Hybrid Bonds - Summary of Hybrid Bonds (Detail) - KRW (₩) ₩ in Millions	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017
Series hybrid bonds	₩ 398,759	₩ 398,518
Series 2-1 hybrid bonds [member]
Type	Unsecured subordinated bearer bond
Issuance date	Jun. 07, 2018
Maturity	June 7, 2078
Annual interest rate(%)	3.70%
Series hybrid bonds	₩ 300,000
Series 2-2 hybrid bonds [member]
Type	Unsecured subordinated bearer bond
Issuance date	Jun. 07, 2018
Maturity	June 7, 2078
Annual interest rate(%)	3.65%
Series hybrid bonds	₩ 100,000
Issuance costs [Member]
Series hybrid bonds	₩ (1,241)

The interest rate on borrowings. [Refer: Borrowings]

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IFRS
-Number 7
-IssueDate 2018-01-01
-Paragraph 7
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=7&date=2018-03-01&anchor=para_7&doctype=Standard
-URIDate 2018-03-16

+ Details

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

- Definition

The maturity of borrowings. [Refer: Borrowings]

+ References

+ Details

Name:	ifrs-full_BorrowingsMaturity
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The description of the rights, preferences and restrictions that are attached to a category of equity interest by an entity without share capital. [Refer: Share capital [member]; Other equity interest]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 1
-IssueDate 2018-01-01
-Paragraph 80
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=1&date=2018-03-01&anchor=para_80&doctype=Standard
-URIDate 2018-03-16

+ Details

Name:	ifrs-full_DescriptionOfOtherEquityInterest
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The amount of equity interest of an entity without share capital that the entity does not separately disclose in the same statement or note.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Name IAS
-Number 1
-IssueDate 2018-01-01
-Paragraph 78
-Subparagraph e
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=1&date=2018-03-01&anchor=para_78_e&doctype=Standard
-URIDate 2018-03-16

+ Details

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

- Definition

Borrowings issuance date.

+ References

No definition available.

+ Details

Name:	skm_BorrowingIssuanceDate
Namespace Prefix:	skm_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	ifrs-full_ComponentsOfEquityAxis=skm_HybridBondSeriesTwoToOneMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_ComponentsOfEquityAxis=skm_HybridBondSeriesTwoToTwoMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_CarryingAmountAccumulatedDepreciationAmortisationAndImpairmentAndGrossCarryingAmountAxis=skm_IssuanceCostMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: