Name:	dei_EntityInformationLineItems
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Data Type:	xbrli:stringItemType
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Period Type:	duration

The interest rate on borrowings. [Refer: Borrowings]

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IFRS
-Number 7
-IssueDate 2017-01-01
-Paragraph 7
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=7&date=2017-03-01&anchor=para_7&doctype=Standard
-URIDate 2017-03-09

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Data Type:	num:percentItemType
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The maturity of borrowings. [Refer: Borrowings]

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Data Type:	xbrli:stringItemType
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The amount of loans received.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 1
-IssueDate 2017-01-01
-Paragraph 112
-Subparagraph c
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=1&date=2017-03-01&anchor=para_112_c&doctype=Standard
-URIDate 2017-03-09

Name:	ifrs-full_LoansReceived
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Data Type:	xbrli:monetaryItemType
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Period Type:	instant

The nominal or face amount of a financial instrument, used to calculate payments made on that instrument.

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Data Type:	xbrli:monetaryItemType
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The cash outflow to acquire or redeem entity's shares.

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Name IAS
-Number 7
-IssueDate 2017-01-01
-Paragraph 17
-Subparagraph b
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=7&date=2017-03-01&anchor=para_17_b&doctype=Standard
-URIDate 2017-03-09

Name:	ifrs-full_PaymentsToAcquireOrRedeemEntitysShares
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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Proceeds From Issuance Of Bonds

No definition available.

Name:	tef_ProceedsFromIssuanceOfDebenturesBondsAndOtherDebts
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Namespace Prefix:
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Name:	ifrs-full_NonadjustingEventsAfterReportingPeriodAxis=ifrs-full_EnteringIntoSignificantCommitmentsOrContingentLiabilitiesMember
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Name:	dei_LegalEntityAxis=tef_TelefonicaDeutschlandHoldingA.G.Member
Namespace Prefix:
Data Type:	na
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Name:	dei_LegalEntityAxis=tef_TelefonicaEmisionesS.A.U.Member
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