XML 154 R142.htm IDEA: XBRL DOCUMENT
v3.19.1

Borrowings - Summary of Long-term Borrowings (Parenthetical) (Detail) - ₩ / shares | 12 Months Ended |
--- | --- | ---
Dec. 31, 2018 | Dec. 31, 2010
Inter-Korean Cooperation Fund [member] |  |
Disclosure of detailed information about borrowings [line items] |  |
Long term debt repayment | The above Inter-Korean Cooperation Fund is repayable in installments over 13 years after a seven-year grace period. |
Vessel facility loans [member] | Shinhan Bank [member] |  |
Disclosure of detailed information about borrowings [line items] |  |
LIBOR rate | 2.808% |
Vessel facility loans [member] | Kookmin Bank [member] |  |
Disclosure of detailed information about borrowings [line items] |  |
LIBOR rate | 2.808% |
Redeemable convertible preferred stock [member] |  |
Disclosure of detailed information about borrowings [line items] |  |
Shares issued |  | 1,900,000
Par value per share |  | ₩ 500

X
- Definition The adjustment to the basis (reference rate) used for calculation of the interest rate on borrowings. [Refer: Borrowings] + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Name IFRS -Number 7 -IssueDate 2018-01-01 -Paragraph 7 -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=7&date=2018-03-01&anchor=para_7&doctype=Standard -URIDate 2018-03-16 + Details
Name: | ifrs-full_BorrowingsAdjustmentToInterestRateBasis
Namespace Prefix: | ifrs-full_
Data Type: | num:percentItemType
Balance Type: | na
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_DisclosureOfDetailedInformationAboutBorrowingsLineItems
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The number of shares issued by the entity. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Name IAS -Number 1 -IssueDate 2018-01-01 -Paragraph 106 -Subparagraph d -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=1&date=2018-03-01&anchor=para_106_d&doctype=Standard -URIDate 2018-03-16 + Details
Name: | ifrs-full_NumberOfSharesIssued
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- Definition The nominal value per share. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 1 -IssueDate 2018-01-01 -Paragraph 79 -Subparagraph a -Clause iii -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=1&date=2018-03-01&anchor=para_79_a_iii&doctype=Standard -URIDate 2018-03-16 + Details
Name: | ifrs-full_ParValuePerShare
Namespace Prefix: | ifrs-full_
Data Type: | num:perShareItemType
Balance Type: | na
Period Type: | instant

X
- Definition Long term debt repayment description. + References No definition available. + Details
Name: | kt_LongTermDebtRepaymentDescription
Namespace Prefix: | kt_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

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

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

X
- Details
Name: | ifrs-full_CounterpartiesAxis=kt_ShinhanBankMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_CounterpartiesAxis=kt_KookminBankMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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