XML 212 R200.htm IDEA: XBRL DOCUMENT v3.19.1

Related Party Transactions - Summary of Significant Transactions with Related Parties (Detail) - KRW (₩) ₩ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Disclosure of transactions between related parties [line items]
Sales	₩ 24,312	₩ 37,282	₩ 8,009
Purchases	128,252	156,259	177,666
KT Wibro Infra Co., Ltd. [member]
Disclosure of transactions between related parties [line items]
Sales			11
Purchases			391
Smart Channel Co., Ltd. [member]
Disclosure of transactions between related parties [line items]
Sales			766
K-Realty CR-REITs No.1 [member]
Disclosure of transactions between related parties [line items]
Sales	2,088	2,233	1,989
Purchases	31,984	35,532	37,469
MOS GS Co., Ltd. [member]
Disclosure of transactions between related parties [line items]
Sales	493	704	663
Purchases	12,023	16,946	17,361
MOS Daegu Co., Ltd. [member]
Disclosure of transactions between related parties [line items]
Sales	229	335	291
Purchases	8,775	8,514	12,220
MOS Chungcheong Co., Ltd. [member]
Disclosure of transactions between related parties [line items]
Sales	540	455	408
Purchases	9,159	15,542	13,469
MOS Gangnam Co., Ltd. [member]
Disclosure of transactions between related parties [line items]
Sales	333	484	412
Purchases	11,549	16,380	15,797
MOS GB Co., Ltd. [member]
Disclosure of transactions between related parties [line items]
Sales	1,378	987	891
Purchases	16,519	21,651	21,802
MOS BS Co., Ltd. [member]
Disclosure of transactions between related parties [line items]
Sales	324	460	441
Purchases	11,193	15,957	15,346
MOS Honam Co., Ltd. [member]
Disclosure of transactions between related parties [line items]
Sales	331	493	418
Purchases	10,499	14,294	14,389
Others [member]
Disclosure of transactions between related parties [line items]
Sales	2,888	1,149	1,719
Purchases	9,547	11,384	₩ 29,422
K Bank Inc. [member]
Disclosure of transactions between related parties [line items]
Sales	15,705	29,939
Purchases	7,004	59
NgeneBio [member]
Disclosure of transactions between related parties [line items]
Sales	₩ 3	₩ 43

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

X

- Definition

The amount of goods purchased by the entity in related party transactions. [Refer: Related parties [member]]

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Name IAS
-Number 24
-IssueDate 2018-01-01
-Paragraph 21
-Subparagraph a
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=24&date=2018-03-01&anchor=para_21_a&doctype=Standard
-URIDate 2018-03-16

+ Details

Name:	ifrs-full_PurchasesOfGoodsRelatedPartyTransactions
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

X

- Definition

The amount of revenue arising from the sale of goods in related party transactions. [Refer: Revenue; Related parties [member]]

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Name IAS
-Number 24
-IssueDate 2018-01-01
-Paragraph 21
-Subparagraph a
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=24&date=2018-03-01&anchor=para_21_a&doctype=Standard
-URIDate 2018-03-16

+ Details

Name:	ifrs-full_RevenueFromSaleOfGoodsRelatedPartyTransactions
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

X

- Details

Name:	ifrs-full_CategoriesOfRelatedPartiesAxis=kt_KtWibroInfraCompanyLimitedMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	ifrs-full_CategoriesOfRelatedPartiesAxis=kt_SmartChannelCompanyLimitedMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	ifrs-full_CategoriesOfRelatedPartiesAxis=kt_KrealtyCrReitsNoMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	ifrs-full_CategoriesOfRelatedPartiesAxis=kt_MosGsCompanyLimitedMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	ifrs-full_CategoriesOfRelatedPartiesAxis=kt_MosDaeguCompanyLimitedMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	ifrs-full_CategoriesOfRelatedPartiesAxis=kt_MosChungcheongCompanyLimitedMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	ifrs-full_CategoriesOfRelatedPartiesAxis=kt_MosGangnamCompanyLimitedMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	ifrs-full_CategoriesOfRelatedPartiesAxis=kt_MosGbCompanyLimitedMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	ifrs-full_CategoriesOfRelatedPartiesAxis=kt_MosBsCompanyLimitedMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	ifrs-full_CategoriesOfRelatedPartiesAxis=kt_MosHonamCompanyLimitedMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	ifrs-full_CategoriesOfRelatedPartiesAxis=ifrs-full_OtherRelatedPartiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	ifrs-full_CategoriesOfRelatedPartiesAxis=kt_KBankIncMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	ifrs-full_CategoriesOfRelatedPartiesAxis=kt_NgeneBioMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: