XML 186 R174.htm IDEA: XBRL DOCUMENT v3.21.1

Share-based Payments - Summary of Changes in the Number of Stock Options and the Weighted-Average Exercise Price (Detail)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Disclosure of terms and conditions of share-based payment arrangement [Line Items]
Beginning	372,023	353,325
Granted	1,418,961	372,023
Expired	241,548	256,543
Exercised	1,150,580	96,782
Ending	398,856	372,023
12th grant [member]
Disclosure of terms and conditions of share-based payment arrangement [Line Items]
Beginning		353,325
Expired		256,543
Exercised		96,782
13th grant [member]
Disclosure of terms and conditions of share-based payment arrangement [Line Items]
Beginning	372,023
Granted		372,023
Expired	241,548
Exercised	130,475
Ending		372,023
14Th grant [Member]
Disclosure of terms and conditions of share-based payment arrangement [Line Items]
Granted	398,856
Ending	398,856
Employee wage negotiation [Member]
Disclosure of terms and conditions of share-based payment arrangement [Line Items]
Granted	1,020,105
Exercised	1,020,105

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

X

- Definition

The number of share options outstanding in a share-based payment arrangement.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 2
-IssueDate 2020-01-01
-Paragraph 45
-Subparagraph d
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=2&code=ifrs-tx-2020-en-r&anchor=para_45_d&doctype=Standard
-URIDate 2020-01-01

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 2
-IssueDate 2020-01-01
-Paragraph 45
-Subparagraph b
-Clause i
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=2&code=ifrs-tx-2020-en-r&anchor=para_45_b_i&doctype=Standard
-URIDate 2020-01-01

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 2
-IssueDate 2020-01-01
-Paragraph 45
-Subparagraph b
-Clause vi
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=2&code=ifrs-tx-2020-en-r&anchor=para_45_b_vi&doctype=Standard
-URIDate 2020-01-01

+ Details

Name:	ifrs-full_NumberOfOutstandingShareOptions
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	instant

X

- Definition

The number of share options exercised in a share-based payment arrangement.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 2
-IssueDate 2020-01-01
-Paragraph 45
-Subparagraph b
-Clause iv
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=2&code=ifrs-tx-2020-en-r&anchor=para_45_b_iv&doctype=Standard
-URIDate 2020-01-01

+ Details

Name:	ifrs-full_NumberOfShareOptionsExercisedInSharebasedPaymentArrangement
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	duration

X

- Definition

The number of share options expired in a share-based payment arrangement.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 2
-IssueDate 2020-01-01
-Paragraph 45
-Subparagraph b
-Clause v
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=2&code=ifrs-tx-2020-en-r&anchor=para_45_b_v&doctype=Standard
-URIDate 2020-01-01

+ Details

Name:	ifrs-full_NumberOfShareOptionsExpiredInSharebasedPaymentArrangement
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	duration

X

- Definition

The number of share options granted in a share-based payment arrangement.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 2
-IssueDate 2020-01-01
-Paragraph 45
-Subparagraph b
-Clause ii
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=2&code=ifrs-tx-2020-en-r&anchor=para_45_b_ii&doctype=Standard
-URIDate 2020-01-01

+ Details

Name:	ifrs-full_NumberOfShareOptionsGrantedInSharebasedPaymentArrangement
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	duration

X

- Details

Name:	ifrs-full_TypesOfSharebasedPaymentArrangementsAxis=kt_TwelvethGrantMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	ifrs-full_TypesOfSharebasedPaymentArrangementsAxis=kt_ThirteenthGrantMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	ifrs-full_TypesOfSharebasedPaymentArrangementsAxis=kt_FourteenthGrantMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	ifrs-full_TypesOfSharebasedPaymentArrangementsAxis=kt_EmployeeWageNegotiationMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: