Retained Earnings - Summary of Retained Earnings (Detail) - KRW (₩) ₩ in Millions	Dec. 31, 2020	Dec. 31, 2019
Miscellaneous equity [abstract]
Legal reserve	₩ 782,249	₩ 782,249
Voluntary reserves	4,651,362	4,651,362
Unappropriated retained earnings	6,721,809	6,157,305
Total	₩ 12,155,420	₩ 11,590,916

A component of equity representing the entity's cumulative undistributed earnings or deficit.

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Name IAS
-Number 1
-IssueDate 2020-01-01
-Paragraph 78
-Subparagraph e
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_78_e&doctype=Standard
-URIDate 2020-01-01

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Name IAS
-Number 1
-IssueDate 2020-01-01
-Paragraph IG6
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_IG6&doctype=Implementation%20Guidance
-URIDate 2020-01-01

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