XML 103 R91.htm IDEA: XBRL DOCUMENT
v3.21.1

Significant Accounting Policies - Additional Information (Detail) ₩ in Millions | 12 Months Ended |  |
--- | --- | --- | ---
Dec. 31, 2020 KRW (₩) | Dec. 31, 2020 SGD ($) | Dec. 31, 2020 USD ($) | Dec. 31, 2019 KRW (₩)
Disclosure of significant accounting policies [line items] |  |  |  |
Borrowing | ₩ 7,316,298 | $ 284,000,000 | $ 519,598,989 | ₩ 7,298,867
Notional amount |  | $ 284,000,000 | $ 519,598,989 |
Derecognition of financial liabilities, percent | 10.00% |  |  |
Bottom of range [member] |  |  |  |
Disclosure of significant accounting policies [line items] |  |  |  |
Useful lives of investment property, excluding land depreciated cost model | 10 years |  |  |
Top of range [member] |  |  |  |
Disclosure of significant accounting policies [line items] |  |  |  |
Useful lives of investment property, excluding land depreciated cost model | 40 years |  |  |

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 The nominal or face amount of a financial instrument, used to calculate payments made on that instrument. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Name IAS -Number 1 -IssueDate 2020-01-01 -Paragraph 112 -Subparagraph c -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_112_c&doctype=Standard -URIDate 2020-01-01 + Details
Name: | ifrs-full_NotionalAmount
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | na
Period Type: | instant

X
- Definition The useful life, measured as period of time, used for investment property. [Refer: Investment property] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 40 -IssueDate 2020-01-01 -Paragraph 79 -Subparagraph b -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=40&code=ifrs-tx-2020-en-r&anchor=para_79_b&doctype=Standard -URIDate 2020-01-01 + Details
Name: | ifrs-full_UsefulLifeMeasuredAsPeriodOfTimeInvestmentPropertyCostModel
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage of fees related to te derecognition of financial liabilities. + References No definition available. + Details
Name: | kt_DerecognitionOfFinancialLiabilitiesPercent
Namespace Prefix: | kt_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Disclosure of significant accounting policies [line items] + References No definition available. + Details
Name: | kt_DisclosureOfSignificantAccountingPoliciesLineItems
Namespace Prefix: | kt_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | ifrs-full_RangeAxis=ifrs-full_BottomOfRangeMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_RangeAxis=ifrs-full_TopOfRangeMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |