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The increase (decrease) in a defined benefit obligation that would have been caused by a decrease in a significant actuarial assumption that was reasonably possible at the end of the reporting period. [Refer: Actuarial assumptions [member]]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 19
-IssueDate 2019-01-01
-Paragraph 145
-Subparagraph a
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=19&code=ifrs-tx-2019-en-r&anchor=para_145_a&doctype=Standard
-URIDate 2019-03-27

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The increase (decrease) in a defined benefit obligation that would have been caused by an increase in a significant actuarial assumption that was reasonably possible at the end of the reporting period. [Refer: Actuarial assumptions [member]]

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Namespace Prefix:	ifrs-full_
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Decrease In Income Due To Reasonably Possible Increase In Actuarial Assumption

No definition available.

Name:	tef_DecreaseInIncomeDueToReasonablyPossibleIncreaseInActuarialAssumption
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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Increase In Income Due To Reasonably Possible Decrease In Actuarial Assumption

No definition available.