Intangible Assets - Details of the Changes in Intangible Assets (Parenthetical) (Detail) - KRW (₩) ₩ in Millions	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017
Disclosure of detailed information about intangible assets [line items]
Impairment loss	₩ (60,281)	₩ (18,493)
Life and Security Holdings Co., Ltd. [member]
Disclosure of detailed information about intangible assets [line items]
Indefinite lived intangible assets	₩ 374,096

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]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 38
-IssueDate 2018-01-01
-Paragraph 118
-Subparagraph e
-Clause iv
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=38&date=2018-03-01&anchor=para_118_e_iv&doctype=Standard
-URIDate 2018-03-16

Name:	ifrs-full_ImpairmentLossRecognisedInProfitOrLossIntangibleAssetsOtherThanGoodwill
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	duration