Inventories - Details of Inventories (Detail) - KRW (₩) ₩ in Millions	Dec. 31, 2018	Dec. 31, 2017
Disclosure of inventories [Line Items]
Merchandise	₩ 259,524	₩ 243,975
Finished goods	1,009	1,332
Work in process	3,647	950
Raw materials	9,023	7,177
Supplies	14,850	18,969
Inventories	288,053	272,403
Gross amount [member]
Disclosure of inventories [Line Items]
Merchandise	268,366	251,463
Finished goods	1,260	1,889
Work in process	3,985	1,906
Raw materials	11,729	10,426
Supplies	14,850	18,969
Inventories	300,190	284,653
Accumulated impairment [member]
Disclosure of inventories [Line Items]
Merchandise	(8,842)	(7,488)
Finished goods	(251)	(557)
Work in process	(338)	(956)
Raw materials	(2,706)	(3,249)
Inventories	₩ (12,137)	₩ (12,250)

A classification of current inventory representing the amount of goods that have completed the production process and are held for sale in the ordinary course of business. [Refer: Inventories]

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 2
-IssueDate 2018-01-01
-Paragraph 37
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=2&date=2018-03-01&anchor=para_37&doctype=Standard
-URIDate 2018-03-16

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Name IAS
-Number 1
-IssueDate 2018-01-01
-Paragraph 78
-Subparagraph c
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=1&date=2018-03-01&anchor=para_78_c&doctype=Standard
-URIDate 2018-03-16

+ Details

Name:	ifrs-full_FinishedGoods
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The amount of current inventories. [Refer: Inventories]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 2
-IssueDate 2018-01-01
-Paragraph 36
-Subparagraph b
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=2&date=2018-03-01&anchor=para_36_b&doctype=Standard
-URIDate 2018-03-16

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 1
-IssueDate 2018-01-01
-Paragraph 54
-Subparagraph g
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=1&date=2018-03-01&anchor=para_54_g&doctype=Standard
-URIDate 2018-03-16

Reference 3: http://www.xbrl.org/2003/role/exampleRef
-Name IAS
-Number 1
-IssueDate 2018-01-01
-Paragraph 68
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=1&date=2018-03-01&anchor=para_68&doctype=Standard
-URIDate 2018-03-16

+ Details

Name:	ifrs-full_Inventories
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

A classification of current inventory representing the amount of goods acquired for resale. [Refer: Inventories]

+ References

+ Details

Name:	ifrs-full_Merchandise
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

A classification of current inventory representing the amount of supplies to be used for the production process. [Refer: Inventories]

+ References

+ Details

Name:	ifrs-full_ProductionSupplies
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

A classification of current inventory representing the amount of assets to be consumed in the production process or in the rendering of services. [Refer: Inventories]

+ References

+ Details

Name:	ifrs-full_RawMaterials
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

A classification of current inventory representing the amount of assets currently in production, which require further processes to be converted into finished goods or services. [Refer: Current finished goods; Inventories]

+ References

+ Details

Name:	ifrs-full_WorkInProgress
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Disclosure of inventories.

+ References

No definition available.

+ Details

Name:	skm_DisclosureOfInventoriesLineItems
Namespace Prefix:	skm_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

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

- Details

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