Statements of Cash Flows - Significant Non-cash Transactions (Detail) - KRW (₩) ₩ in Millions	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Significant Non-cash Investing and Financing Transactions [abstract]
Increase in accounts payable - other relating to acquisition of property and equipment and intangible assets	₩ 1,162,301	₩ 44,214	₩ 1,511,913
Investment in subsidiary from comprehensive stock exchange	₩ 129,595

Non-cash transactions increase of accounts payable other related to acquisition of property and equipment and intangible assets.

No definition available.

Name:	skm_NoncashTransactionsIncreaseDecreaseOfAccountsPayableOtherRelatedToAcquisitionOfPropertyAndEquipmentAndIntangibleAssets
Namespace Prefix:	skm_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration