XML 238 R226.htm IDEA: XBRL DOCUMENT
v3.21.1

Business Combination - Additional Information (Detail) - KRW (₩) ₩ in Millions | 12 Months Ended |
--- | --- | ---
Dec. 31, 2020 | Apr. 30, 2020
Disclosure of detailed information about business combination [Line Items] |  |
identifiable intangible assets generated | ₩ 410 |
Goodwill generated | 407 |
operating income of combined entity | 250,380 |
net loss of combined entity | 1,948 |
operating income | 387,697 |
net loss | 8,461 |
KT Engineering Co Ltd [Member] |  |
Disclosure of detailed information about business combination [Line Items] |  |
Number of shares acquired |  | 1,400,000
Percentage of ownership interest |  | 59.80%
KT Estate [Member] |  |
Disclosure of detailed information about business combination [Line Items] |  |
Number of shares acquired |  | 940,000
Percentage of ownership interest |  | 40.20%
Business combinations [member] |  |
Disclosure of detailed information about business combination [Line Items] |  |
identifiable intangible assets generated | 3 |
Goodwill generated | ₩ 407 |

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

X
- Definition The amount recognised as of the business combination's acquisition date for goodwill. [Refer: Goodwill; Business combinations [member]] + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Name IFRS -Number 3 -IssueDate 2020-01-01 -Paragraph B64 -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=3&code=ifrs-tx-2020-en-r&anchor=para_B64&doctype=Appendix&subtype=B -URIDate 2020-01-01 Reference 2: http://www.xbrl.org/2003/role/exampleRef -Name IFRS -Number 3 -IssueDate 2020-01-01 -Paragraph IE72 -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=3&code=ifrs-tx-2020-en-r&anchor=para_IE72&doctype=Illustrative%20Examples -URIDate 2020-01-01 + Details
Name: | ifrs-full_GoodwillRecognisedAsOfAcquisitionDate
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition The amount recognised as of the acquisition date for identifiable intangible assets acquired in a business combination. [Refer: Intangible assets other than goodwill; Business combinations [member]] + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Name IFRS -Number 3 -IssueDate 2020-01-01 -Paragraph B64 -Subparagraph i -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=3&code=ifrs-tx-2020-en-r&anchor=para_B64_i&doctype=Appendix&subtype=B -URIDate 2020-01-01 Reference 2: http://www.xbrl.org/2003/role/exampleRef -Name IFRS -Number 3 -IssueDate 2020-01-01 -Paragraph IE72 -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=3&code=ifrs-tx-2020-en-r&anchor=para_IE72&doctype=Illustrative%20Examples -URIDate 2020-01-01 + Details
Name: | ifrs-full_IdentifiableIntangibleAssetsRecognisedAsOfAcquisitionDate
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition The percentage of voting equity interests acquired in a business combination. [Refer: Business combinations [member]] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 3 -IssueDate 2020-01-01 -Paragraph B64 -Subparagraph c -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=3&code=ifrs-tx-2020-en-r&anchor=para_B64_c&doctype=Appendix&subtype=B -URIDate 2020-01-01 + Details
Name: | ifrs-full_PercentageOfVotingEquityInterestsAcquired
Namespace Prefix: | ifrs-full_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition The profit (loss) of the acquiree, since the acquisition date, included in the consolidated statement of comprehensive income. [Refer: Profit (loss)] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 3 -IssueDate 2020-01-01 -Paragraph B64 -Subparagraph q -Clause i -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=3&code=ifrs-tx-2020-en-r&anchor=para_B64_q_i&doctype=Appendix&subtype=B -URIDate 2020-01-01 + Details
Name: | ifrs-full_ProfitLossOfAcquiree
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The profit (loss) of the combined entity as though the acquisition date for all business combinations that occurred during the year had been as of the beginning of the annual reporting period. [Refer: Business combinations [member]; Profit (loss)] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 3 -IssueDate 2020-01-01 -Paragraph B64 -Subparagraph q -Clause ii -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=3&code=ifrs-tx-2020-en-r&anchor=para_B64_q_ii&doctype=Appendix&subtype=B -URIDate 2020-01-01 + Details
Name: | ifrs-full_ProfitLossOfCombinedEntity
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The amount of revenue of the acquiree since the acquisition date included in the consolidated statement of comprehensive income. [Refer: Revenue] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 3 -IssueDate 2020-01-01 -Paragraph B64 -Subparagraph q -Clause i -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=3&code=ifrs-tx-2020-en-r&anchor=para_B64_q_i&doctype=Appendix&subtype=B -URIDate 2020-01-01 + Details
Name: | ifrs-full_RevenueOfAcquiree
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The revenue of the combined entity as though the acquisition date for all business combinations that occurred during the year had been as of the beginning of the annual reporting period. [Refer: Business combinations [member]; Revenue] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 3 -IssueDate 2020-01-01 -Paragraph B64 -Subparagraph q -Clause ii -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=3&code=ifrs-tx-2020-en-r&anchor=para_B64_q_ii&doctype=Appendix&subtype=B -URIDate 2020-01-01 + Details
Name: | ifrs-full_RevenueOfCombinedEntity
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Number of shares acquired. + References No definition available. + Details
Name: | kt_NumberOfSharesAcquired
Namespace Prefix: | kt_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- Details
Name: | ifrs-full_BusinessCombinationsAxis=kt_KtEngineeringCoLtdMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_BusinessCombinationsAxis=kt_KtEstateMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_BusinessCombinationsAxis=ifrs-full_BusinessCombinationsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |