XML 209 R197.htm IDEA: XBRL DOCUMENT
v3.21.1

Cash Generated from Operations - Summary of Cash Flows from Operating Activities (Detail) - KRW (₩) ₩ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018
Cash flows from (used in) operating activities [abstract] |  |  |
Profit for the year | ₩ 746,256 | ₩ 695,868 | ₩ 719,412
Adjustments to reconcile net income |  |  |
Income tax expense | 285,349 | 320,060 | 314,565
Interest income | (291,425) | (303,722) | (265,817)
Interest expense | 265,035 | 278,975 | 296,894
Dividends income | (4,442) | (3,408) | (2,910)
Depreciation | 2,635,307 | 2,567,754 | 2,735,413
Amortization of intangible assets | 628,154 | 660,705 | 629,526
Depreciation of right-of-use assets | 404,175 | 442,629 |
Provision for severance benefits | 255,615 | 256,525 | 245,926
Impairment losses on trade receivables | 139,957 | 60,193 | 113,064
Share of net profit or loss of associates and joint ventures | (18,041) | 3,252 | 5,912
Loss(gain) on disposal of associates and joint ventures | 111 | 30 | (3,737)
Loss(gain) on disposal of right-of-use assets | 2,047 | 1,556 |
Impairment losses on assets held for sale |  | 7,586 |
Loss on disposal of property and equipment and investment in properties | 55,590 | 49,284 | 68,688
Loss(gain) on disposal of intangible assets | 246 | (1,248) | (4,256)
Loss on impairment of intangible assets | 211,636 | 61,899 | 12,997
Loss(gain) on foreign currency translation | (138,011) | 75,998 | 68,952
Loss(gain) on valuation and settlement of derivatives, net | 155,600 | (70,482) | (92,210)
Loss(gain) on disposal of financial assets at fair value through profit or loss | 329 | (5,115) | (1,712)
Gain on valuation of financial assets at fair value through profit or loss | (59,044) | (4,335) | (10,768)
Loss(gain) on disposal of financial assets at amortized cost | (138) | 43 | (44)
Others | 127,949 | 143,500 | (55,969)
Changes in operating assets and liabilities |  |  |
Decrease(increase) in trade receivables | 66,462 | (433,292) | (81,217)
Decrease(increase) in other receivables | 685,209 | (79,130) | 356,643
Decrease(increase) in other current assets | 9,089 | 984 | (123,258)
Decrease(increase) in other non-current assets | (86,039) | (178,180) | 19,556
Decrease(increase) in inventories | 288,507 | 240,488 | (480,543)
Increase(decrease) in trade payables | (135,760) | 44,354 | (167,841)
Decrease in other payables | (1,232,646) | (102,375) | (448,301)
Increase in other current liabilities | 127,076 | 43,384 | 291,548
Increase(decrease) in other non-current liabilities | (56,319) | (199,547) | 144,072
Decrease(Increase) in provisions | 2,264 | (12,164) | 85,946
Decrease(Increase) in deferred revenue | (1,948) | 641 | 48,201
Increase in plan assets | (136,336) | (375,499) | (53,301)
Payment of severance benefits | (186,520) | (119,716) | (153,209)
Cash generated from operations (1+2+3) | ₩ 4,745,293 | ₩ 4,058,065 | ₩ 4,212,222

X
- Definition Adjustments for decrease (increase) in inventories to reconcile profit (loss) to net cash flow from (used in) operating activities. [Refer: Inventories; Profit (loss)] + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Name IAS -Number 7 -IssueDate 2020-01-01 -Paragraph 20 -Subparagraph a -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=7&code=ifrs-tx-2020-en-r&anchor=para_20_a&doctype=Standard -URIDate 2020-01-01 + Details
Name: | ifrs-full_AdjustmentsForDecreaseIncreaseInInventories
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Adjustments for decrease (increase) in other current assets to reconcile profit (loss) to net cash flow from (used in) operating activities. [Refer: Other current assets; Profit (loss)] + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Name IAS -Number 7 -IssueDate 2020-01-01 -Paragraph 20 -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=7&code=ifrs-tx-2020-en-r&anchor=para_20&doctype=Standard -URIDate 2020-01-01 + Details
Name: | ifrs-full_AdjustmentsForDecreaseIncreaseInOtherCurrentAssets
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Adjustments for decrease (increase) in trade accounts receivable to reconcile profit (loss) to net cash flow from (used in) operating activities. [Refer: Profit (loss)] + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Name IAS -Number 7 -IssueDate 2020-01-01 -Paragraph 20 -Subparagraph a -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=7&code=ifrs-tx-2020-en-r&anchor=para_20_a&doctype=Standard -URIDate 2020-01-01 + Details
Name: | ifrs-full_AdjustmentsForDecreaseIncreaseInTradeAccountReceivable
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Adjustments for depreciation expense to reconcile profit (loss) to net cash flow from (used in) operating activities. [Refer: Profit (loss)] + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Name IAS -Number 7 -IssueDate 2020-01-01 -Paragraph 20 -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=7&code=ifrs-tx-2020-en-r&anchor=para_20&doctype=Standard -URIDate 2020-01-01 + Details
Name: | ifrs-full_AdjustmentsForDepreciationExpense
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Adjustments for dividend income to reconcile profit (loss) to net cash flow from (used in) operating activities. [Refer: Dividend income; Profit (loss)] + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Name IAS -Number 7 -IssueDate 2020-01-01 -Paragraph 20 -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=7&code=ifrs-tx-2020-en-r&anchor=para_20&doctype=Standard -URIDate 2020-01-01 + Details
Name: | ifrs-full_AdjustmentsForDividendIncome
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Adjustments for gain (loss) on disposals investments in subsidiaries, joint ventures and associates to reconcile profit (loss) to net cash flow from (used in) operating activities. [Refer: Associates [member]; Joint ventures [member]; Subsidiaries [member]; Investments in subsidiaries, joint ventures and associates; Profit (loss)] + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Name IAS -Number 7 -IssueDate 2020-01-01 -Paragraph 20 -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=7&code=ifrs-tx-2020-en-r&anchor=para_20&doctype=Standard -URIDate 2020-01-01 + Details
Name: | ifrs-full_AdjustmentsForGainLossOnDisposalOfInvestmentsInSubsidiariesJointVenturesAndAssociates
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Adjustments for gain (loss) on disposals of property, plant and equipment to reconcile profit (loss) to net cash flow from (used in) operating activities. [Refer: Profit (loss); Property, plant and equipment; Disposals, property, plant and equipment] + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Name IAS -Number 7 -IssueDate 2020-01-01 -Paragraph 20 -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=7&code=ifrs-tx-2020-en-r&anchor=para_20&doctype=Standard -URIDate 2020-01-01 + Details
Name: | ifrs-full_AdjustmentsForGainLossOnDisposalsPropertyPlantAndEquipment
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Adjustments for impairment loss (reversal of impairment loss) on trade and other receivables recognised in profit or loss to reconcile profit (loss) to net cash flow from (used in) operating activities. [Refer: Trade and other receivables; Impairment loss; Adjustments for impairment loss (reversal of impairment loss) recognised in profit or loss; Impairment loss (reversal of impairment loss) recognised in profit or loss] + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Name IAS -Number 7 -IssueDate 2020-01-01 -Paragraph 20 -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=7&code=ifrs-tx-2020-en-r&anchor=para_20&doctype=Standard -URIDate 2020-01-01 + Details
Name: | ifrs-full_AdjustmentsForImpairmentLossReversalOfImpairmentLossRecognisedInProfitOrLossTradeAndOtherReceivables
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Adjustments for income tax expense to reconcile profit (loss) to net cash flow from (used in) operating activities. [Refer: Profit (loss)] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 7 -IssueDate 2020-01-01 -Paragraph 35 -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=7&code=ifrs-tx-2020-en-r&anchor=para_35&doctype=Standard -URIDate 2020-01-01 + Details
Name: | ifrs-full_AdjustmentsForIncomeTaxExpense
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Adjustments for increase (decrease) in deferred income to reconcile profit (loss) to net cash flow from (used in) operating activities. [Refer: Deferred income; Profit (loss)] + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Name IAS -Number 7 -IssueDate 2020-01-01 -Paragraph 20 -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=7&code=ifrs-tx-2020-en-r&anchor=para_20&doctype=Standard -URIDate 2020-01-01 + Details
Name: | ifrs-full_AdjustmentsForIncreaseDecreaseInDeferredIncome
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Adjustments for increase (decrease) in other current liabilities to reconcile profit (loss) to net cash flow from (used in) operating activities. [Refer: Other current liabilities; Profit (loss)] + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Name IAS -Number 7 -IssueDate 2020-01-01 -Paragraph 20 -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=7&code=ifrs-tx-2020-en-r&anchor=para_20&doctype=Standard -URIDate 2020-01-01 + Details
Name: | ifrs-full_AdjustmentsForIncreaseDecreaseInOtherCurrentLiabilities
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Adjustments for increase (decrease) in trade accounts payable to reconcile profit (loss) to net cash flow from (used in) operating activities. [Refer: Profit (loss)] + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Name IAS -Number 7 -IssueDate 2020-01-01 -Paragraph 20 -Subparagraph a -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=7&code=ifrs-tx-2020-en-r&anchor=para_20_a&doctype=Standard -URIDate 2020-01-01 + Details
Name: | ifrs-full_AdjustmentsForIncreaseDecreaseInTradeAccountPayable
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Adjustments for interest expense to reconcile profit (loss) to net cash flow from (used in) operating activities. [Refer: Interest expense; Profit (loss)] + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Name IAS -Number 7 -IssueDate 2020-01-01 -Paragraph 20 -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=7&code=ifrs-tx-2020-en-r&anchor=para_20&doctype=Standard -URIDate 2020-01-01 + Details
Name: | ifrs-full_AdjustmentsForInterestExpense
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Adjustments for interest income expense to reconcile profit (loss) to net cash flow from (used in) operating activities. [Refer: Interest income; Profit (loss)] + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Name IAS -Number 7 -IssueDate 2020-01-01 -Paragraph 20 -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=7&code=ifrs-tx-2020-en-r&anchor=para_20&doctype=Standard -URIDate 2020-01-01 + Details
Name: | ifrs-full_AdjustmentsForInterestIncome
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- References No definition available. + Details
Name: | ifrs-full_AdjustmentsForReconcileProfitLossAbstract
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The amount of amortisation of intangible assets other than goodwill. [Refer: Depreciation and amortisation expense; Intangible assets other than goodwill] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 38 -IssueDate 2020-01-01 -Paragraph 118 -Subparagraph e -Clause vi -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=38&code=ifrs-tx-2020-en-r&anchor=para_118_e_vi&doctype=Standard -URIDate 2020-01-01 + Details
Name: | ifrs-full_AmortisationIntangibleAssetsOtherThanGoodwill
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | na
Period Type: | duration

X
- References No definition available. + Details
Name: | ifrs-full_CashFlowsFromUsedInOperatingActivitiesAbstract
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The cash from (used in) the entity's operations. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Name IAS -Number 7 -IssueDate 2020-01-01 -Section A Statement of cash flows for an entity other than a financial institution -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=7&code=ifrs-tx-2020-en-r&doctype=Illustrative%20Examples&dita_xref=IAS07_IE_A_TI -URIDate 2020-01-01 Reference 2: http://www.xbrl.org/2003/role/exampleRef -Name IAS -Number 7 -IssueDate 2020-01-01 -Paragraph 20 -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=7&code=ifrs-tx-2020-en-r&anchor=para_20&doctype=Standard -URIDate 2020-01-01 + Details
Name: | ifrs-full_CashFlowsFromUsedInOperations
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | na
Period Type: | duration

X
- Definition The amount of depreciation of right-of-use assets. [Refer: Depreciation and amortisation expense; Right-of-use assets] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 16 -IssueDate 2020-01-01 -Paragraph 53 -Subparagraph a -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=16&code=ifrs-tx-2020-en-r&anchor=para_53_a&doctype=Standard -URIDate 2020-01-01 + Details
Name: | ifrs-full_DepreciationRightofuseAssets
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | na
Period Type: | duration

X
- Definition The gain (loss) arising from the derecognition of financial assets measured at amortised cost. [Refer: Financial assets at amortised cost] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 1 -IssueDate 2020-01-01 -Paragraph 82 -Subparagraph aa -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_82_aa&doctype=Standard -URIDate 2020-01-01 + Details
Name: | ifrs-full_GainLossArisingFromDerecognitionOfFinancialAssetsMeasuredAtAmortisedCost
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The amount of impairment loss recognised in profit or loss for intangible assets other than goodwill. [Refer: Impairment loss recognised in profit or loss; Intangible assets other than goodwill] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 38 -IssueDate 2020-01-01 -Paragraph 118 -Subparagraph e -Clause iv -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=38&code=ifrs-tx-2020-en-r&anchor=para_118_e_iv&doctype=Standard -URIDate 2020-01-01 + Details
Name: | ifrs-full_ImpairmentLossRecognisedInProfitOrLossIntangibleAssetsOtherThanGoodwill
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | na
Period Type: | duration

X
- Definition Adjustments to reconcile profit (loss) to net cash flow from (used in) operating activities that the entity does not separately disclose in the same statement or note. [Refer: Adjustments to reconcile profit (loss)] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 7 -IssueDate 2020-01-01 -Paragraph 20 -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=7&code=ifrs-tx-2020-en-r&anchor=para_20&doctype=Standard -URIDate 2020-01-01 + Details
Name: | ifrs-full_OtherAdjustmentsToReconcileProfitLoss
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The total of income less expenses from continuing and discontinued operations, excluding the components of other comprehensive income. [Refer: Other comprehensive income] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 7 -IssueDate 2020-01-01 -Paragraph 18 -Subparagraph b -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=7&code=ifrs-tx-2020-en-r&anchor=para_18_b&doctype=Standard -URIDate 2020-01-01 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 1 -IssueDate 2020-01-01 -Paragraph 24 -Subparagraph b -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=1&code=ifrs-tx-2020-en-r&anchor=para_24_b&doctype=Standard -URIDate 2020-01-01 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 1 -IssueDate 2020-01-01 -Paragraph 32 -Subparagraph a -Clause ii -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=1&code=ifrs-tx-2020-en-r&anchor=para_32_a_ii&doctype=Standard -URIDate 2020-01-01 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 8 -IssueDate 2020-01-01 -Paragraph 28 -Subparagraph b -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=8&code=ifrs-tx-2020-en-r&anchor=para_28_b&doctype=Standard -URIDate 2020-01-01 Reference 5: http://www.xbrl.org/2003/role/exampleRef -Note Effective on first application of IFRS 9 -Name IFRS -Number 4 -IssueDate 2020-01-01 -Paragraph 39L -Subparagraph e -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=4&code=ifrs-tx-2020-en-b&anchor=para_39L_e&doctype=Standard -URIDate 2020-01-01 Reference 6: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 8 -IssueDate 2020-01-01 -Paragraph 23 -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=8&code=ifrs-tx-2020-en-r&anchor=para_23&doctype=Standard -URIDate 2020-01-01 Reference 7: http://www.xbrl.org/2003/role/exampleRef -Name IFRS -Number 12 -IssueDate 2020-01-01 -Paragraph B10 -Subparagraph b -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=12&code=ifrs-tx-2020-en-r&anchor=para_B10_b&doctype=Appendix&subtype=B -URIDate 2020-01-01 Reference 8: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 1 -IssueDate 2020-01-01 -Paragraph 106 -Subparagraph d -Clause i -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_106_d_i&doctype=Standard -URIDate 2020-01-01 Reference 9: http://www.xbrl.org/2003/role/exampleRef -Note Effective 2021-01-01 -Name IFRS -Number 17 -IssueDate 2020-01-01 -Paragraph 113 -Subparagraph b -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=17&code=ifrs-tx-2020-en-r&anchor=para_113_b&doctype=Standard -URIDate 2020-01-01 Reference 10: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 1 -IssueDate 2020-01-01 -Paragraph 81A -Subparagraph a -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_81A_a&doctype=Standard -URIDate 2020-01-01 + Details
Name: | ifrs-full_ProfitLoss
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Adjustment for increase decrease in other noncurrent assets. + References No definition available. + Details
Name: | kt_AdjustmentForIncreaseDecreaseInOtherNoncurrentAssets
Namespace Prefix: | kt_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Adjustments for decrease (increase) in other receivable + References No definition available. + Details
Name: | kt_AdjustmentsForDecreaseIncreaseInOtherReceivable
Namespace Prefix: | kt_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Adjustments for decrease (increase) in plan assets + References No definition available. + Details
Name: | kt_AdjustmentsForDecreaseIncreaseInPlanAssets
Namespace Prefix: | kt_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Adjustments for gain on disposal of available for sale fair value through profit or loss. + References No definition available. + Details
Name: | kt_AdjustmentsForGainOnDisposalOfAvailableForSaleFairValueThroughProfitOrLoss
Namespace Prefix: | kt_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Adjustments for gains (loss) on valuation and settlement of derivatives. + References No definition available. + Details
Name: | kt_AdjustmentsForGainsLossOnValuationAndSettlementOfDerivatives
Namespace Prefix: | kt_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Adjustments for increase decrease in other noncurrent liabilities. + References No definition available. + Details
Name: | kt_AdjustmentsForIncreaseDecreaseInOtherNoncurrentLiabilities
Namespace Prefix: | kt_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Adjustments for increase decrease in other payables. + References No definition available. + Details
Name: | kt_AdjustmentsForIncreaseDecreaseInOtherPayables
Namespace Prefix: | kt_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Adjustments for increase decrease in provision. + References No definition available. + Details
Name: | kt_AdjustmentsForIncreaseDecreaseInProvision
Namespace Prefix: | kt_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Adjustments for loss on disposal of intangible assets. + References No definition available. + Details
Name: | kt_AdjustmentsForLossOnDisposalOfIntangibleAssets
Namespace Prefix: | kt_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Adjustments for loss on foreign currency translation. + References No definition available. + Details
Name: | kt_AdjustmentsForLossOnForeignCurrencyTranslation
Namespace Prefix: | kt_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Adjustments for payments of severance benefits. + References No definition available. + Details
Name: | kt_AdjustmentsForPaymentsOfSeveranceBenefits
Namespace Prefix: | kt_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Adjustments for provision for severance benefits. + References No definition available. + Details
Name: | kt_AdjustmentsForProvisionForSeveranceBenefits
Namespace Prefix: | kt_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Adjustments for share of net profit of associates and joint ventures. + References No definition available. + Details
Name: | kt_AdjustmentsForShareOfNetProfitOfAssociatesAndJointVentures
Namespace Prefix: | kt_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Change in Operating Assets and Liabilities [abstract] + References No definition available. + Details
Name: | kt_ChangeInOperatingAssetsAndLiabilitiesAbstract
Namespace Prefix: | kt_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Gain (loss ) valuation of financial assets fair value of profit or loss. + References No definition available. + Details
Name: | kt_GainLossValuationOfFinancialAssetsFairValueOfProfitOrLoss
Namespace Prefix: | kt_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Gain on disposal of right-of-use assets. + References No definition available. + Details
Name: | kt_GainOnDisposalOfRightofuseAssets
Namespace Prefix: | kt_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Impairment losses on current assets held for sale. + References No definition available. + Details
Name: | kt_ImpairmentLossesOnCurrentAssetsHeldForSale
Namespace Prefix: | kt_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration