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

The increase (decrease) in the number of shares outstanding. [Refer: Number of shares outstanding]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 1
-IssueDate 2017-01-01
-Paragraph 79
-Subparagraph a
-Clause iv
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=1&date=2017-03-01&anchor=para_79_a_iv&doctype=Standard
-URIDate 2017-03-09

Name:	ifrs-full_IncreaseDecreaseInNumberOfSharesOutstanding
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

The nominal value of capital issued.

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Name IAS
-Number 1
-IssueDate 2017-01-01
-Paragraph 78
-Subparagraph e
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=1&date=2017-03-01&anchor=para_78_e&doctype=Standard
-URIDate 2017-03-09

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

The number of shares issued by the entity.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 1
-IssueDate 2017-01-01
-Paragraph 106
-Subparagraph d
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=1&date=2017-03-01&anchor=para_106_d&doctype=Standard
-URIDate 2017-03-09

Name:	ifrs-full_NumberOfSharesIssued
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

The number of shares that have been authorised and issued, reduced by treasury shares held. [Refer: Treasury shares]

Name:	ifrs-full_NumberOfSharesOutstanding
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

The nominal value per share.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 1
-IssueDate 2017-01-01
-Paragraph 79
-Subparagraph a
-Clause iii
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=1&date=2017-03-01&anchor=para_79_a_iii&doctype=Standard
-URIDate 2017-03-09

Name:	ifrs-full_ParValuePerShare
Namespace Prefix:	ifrs-full_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

The decrease in equity resulting from a reduction in issued capital. [Refer: Issued capital]

Name:	ifrs-full_ReductionOfIssuedCapital
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Aggregate Amount of Issuance of Securities

No definition available.

Name:	tef_AggregateAmountofIssuanceofSecurities
Namespace Prefix:	tef_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Increase In Share Capital Maximum Duration

No definition available.

Name:	tef_IncreaseInShareCapitalMaximumDuration
Namespace Prefix:	tef_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

Maximum Authorized Issued Capital

No definition available.

Name:	tef_MaximumAuthorizedIssuedCapital
Namespace Prefix:	tef_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Proportion Of Share Capital Excluded From Pre-Emptive Subscription Rights

No definition available.

Name:	tef_ProportionOfShareCapitalExcludedFromPreEmptiveSubscriptionRights
Namespace Prefix:	tef_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

Proportion Of Shares Acquired To Treasury Shares Held Requirement

No definition available.