XML 158 R146.htm IDEA: XBRL DOCUMENT
v3.21.1

Borrowings - Summary of Repayment of Borrowings Including the Current Liabilities (Detail) ₩ in Millions | Dec. 31, 2020 KRW (₩) | Dec. 31, 2020 SGD ($) | Dec. 31, 2020 USD ($) | Dec. 31, 2019 KRW (₩)
--- | --- | --- | --- | ---
Disclosure of detailed information about borrowings [line items] |  |  |  |
Borrowings | ₩ 7,316,298 | $ 284,000,000 | $ 519,598,989 | ₩ 7,298,867
Debentures [member] |  |  |  |
Disclosure of detailed information about borrowings [line items] |  |  |  |
Borrowings | 5,714,340 |  |  | 5,972,554
Long-term borrowings [member] |  |  |  |
Disclosure of detailed information about borrowings [line items] |  |  |  |
Borrowings | 272,263 |  |  | 190,780
Gross carrying amount [member] |  |  |  |
Disclosure of detailed information about borrowings [line items] |  |  |  |
Borrowings | 7,338,522 |  |  |
Gross carrying amount [member] | Debentures [member] |  |  |  |
Disclosure of detailed information about borrowings [line items] |  |  |  |
Borrowings | 6,962,470 |  |  | ₩ 7,045,366
Gross carrying amount [member] | Debentures [member] | In local currency [member] |  |  |  |
Disclosure of detailed information about borrowings [line items] |  |  |  |
Borrowings | 4,348,000 |  |  |
Gross carrying amount [member] | Debentures [member] | In foreign currency [member] |  |  |  |
Disclosure of detailed information about borrowings [line items] |  |  |  |
Borrowings | 2,622,470 |  |  |
Gross carrying amount [member] | Long-term borrowings [member] |  |  |  |
Disclosure of detailed information about borrowings [line items] |  |  |  |
Borrowings | 368,052 |  |  |
Gross carrying amount [member] | Long-term borrowings [member] | In local currency [member] |  |  |  |
Disclosure of detailed information about borrowings [line items] |  |  |  |
Borrowings | 249,804 |  |  |
Gross carrying amount [member] | Long-term borrowings [member] | In foreign currency [member] |  |  |  |
Disclosure of detailed information about borrowings [line items] |  |  |  |
Borrowings | 118,248 |  |  |
Gross carrying amount [member] | Jan 1, 2020 - Dec 31, 2020 [member] |  |  |  |
Disclosure of detailed information about borrowings [line items] |  |  |  |
Borrowings | 1,418,513 |  |  |
Gross carrying amount [member] | Jan 1, 2020 - Dec 31, 2020 [member] | Debentures [member] |  |  |  |
Disclosure of detailed information about borrowings [line items] |  |  |  |
Borrowings | 1,228,682 |  |  |
Gross carrying amount [member] | Jan 1, 2020 - Dec 31, 2020 [member] | Debentures [member] | In local currency [member] |  |  |  |
Disclosure of detailed information about borrowings [line items] |  |  |  |
Borrowings | 1,060,000 |  |  |
Gross carrying amount [member] | Jan 1, 2020 - Dec 31, 2020 [member] | Debentures [member] | In foreign currency [member] |  |  |  |
Disclosure of detailed information about borrowings [line items] |  |  |  |
Borrowings | 168,682 |  |  |
Gross carrying amount [member] | Jan 1, 2020 - Dec 31, 2020 [member] | Long-term borrowings [member] |  |  |  |
Disclosure of detailed information about borrowings [line items] |  |  |  |
Borrowings | 189,831 |  |  |
Gross carrying amount [member] | Jan 1, 2020 - Dec 31, 2020 [member] | Long-term borrowings [member] | In local currency [member] |  |  |  |
Disclosure of detailed information about borrowings [line items] |  |  |  |
Borrowings | 147,307 |  |  |
Gross carrying amount [member] | Jan 1, 2020 - Dec 31, 2020 [member] | Long-term borrowings [member] | In foreign currency [member] |  |  |  |
Disclosure of detailed information about borrowings [line items] |  |  |  |
Borrowings | 42,524 |  |  |
Gross carrying amount [member] | Jan 1, 2021 - Dec 31, 2021 [member] |  |  |  |
Disclosure of detailed information about borrowings [line items] |  |  |  |
Borrowings | 1,346,609 |  |  |
Gross carrying amount [member] | Jan 1, 2021 - Dec 31, 2021 [member] | Debentures [member] |  |  |  |
Disclosure of detailed information about borrowings [line items] |  |  |  |
Borrowings | 1,307,261 |  |  |
Gross carrying amount [member] | Jan 1, 2021 - Dec 31, 2021 [member] | Debentures [member] | In local currency [member] |  |  |  |
Disclosure of detailed information about borrowings [line items] |  |  |  |
Borrowings | 560,000 |  |  |
Gross carrying amount [member] | Jan 1, 2021 - Dec 31, 2021 [member] | Debentures [member] | In foreign currency [member] |  |  |  |
Disclosure of detailed information about borrowings [line items] |  |  |  |
Borrowings | 747,261 |  |  |
Gross carrying amount [member] | Jan 1, 2021 - Dec 31, 2021 [member] | Long-term borrowings [member] |  |  |  |
Disclosure of detailed information about borrowings [line items] |  |  |  |
Borrowings | 39,348 |  |  |
Gross carrying amount [member] | Jan 1, 2021 - Dec 31, 2021 [member] | Long-term borrowings [member] | In local currency [member] |  |  |  |
Disclosure of detailed information about borrowings [line items] |  |  |  |
Borrowings | 518 |  |  |
Gross carrying amount [member] | Jan 1, 2021 - Dec 31, 2021 [member] | Long-term borrowings [member] | In foreign currency [member] |  |  |  |
Disclosure of detailed information about borrowings [line items] |  |  |  |
Borrowings | 38,830 |  |  |
Gross carrying amount [member] | Jan 1, 2022 - Dec 31, 2022 [member] |  |  |  |
Disclosure of detailed information about borrowings [line items] |  |  |  |
Borrowings | 1,069,704 |  |  |
Gross carrying amount [member] | Jan 1, 2022 - Dec 31, 2022 [member] | Debentures [member] |  |  |  |
Disclosure of detailed information about borrowings [line items] |  |  |  |
Borrowings | 932,310 |  |  |
Gross carrying amount [member] | Jan 1, 2022 - Dec 31, 2022 [member] | Debentures [member] | In local currency [member] |  |  |  |
Disclosure of detailed information about borrowings [line items] |  |  |  |
Borrowings | 590,000 |  |  |
Gross carrying amount [member] | Jan 1, 2022 - Dec 31, 2022 [member] | Debentures [member] | In foreign currency [member] |  |  |  |
Disclosure of detailed information about borrowings [line items] |  |  |  |
Borrowings | 342,310 |  |  |
Gross carrying amount [member] | Jan 1, 2022 - Dec 31, 2022 [member] | Long-term borrowings [member] |  |  |  |
Disclosure of detailed information about borrowings [line items] |  |  |  |
Borrowings | 137,394 |  |  |
Gross carrying amount [member] | Jan 1, 2022 - Dec 31, 2022 [member] | Long-term borrowings [member] | In local currency [member] |  |  |  |
Disclosure of detailed information about borrowings [line items] |  |  |  |
Borrowings | 100,500 |  |  |
Gross carrying amount [member] | Jan 1, 2022 - Dec 31, 2022 [member] | Long-term borrowings [member] | In foreign currency [member] |  |  |  |
Disclosure of detailed information about borrowings [line items] |  |  |  |
Borrowings | 36,894 |  |  |
Gross carrying amount [member] | Jan 1, 2023 - Dec 31, 2023 [member] |  |  |  |
Disclosure of detailed information about borrowings [line items] |  |  |  |
Borrowings | 845,510 |  |  |
Gross carrying amount [member] | Jan 1, 2023 - Dec 31, 2023 [member] | Debentures [member] |  |  |  |
Disclosure of detailed information about borrowings [line items] |  |  |  |
Borrowings | 845,017 |  |  |
Gross carrying amount [member] | Jan 1, 2023 - Dec 31, 2023 [member] | Debentures [member] | In local currency [member] |  |  |  |
Disclosure of detailed information about borrowings [line items] |  |  |  |
Borrowings | 460,000 |  |  |
Gross carrying amount [member] | Jan 1, 2023 - Dec 31, 2023 [member] | Debentures [member] | In foreign currency [member] |  |  |  |
Disclosure of detailed information about borrowings [line items] |  |  |  |
Borrowings | 385,017 |  |  |
Gross carrying amount [member] | Jan 1, 2023 - Dec 31, 2023 [member] | Long-term borrowings [member] |  |  |  |
Disclosure of detailed information about borrowings [line items] |  |  |  |
Borrowings | 493 |  |  |
Gross carrying amount [member] | Jan 1, 2023 - Dec 31, 2023 [member] | Long-term borrowings [member] | In local currency [member] |  |  |  |
Disclosure of detailed information about borrowings [line items] |  |  |  |
Borrowings | 493 |  |  |
Gross carrying amount [member] | After 2024 [member] |  |  |  |
Disclosure of detailed information about borrowings [line items] |  |  |  |
Borrowings | 2,658,186 |  |  |
Gross carrying amount [member] | After 2024 [member] | Debentures [member] |  |  |  |
Disclosure of detailed information about borrowings [line items] |  |  |  |
Borrowings | 2,657,200 |  |  |
Gross carrying amount [member] | After 2024 [member] | Debentures [member] | In local currency [member] |  |  |  |
Disclosure of detailed information about borrowings [line items] |  |  |  |
Borrowings | 1,678,000 |  |  |
Gross carrying amount [member] | After 2024 [member] | Debentures [member] | In foreign currency [member] |  |  |  |
Disclosure of detailed information about borrowings [line items] |  |  |  |
Borrowings | 979,200 |  |  |
Gross carrying amount [member] | After 2024 [member] | Long-term borrowings [member] |  |  |  |
Disclosure of detailed information about borrowings [line items] |  |  |  |
Borrowings | 986 |  |  |
Gross carrying amount [member] | After 2024 [member] | Long-term borrowings [member] | In local currency [member] |  |  |  |
Disclosure of detailed information about borrowings [line items] |  |  |  |
Borrowings | ₩ 986 |  |  |

X
- Definition The amount of outstanding funds that the entity is obligated to repay. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Name IAS -Number 1 -IssueDate 2020-01-01 -Paragraph 55 -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_55&doctype=Standard -URIDate 2020-01-01 + Details
Name: | ifrs-full_Borrowings
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
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
- Details
Name: | ifrs-full_BorrowingsByNameAxis=kt_DebenturesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_BorrowingsByNameAxis=ifrs-full_LongtermBorrowingsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_CarryingAmountAccumulatedDepreciationAmortisationAndImpairmentAndGrossCarryingAmountAxis=ifrs-full_GrossCarryingAmountMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_CurrencyAxis=kt_LocalCurrenyMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_CurrencyAxis=kt_ForeignCurrencyMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_MaturityAxis=ifrs-full_LaterThanOneYearMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_MaturityAxis=ifrs-full_LaterThanOneYearAndNotLaterThanTwoYearsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_MaturityAxis=ifrs-full_LaterThanTwoYearsAndNotLaterThanThreeYearsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_MaturityAxis=ifrs-full_LaterThanThreeYearsAndNotLaterThanFourYearsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_MaturityAxis=ifrs-full_LaterThanFiveYearsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |