings
Related amount | ₩ 2,928 | ₩ 1,903

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

X
- Definition Deposits and borrowings + References No definition available. + Details
Name: | kt_DepositsAndBorrowings
Namespace Prefix: | kt_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Investment property, pledged as security + References No definition available. + Details
Name: | kt_InvestmentPropertyPledgedAsSecurity
Namespace Prefix: | kt_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Related amount description in investment property. + References No definition available. + Details
Name: | kt_RelatedAmountDescriptionInInvestmentProperty
Namespace Prefix: | kt_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Secured amount in investment property. + References No definition available. + Details
Name: | kt_SecuredAmountInInvestmentProperty
Namespace Prefix: | kt_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Details
Name: | ifrs-full_ClassesOfFinancialInstrumentsAxis=kt_Deposits1Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_TypesOfInvestmentPropertyAxis=ifrs-full_LandAndBuildingsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_ClassesOfFinancialInstrumentsAxis=kt_Borrowings1Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |