Employment benefit obligations (Details) - KRW (₩) ₩ in Millions	Dec. 31, 2020	Dec. 31, 2019
Employment Benefits [Abstract]
Net defined benefit asset	₩ (7,231)	₩ (1,047)
Net defined benefit obligations	1,907,013	1,925,134
Other long-term employee benefit obligations	3,847	4,720
Employee benefits liabilities, net	₩ 1,903,629	₩ 1,928,807

The amount of deficit or surplus in a defined benefit plan, adjusted for any effect of limiting a net defined benefit asset to the asset ceiling. [Refer: Defined benefit plans [member]]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 19
-IssueDate 2020-01-01
-Paragraph 140
-Subparagraph a
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=19&code=ifrs-tx-2020-en-r&anchor=para_140_a&doctype=Standard
-URIDate 2020-01-01

Name:	ifrs-full_LiabilityAssetOfDefinedBenefitPlans
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant