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v3.21.1

Revenue from Contracts with Customers and Relevant Contract Assets and Liabilities - Additional Information (Detail) - KRW (₩) ₩ in Millions | 12 Months Ended
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Dec. 31, 2020 | Dec. 31, 2019
Disclosure of disaggregation of revenue from contracts with customers [abstract] |  |
Operating expenses | ₩ 1,831,638 | ₩ 1,681,039

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- References No definition available. + Details
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- Definition Operating expenses related to contract cost assets + References No definition available. + Details
Name: | kt_OperatingExpensesRelatedToContractCostAssets
Namespace Prefix: | kt_
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Balance Type: | debit
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