Derivative Financial Instruments and Risk Management Policies - Liquidity Risk (Details) - EUR (€) € in Millions	12 Months Ended
Dec. 31, 2024	Dec. 31, 2023
Disclosure of financial liabilities [line items]
Average maturity of net financial debt	11 years 4 months 2 days
Period to pay all commitments	12 months
Net debt held as a hedging instrument	€ 27,161
Current lease liabilities	2,226	€ 2,239
Non-current financial liabilities	€ 10,634
Non-current financial liabilities, term	2 years
Telefónica, S.A.
Disclosure of financial liabilities [line items]
Total carrying amount	€ 38,782	37,061
Current lease liabilities	€ 2,226	€ 2,239
Minimum
Disclosure of financial liabilities [line items]
Average maturity of net financial debt	6 years
Less than 1 year \| Telefónica, S.A.
Disclosure of financial liabilities [line items]
Total carrying amount	€ 5,590

The amount of current lease liabilities. [Refer: Lease liabilities]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
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-IssueDate 2024-01-01
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Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with members defined in one or many axes of the table.

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The amount of liabilities that are: (a) a contractual obligation: (i) to deliver cash or another financial asset to another entity; or (ii) to exchange financial assets or financial liabilities with another entity under conditions that are potentially unfavourable to the entity; or (b) a contract that will, or may be, settled in the entity’s own equity instruments and is: (i) a non-derivative for which the entity is, or may be, obliged to deliver a variable number of the entity’s own equity instruments; or (ii) a derivative that will, or may be, settled other than by the exchange of a fixed amount of cash or another financial asset for a fixed number of the entity’s own equity instruments. For this purpose, rights, options or warrants to acquire a fixed number of the entity’s own equity instruments for a fixed amount of any currency are equity instruments if the entity offers the rights, options or warrants pro rata to all of its existing owners of the same class of its own non-derivative equity instruments. Also, for those purposes the entity’s own equity instruments do not include puttable financial instruments that are classified as equity instruments in accordance with paragraphs 16A-16B of IAS 32, instruments that impose on the entity an obligation to deliver to another party a pro rata share of the net assets of the entity only on liquidation and are classified as equity instruments in accordance with paragraphs 16C-16D of IAS 32, or instruments that are contracts for the future receipt or delivery of the entity’s own equity instruments. As an exception, an instrument that meets the definition of a financial liability is classified as an equity instrument if it has all the features and meets the conditions in paragraphs 16A-16B or paragraphs 16C-16D of IAS 32. [Refer: Classes of financial instruments [domain]; Financial assets; Derivatives [member]]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 7
-IssueDate 2024-01-01
-Paragraph 25
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The amount of a hedging instrument, recognised as a liability. [Refer: Hedging instruments [domain]]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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-IssueDate 2024-01-01
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Average Maturity Of Net Financial Debt

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Period to Pay All Commitments

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