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Data Type:	xbrli:stringItemType
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 2019-01-01
-Paragraph 78
-Subparagraph e
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2019-en-r&anchor=para_78_e&doctype=Standard
-URIDate 2019-03-27

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

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

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 1
-IssueDate 2019-01-01
-Paragraph 79
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-Clause iv
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2019-en-r&anchor=para_79_a_iv&doctype=Standard
-URIDate 2019-03-27

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 2019-01-01
-Paragraph 79
-Subparagraph a
-Clause iii
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2019-en-r&anchor=para_79_a_iii&doctype=Standard
-URIDate 2019-03-27

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

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.