Cash and cash equivalents and Investments and Additional information on the consolidated statements of cash flows - Main non-cash operating transactions (Details) - ARS ($) $ in Millions	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Main non-cash operating transactions:
Offsetting of capitalized trade receivables of Tuves Paraguay acquisition	$ 149
Offsetting of tax on personal property - on behalf of Shareholders		$ 8	$ 15
Income tax offset with VAT and internal taxes			50
Offsetting of other receivables with regulatory provisions	1	27
VAT offset with income tax payments		54
SAC acquisitions offset with trade receivables	$ 313	305	$ 212
Other receivables of PP&E sales offset with trade payables		$ 25

The amount represents the offsetting of capitalized trade receivables on Tuves Paraguay acquisition.

No definition available.

Name:	teo_CapitalizedTradeReceivablesOffsettingOnAcquisition
Namespace Prefix:	teo_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

No definition available

No definition available.

Name:	teo_CashFlowNoncashOperatingActivitiesAbstract
Namespace Prefix:	teo_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

The amount represents the income tax offset with VAT and internal taxes.

No definition available.

Name:	teo_IncomeTaxOffsetWithVatAndInternalTaxes
Namespace Prefix:	teo_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

The amount represents the provisions offset for other receivables.

No definition available.

Name:	teo_OtherReceivablesOffsetWithProvisions
Namespace Prefix:	teo_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

The amount of receivables from sale of property, plant and equipment offset with trade payables.

No definition available.

Name:	teo_ReceivablesFromPropertyPlantAndEquipmentSalesOffsetWithTradePayables
Namespace Prefix:	teo_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

The amount represents the offset of subscriber acquisition costs with trade receivables.

No definition available.

Name:	teo_SubscriberAcquisitionCostsOffsetWithTradeReceivables
Namespace Prefix:	teo_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

The amount represents the offsetting of tax on personal property, on behalf of shareholders.

No definition available.

Name:	teo_TaxOffsettingOnPersonalPropertyOnBehalfOfShareholders
Namespace Prefix:	teo_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

The amount represents the VAT offset with income taxes.

No definition available.

Name:	teo_VatOffsetWithIncomeTaxes
Namespace Prefix:	teo_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration