Principal assumptions on actuarial valuation (Details) - ₩ / shares	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017
Disclosure - Principal assumptions on actuarial valuation [Abstract]
Discount rate	2.24% ~ 2.90%	2.75% ~ 2.90%
Future salary and benefit levels	4.88%	4.88%
Weighted average duration	13.71	13.4

The expected rate of salary increases used as a significant actuarial assumption to determine the present value of a defined benefit obligation. [Refer: Defined benefit plans [member]; Defined benefit obligation, at present value; Actuarial assumptions [member]]

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 19
-IssueDate 2018-01-01
-Paragraph 144
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=19&date=2018-03-01&anchor=para_144&doctype=Standard
-URIDate 2018-03-16

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Namespace Prefix:	ifrs-full_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant