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Changes in Accounting Policies - Additional Information (Detail) - KRW (₩) ₩ in Millions		12 Months Ended
	Jan. 01, 2018	Dec. 31, 2018
Disclosure of expected impact of initial application of new standards or interpretations [line items]
Description of practical expedients used for incremental cost of obtaining contract		As a practical expedient, the Group recognizes the incremental costs of obtaining a contracts as an expense when incurred if the amortization period of the asset is one year or less.
Increase (decrease) in prepaid expenses	₩ 1,285,443	₩ 1,444,822
Increase (decrease) due to application of IFRS 15 [member]
Disclosure of expected impact of initial application of new standards or interpretations [line items]
Increase (decrease) in contract assets	421,131	398,797
Increase (decrease) in contract liabilities	₩ 282,836	₩ 347,461

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- Definition

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+ References

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- Definition

The description of the practical expedients that have been used when applying IFRS 15 retrospectively.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 15
-IssueDate 2018-01-01
-Paragraph C6
-Subparagraph a
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=15&date=2018-03-01&anchor=para_C6_a&doctype=Appendix&seq=3
-URIDate 2018-03-16

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- Definition

The increase (decrease) in contract assets resulting from cumulative catch-up adjustments to revenue. [Refer: Contract assets; Revenue]

+ References

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-Name IFRS
-Number 15
-IssueDate 2018-01-01
-Paragraph 118
-Subparagraph b
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=15&date=2018-03-01&anchor=para_118_b&doctype=Standard
-URIDate 2018-03-16

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- Definition

The increase (decrease) in contract liabilities resulting from cumulative catch-up adjustments to revenue. [Refer: Contract liabilities; Revenue]

+ References

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-Name IFRS
-Number 15
-IssueDate 2018-01-01
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-Subparagraph b
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-URIDate 2018-03-16

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Increase (decrease) in prepaid expenses.

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