XML 162 R150.htm IDEA: XBRL DOCUMENT
v3.19.1

Net Defined Benefit Liabilities - Summary of Sensitivity of the Defined Benefit Obligations (Detail) ₩ in Millions | Dec. 31, 2018 KRW (₩)
--- | ---
Discount rate [member] |
Disclosure of sensitivity analysis for actuarial assumptions [Line items] |
Percentage changes in assumption | 0.50%
Effect on defined benefit obligation, increase in assumption | ₩ (72,851)
Effect on defined benefit obligation, decrease in assumption | ₩ 82,527
Salary growth rate [member] |
Disclosure of sensitivity analysis for actuarial assumptions [Line items] |
Percentage changes in assumption | 0.50%
Effect on defined benefit obligation, increase in assumption | ₩ 75,647
Effect on defined benefit obligation, decrease in assumption | ₩ (63,267)

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

X
- Definition The increase (decrease) in a defined benefit obligation that would have been caused by a decrease in a significant actuarial assumption that was reasonably possible at the end of the reporting period. [Refer: Actuarial assumptions [member]] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 19 -IssueDate 2018-01-01 -Paragraph 145 -Subparagraph a -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=19&date=2018-03-01&anchor=para_145_a&doctype=Standard -URIDate 2018-03-16 + Details
Name: | ifrs-full_IncreaseDecreaseInDefinedBenefitObligationDueToReasonablyPossibleDecreaseInActuarialAssumption
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The increase (decrease) in a defined benefit obligation that would have been caused by an increase in a significant actuarial assumption that was reasonably possible at the end of the reporting period. [Refer: Actuarial assumptions [member]] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 19 -IssueDate 2018-01-01 -Paragraph 145 -Subparagraph a -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=19&date=2018-03-01&anchor=para_145_a&doctype=Standard -URIDate 2018-03-16 + Details
Name: | ifrs-full_IncreaseDecreaseInDefinedBenefitObligationDueToReasonablyPossibleIncreaseInActuarialAssumption
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Percentage of reasonably possible increase decrease in actuarial assumption. + References No definition available. + Details
Name: | kt_PercentageOfReasonablyPossibleIncreaseDecreaseInActuarialAssumption
Namespace Prefix: | kt_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Details
Name: | ifrs-full_ActuarialAssumptionsAxis=ifrs-full_ActuarialAssumptionOfDiscountRatesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_ActuarialAssumptionsAxis=ifrs-full_ActuarialAssumptionOfExpectedRatesOfSalaryIncreasesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |