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Appendix I: Scope of Consolidation - Main Consolidated Companies of the Telefonica Group (Details)
€ in Millions, ₨ in Millions, лв in Millions, дин in Millions, £ in Millions, kr in Millions, kr in Millions, kr in Millions, VEF in Millions, SFr in Millions, S/ in Millions, R$ in Millions, $ in Millions, $ in Millions, $ in Millions, $ in Millions, $ in Millions, $ in Millions
 12 Months Ended
Dec. 31, 2023
EUR (€)
Dec. 31, 2023
BRL (R$)
Dec. 31, 2023
VEF
Dec. 31, 2023
COP ($)
Dec. 31, 2023
MXN ($)
Dec. 31, 2023
USD ($)
Dec. 31, 2023
ARS ($)
Dec. 31, 2023
CLP ($)
Dec. 31, 2023
PEN (S/)
Dec. 31, 2023
UYU ($)
Dec. 31, 2023
GBP (£)
Dec. 31, 2023
BGN (лв)
Dec. 31, 2023
INR (₨)
Dec. 31, 2023
SEK (kr)
Dec. 31, 2023
CHF (SFr)
Dec. 31, 2023
DKK (kr)
Dec. 31, 2023
NOK (kr)
Dec. 31, 2023
RSD (дин)
Dec. 31, 2022
EUR (€)
Dec. 31, 2021
EUR (€)
Dec. 31, 2020
EUR (€)
Disclosure of subsidiaries [line items]                                          
Equity € 27,096                                   € 31,708 € 28,684 € 18,260
Investments accounted for by the equity method 8,590                                   € 11,587    
Telefónica de España, S.A.U. Telecommunications service provider                                          
Disclosure of subsidiaries [line items]                                          
Equity € 1,024                                        
Proportion of ownership interest (as a percent) 100.00%                                        
Telefónica Móviles España, S.A.U. Wireless communications services provider                                          
Disclosure of subsidiaries [line items]                                          
Equity € 209                                        
Proportion of ownership interest (as a percent) 100.00%                                        
Teleinformática y Comunicaciones, S.A.U. (Telyco) Promotion, marketing and distribution of telephone and telematic equipment and services                                          
Disclosure of subsidiaries [line items]                                          
Equity € 8                                        
Proportion of ownership interest (as a percent) 100.00%                                        
Telefónica Soluciones de Informática y Com. de España S.A.U. Telecommunications systems, networks and infrastructure engineering                                          
Disclosure of subsidiaries [line items]                                          
Equity € 2                                        
Proportion of ownership interest (as a percent) 100.00%                                        
Telefónica Soluciones de Outsourcing, S.A.U. Promotion and networks management                                          
Disclosure of subsidiaries [line items]                                          
Equity € 1                                        
Proportion of ownership interest (as a percent) 100.00%                                        
Telefónica Servicios Integrales de Distribución S.A.U. Logistic service provider                                          
Disclosure of subsidiaries [line items]                                          
Equity € 2                                        
Proportion of ownership interest (as a percent) 100.00%                                        
Telefónica España Filiales, S.A.U. Organization and operation of multimedia service-related business                                          
Disclosure of subsidiaries [line items]                                          
Equity € 226                                        
Proportion of ownership interest (as a percent) 100.00%                                        
Telefónica Servicios Audiovisuales, S.A.U. Provision of all type of audiovisual telecommunications services                                          
Disclosure of subsidiaries [line items]                                          
Equity € 6                                        
Proportion of ownership interest (as a percent) 100.00%                                        
Telefónica Broadcast Services, S.L.U. DSNG-based transmission and operation services                                          
Disclosure of subsidiaries [line items]                                          
Equity € 0                                        
Proportion of ownership interest (as a percent) 100.00%                                        
TBSC Barcelona Producciones, S.L.U. Provision of audiovisual telecommunications services                                          
Disclosure of subsidiaries [line items]                                          
Equity € 0                                        
Proportion of ownership interest (as a percent) 100.00%                                        
Telefónica Audiovisual Digital, S.L.U. Provision of all type of audiovisual telecommunications services                                          
Disclosure of subsidiaries [line items]                                          
Equity € 46                                        
Proportion of ownership interest (as a percent) 100.00%                                        
Telefónica Global Technology, S.A.U. Global management and operation of IT systems                                          
Disclosure of subsidiaries [line items]                                          
Equity € 16                                        
Proportion of ownership interest (as a percent) 100.00%                                        
Telefónica Educación Digital, S.L.U. Vertical e-learning portal                                          
Disclosure of subsidiaries [line items]                                          
Equity € 1                                        
Proportion of ownership interest (as a percent) 100.00%                                        
Bluevia Fibra, S.L. Operations and exploitation of FTTH network and other connectivity services.                                          
Disclosure of subsidiaries [line items]                                          
Equity € 68                                        
Proportion of ownership interest (as a percent) 55.00%                                        
Bluevia Fibra, S.L. Operations and exploitation of FTTH network and other connectivity services. | Telefónica España Filiales, S.A                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 30.00%                                        
Bluevia Fibra, S.L. Operations and exploitation of FTTH network and other connectivity services. | Telefónica Infra, S.L.U. Sociedad holding                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 25.00%                                        
Solar360 Soluciones de Instalacion y Mantenimiento S.L. Marketing and management in the installation, sale and maintenance of photovoltaic equipment                                          
Disclosure of subsidiaries [line items]                                          
Equity € 0                                        
Proportion of ownership interest (as a percent) 51.00%                                        
Telefónica Ingeniería de Seguridad, S.A.U. Security services and systems                                          
Disclosure of subsidiaries [line items]                                          
Equity € 8                                        
Proportion of ownership interest (as a percent) 100.00%                                        
Telefónica Deutschland Holding, A.G.                                          
Disclosure of subsidiaries [line items]                                          
Equity € 2,975                                        
Proportion of ownership interest (as a percent) 82.43%                                        
Telefónica Deutschland Holding, A.G. | Telefónica Germany Holdings Limited                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 69.22%                                        
Telefónica Deutschland Holding, A.G. | Telefónica, S.A.                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 13.20%                                        
Telefónica Germany GmbH & Co. OHG Wireless communications services operator                                          
Disclosure of subsidiaries [line items]                                          
Equity € 51                                        
Proportion of ownership interest (as a percent) 82.43%                                        
Telefónica Germany GmbH & Co. OHG Wireless communications services operator | Telefónica Deutschland Holding A.G.                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 82.42%                                        
Telefónica Germany GmbH & Co. OHG Wireless communications services operator | T Germany Management GmbH                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 0.01%                                        
E-Plus Service GmbH Wireless communications services operator                                          
Disclosure of subsidiaries [line items]                                          
Equity € 0                                        
Proportion of ownership interest (as a percent) 82.43%                                        
Telefónica Germany Business Sales GmbH Technological and consulting services in Big Data provider                                          
Disclosure of subsidiaries [line items]                                          
Equity € 0                                        
Proportion of ownership interest (as a percent) 82.43%                                        
O2 Telefónica Deutschland Finanzierungs GmbH Integrated cash management, consulting and financial support for Group companies                                          
Disclosure of subsidiaries [line items]                                          
Equity € 0                                        
Proportion of ownership interest (as a percent) 82.43%                                        
Telefónica Brazil                                          
Disclosure of subsidiaries [line items]                                          
Equity | R$   R$ 63,571                                      
Proportion of ownership interest (as a percent) 75.29%                                        
Telefónica Brazil | Telefónica, S.A.                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 38.39%                                        
Telefónica Brazil | Telefónica Latinoamérica Holding, S.L.                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 36.85%                                        
Telefónica Brazil | Telefónica Chile, S.A.                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 0.06%                                        
Terra Networks Brasil, Ltda. ISP and portal                                          
Disclosure of subsidiaries [line items]                                          
Equity | R$   159                                      
Proportion of ownership interest (as a percent) 75.29%                                        
Telefônica Infraestructura e Segurança Ltda. Servicios y sistemas de seguridad                                          
Disclosure of subsidiaries [line items]                                          
Equity | R$   309                                      
Proportion of ownership interest (as a percent) 75.29%                                        
Vivo ventures fundo de investimento em participacoes multiestrategia. Investment funds                                          
Disclosure of subsidiaries [line items]                                          
Equity | R$   100                                      
Proportion of ownership interest (as a percent) 75.78%                                        
Vivo ventures fundo de investimento em participacoes multiestrategia. Investment funds | Telefônica Brasil, S.A.                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 73.78%                                        
Vivo ventures fundo de investimento em participacoes multiestrategia. Investment funds | Telefonica Open Innovation S.L.U. Talent identification and development in ICT.                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 2.00%                                        
Vale Saúde, Administradora de Cartões Ltda. Provision of health services                                          
Disclosure of subsidiaries [line items]                                          
Equity | R$   7                                      
Proportion of ownership interest (as a percent) 75.29%                                        
Telefónica Hispanoamérica, S.A.U. Sociedad holding                                          
Disclosure of subsidiaries [line items]                                          
Equity € 97                                        
Proportion of ownership interest (as a percent) 100.00%                                        
TLH Holdco, S.L.U. Sociedad holding                                          
Disclosure of subsidiaries [line items]                                          
Equity € 87                                        
Proportion of ownership interest (as a percent) 100.00%                                        
Telefónica Venezolana, C.A. Wireless communications operator                                          
Disclosure of subsidiaries [line items]                                          
Equity | VEF     VEF 1,375                                    
Proportion of ownership interest (as a percent) 100.00%                                        
Telefónica Venezolana, C.A. Wireless communications operator | Telefónica Hispanoamérica, S.A.                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 97.13%                                        
Telefónica Venezolana, C.A. Wireless communications operator | Comtel Comunicaciones Telefónicas, S.A.                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 2.87%                                        
Telefónica Colombia                                          
Disclosure of subsidiaries [line items]                                          
Equity | $       $ 3,410                                  
Proportion of ownership interest (as a percent) 67.50%                                        
Operaciones Tecnológicas y Comerciales S.A.S Communications services operator                                          
Disclosure of subsidiaries [line items]                                          
Equity | $       3,330                                  
Proportion of ownership interest (as a percent) 67.50%                                        
Pegaso Pcs S.A. de C.V. Communications services operator                                          
Disclosure of subsidiaries [line items]                                          
Equity | $         $ 2,041                                
Proportion of ownership interest (as a percent) 100.00%                                        
Pegaso Pcs S.A. de C.V. Communications services operator | Telefónica Hispanoamérica, S.A.                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 99.98%                                        
Pegaso Pcs S.A. de C.V. Communications services operator | Celular de Telefonía S.A. de CV.                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 0.02%                                        
Terra Networks México, S.A. de C.V. ISP, portal and real-time financial information services                                          
Disclosure of subsidiaries [line items]                                          
Equity | $         305                                
Proportion of ownership interest (as a percent) 100.00%                                        
Fisatel México, S.A. de C.V. SOFOM E.N.R. Integrated cash mangement, consulting and financial support for Group companies                                          
Disclosure of subsidiaries [line items]                                          
Equity | $         3,505                                
Proportion of ownership interest (as a percent) 100.00%                                        
Fisatel México, S.A. de C.V. SOFOM E.N.R. Integrated cash mangement, consulting and financial support for Group companies | Telefónica Hispanoamérica, S.A.                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 99.99%                                        
Fisatel México, S.A. de C.V. SOFOM E.N.R. Integrated cash mangement, consulting and financial support for Group companies | Pegaso Pcs S.A. de C.V. Communications services operator                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 0.01%                                        
Otecel, S.A. Wireless communications services provider                                          
Disclosure of subsidiaries [line items]                                          
Equity | $           $ 183                              
Proportion of ownership interest (as a percent) 100.00%                                        
Telefónica de Argentina, S.A. Telecommunications service provider                                          
Disclosure of subsidiaries [line items]                                          
Equity | $             $ 679,830                            
Proportion of ownership interest (as a percent) 100.00%                                        
Telefónica de Argentina, S.A. Telecommunications service provider | Telefónica Móviles Argentina, S.A.                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 79.06%                                        
Telefónica de Argentina, S.A. Telecommunications service provider | TLH Holdco, S.L.U. Sociedad holding                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 20.94%                                        
Telefónica Móviles Argentina, S.A. Telecommunications service provider                                          
Disclosure of subsidiaries [line items]                                          
Equity | $             84,706                            
Proportion of ownership interest (as a percent) 100.00%                                        
Telefónica Móviles Chile, S.A. Wireless communications services operator                                          
Disclosure of subsidiaries [line items]                                          
Equity | $               $ 1,631,069                          
Proportion of ownership interest (as a percent) 100.00%                                        
Telefónica Móviles Chile, S.A. Wireless communications services operator | Telefónica Hispanoamérica, S.A.                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 0.86%                                        
Telefónica Móviles Chile, S.A. Wireless communications services operator | Inversiones Telefónica Internacional Holding SpA.                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 99.14%                                        
Telefónica Chile, S.A. Local and international long distance telephony services provider                                          
Disclosure of subsidiaries [line items]                                          
Equity | $               874,772                          
Proportion of ownership interest (as a percent) 99.39%                                        
Telefónica Chile Holdings, S.L.U. Holding Company                                          
Disclosure of subsidiaries [line items]                                          
Equity | $               0                          
Proportion of ownership interest (as a percent) 100.00%                                        
Telefónica del Perú, S.A.A. Local, domestic and international long distance telephone service provider                                          
Disclosure of subsidiaries [line items]                                          
Equity | S/                 S/ 2,638                        
Proportion of ownership interest (as a percent) 99.15%                                        
Media Networks Latin America, S.A.C Telecommunications research activities and proyects                                          
Disclosure of subsidiaries [line items]                                          
Equity | S/                 158                        
Proportion of ownership interest (as a percent) 100.00%                                        
Telefónica Móviles del Uruguay, S.A. Wireless communications and services operator                                          
Disclosure of subsidiaries [line items]                                          
Equity | $                   $ 1,107                      
Proportion of ownership interest (as a percent) 100.00%                                        
Telefónica Infra, S.L.U. Sociedad holding                                          
Disclosure of subsidiaries [line items]                                          
Equity € 12                                        
Proportion of ownership interest (as a percent) 100.00%                                        
Telefónica Infra Germany GmbH Broadband telecommunications operator                                          
Disclosure of subsidiaries [line items]                                          
Equity € 0                                        
Proportion of ownership interest (as a percent) 100.00%                                        
Telefónica O2 Holdings Ltd. Holding company                                          
Disclosure of subsidiaries [line items]                                          
Equity | £                     £ 9                    
Proportion of ownership interest (as a percent) 100.00%                                        
Telefónica O2 Holdings Ltd. Holding company | Telefónica, S.A.                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 99.99%                                        
Telefónica O2 Holdings Ltd. Holding company | Telefónica Capital S.A.                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 0.01%                                        
MmO2 Ltd. Holding company                                          
Disclosure of subsidiaries [line items]                                          
Equity | £                     0                    
Proportion of ownership interest (as a percent) 100.00%                                        
O2 International Holdings Ltd. Holding company                                          
Disclosure of subsidiaries [line items]                                          
Equity | £                     0                    
Proportion of ownership interest (as a percent) 100.00%                                        
Telefónica Germany Holdings Ltd. Holding company                                          
Disclosure of subsidiaries [line items]                                          
Equity € 3,463                                        
Proportion of ownership interest (as a percent) 100.00%                                        
O2 (Europe) Ltd. Holding company                                          
Disclosure of subsidiaries [line items]                                          
Equity € 6,895                                        
Proportion of ownership interest (as a percent) 100.00%                                        
Telefónica International Holding, B.V Holding company                                          
Disclosure of subsidiaries [line items]                                          
Equity € 0                                        
Proportion of ownership interest (as a percent) 100.00%                                        
Telefónica Latinoamérica Holding, S.L.U. Sociedad holding                                          
Disclosure of subsidiaries [line items]                                          
Equity € 291                                        
Proportion of ownership interest (as a percent) 100.00%                                        
Telefónica Global Solutions, S.L.U. International service provider                                          
Disclosure of subsidiaries [line items]                                          
Equity € 1                                        
Proportion of ownership interest (as a percent) 100.00%                                        
Telefonica Global Solutions USA, Inc. Provision of telecommunications services                                          
Disclosure of subsidiaries [line items]                                          
Equity | $           202                              
Proportion of ownership interest (as a percent) 100.00%                                        
Telefónica Global Solutions Germany GmbH. International service provider                                          
Disclosure of subsidiaries [line items]                                          
Equity € 0                                        
Proportion of ownership interest (as a percent) 100.00%                                        
Telefónica Global Solutions México, S.A. de C.V. Carrying out research activities and projects in the field of telecommunications                                          
Disclosure of subsidiaries [line items]                                          
Equity | $         38                                
Proportion of ownership interest (as a percent) 100.00%                                        
Telefónica Innovación Digital, S.L.U. Desarrollo de actividades y servicios en el área de telecomunicaciones. Sociedad de cartera                                          
Disclosure of subsidiaries [line items]                                          
Equity € 28                                        
Proportion of ownership interest (as a percent) 100.00%                                        
Telefónica Digital Ltd. Developer Telco Services                                          
Disclosure of subsidiaries [line items]                                          
Equity | £                     45                    
Proportion of ownership interest (as a percent) 100.00%                                        
Telefonica Open Innovation S.L.U. Talent identification and development in ICT.                                          
Disclosure of subsidiaries [line items]                                          
Equity € 2                                        
Proportion of ownership interest (as a percent) 100.00%                                        
Wayra Chile Tecnología e Innovación SpA Technological innovation based business project development                                          
Disclosure of subsidiaries [line items]                                          
Equity | $               29,899                          
Proportion of ownership interest (as a percent) 100.00%                                        
Wayra Brasil Desenvolvedora e Apoiadora de Projetos Ltda Technological innovation based business project development                                          
Disclosure of subsidiaries [line items]                                          
Equity | R$   52                                      
Proportion of ownership interest (as a percent) 100.00%                                        
Wayra Brasil Desenvolvedora e Apoiadora de Projetos Ltda Technological innovation based business project development | Telefonica Open Innovation S.L.U. Talent identification and development in ICT.                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 99.99%                                        
Wayra Brasil Desenvolvedora e Apoiadora de Projetos Ltda Technological innovation based business project development | Telefónica Innovación Digital, S.L.U. Desarrollo de actividades y servicios en el área de telecomunicaciones. Sociedad de cartera                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 0.01%                                        
WY Telecom, S.A. de C.V. Talent identification and development in ICT                                          
Disclosure of subsidiaries [line items]                                          
Equity | $         134                                
Proportion of ownership interest (as a percent) 100.00%                                        
WY Telecom, S.A. de C.V. Talent identification and development in ICT | Telefonica Open Innovation S.L.U. Talent identification and development in ICT.                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 99.99%                                        
WY Telecom, S.A. de C.V. Talent identification and development in ICT | Telefónica Innovación Digital, S.L.U. Desarrollo de actividades y servicios en el área de telecomunicaciones. Sociedad de cartera                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 0.01%                                        
Wayra Argentina, S.A. Talent identification and development in ICT                                          
Disclosure of subsidiaries [line items]                                          
Equity | $             3,500                            
Proportion of ownership interest (as a percent) 100.00%                                        
Wayra Argentina, S.A. Talent identification and development in ICT | Telefónica, S.A.                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 5.00%                                        
Wayra Argentina, S.A. Talent identification and development in ICT | Telefonica Open Innovation S.L.U. Talent identification and development in ICT.                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 95.00%                                        
Wayra Colombia, S.A.S. Technological innovation based business project development                                          
Disclosure of subsidiaries [line items]                                          
Equity | $       2,304                                  
Proportion of ownership interest (as a percent) 100.00%                                        
Proyecto Wayra, C.A. Commercial, industrial and mercantile activities                                          
Disclosure of subsidiaries [line items]                                          
Equity | VEF     VEF 9                                    
Proportion of ownership interest (as a percent) 100.00%                                        
Wayra Perú Aceleradora de Proyectos, S.A.C. Technological innovation based business project development                                          
Disclosure of subsidiaries [line items]                                          
Equity | S/                 28                        
Proportion of ownership interest (as a percent) 100.00%                                        
Wayra UK Ltd. Technological innovation based business project development                                          
Disclosure of subsidiaries [line items]                                          
Equity | £                     0                    
Proportion of ownership interest (as a percent) 100.00%                                        
Terra Networks Peru S.A.                                          
Disclosure of subsidiaries [line items]                                          
Equity | S/                 10                        
Proportion of ownership interest (as a percent) 100.00%                                        
Terra Networks Argentina S.A.                                          
Disclosure of subsidiaries [line items]                                          
Equity | $             $ 132                            
Proportion of ownership interest (as a percent) 100.00%                                        
Terra Networks Argentina S.A. | Telefónica Latinoamérica Holding, S.L.                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 99.99%                                        
Terra Networks Argentina S.A. | Telefónica International Holding, B.V.                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 0.01%                                        
Telfisa Global                                          
Disclosure of subsidiaries [line items]                                          
Equity € 0                                        
Proportion of ownership interest (as a percent) 100.00%                                        
Telefonica Global Activities                                          
Disclosure of subsidiaries [line items]                                          
Equity € 0                                        
Proportion of ownership interest (as a percent) 100.00%                                        
Telefonica Global Services                                          
Disclosure of subsidiaries [line items]                                          
Equity € 0                                        
Proportion of ownership interest (as a percent) 100.00%                                        
Telefonica Global Roaming                                          
Disclosure of subsidiaries [line items]                                          
Equity € 0                                        
Proportion of ownership interest (as a percent) 100.00%                                        
Group 3G UMTS Holding                                          
Disclosure of subsidiaries [line items]                                          
Equity € 250                                        
Proportion of ownership interest (as a percent) 100.00%                                        
Telefonica Compras Electronicas                                          
Disclosure of subsidiaries [line items]                                          
Equity € 0                                        
Proportion of ownership interest (as a percent) 100.00%                                        
Telefonica Iot & Big Data Tech S.A.                                          
Disclosure of subsidiaries [line items]                                          
Equity € 1                                        
Proportion of ownership interest (as a percent) 100.00%                                        
Geprom Software Engineering S.L.                                          
Disclosure of subsidiaries [line items]                                          
Equity € 0                                        
Proportion of ownership interest (as a percent) 100.00%                                        
Geprom Software Engineering S.A.                                          
Disclosure of subsidiaries [line items]                                          
Equity | $         0                                
Proportion of ownership interest (as a percent) 100.00%                                        
TIS Hispanoamerica, S.L.                                          
Disclosure of subsidiaries [line items]                                          
Equity € 0                                        
Proportion of ownership interest (as a percent) 100.00%                                        
Telefonica Capital                                          
Disclosure of subsidiaries [line items]                                          
Equity € 7                                        
Proportion of ownership interest (as a percent) 100.00%                                        
Lotca Servicios Integrales                                          
Disclosure of subsidiaries [line items]                                          
Equity € 17                                        
Proportion of ownership interest (as a percent) 100.00%                                        
Fonditel Pensiones, Entidad Gestora de Fondos de Pensiones                                          
Disclosure of subsidiaries [line items]                                          
Equity € 16                                        
Proportion of ownership interest (as a percent) 70.00%                                        
Fonditel Gestion, Soc. Gestora de Instituciones de Inversion Colectiva                                          
Disclosure of subsidiaries [line items]                                          
Equity € 2                                        
Proportion of ownership interest (as a percent) 100.00%                                        
Telefonica Luxembourg Holding                                          
Disclosure of subsidiaries [line items]                                          
Equity € 3                                        
Proportion of ownership interest (as a percent) 100.00%                                        
Nova Casiopea RE                                          
Disclosure of subsidiaries [line items]                                          
Equity € 15                                        
Proportion of ownership interest (as a percent) 100.00%                                        
Telefonica Seguros y Reaseguros Compañia Aseguradora                                          
Disclosure of subsidiaries [line items]                                          
Equity € 24                                        
Proportion of ownership interest (as a percent) 100.00%                                        
Telefonica Finanzas S.A.U.                                          
Disclosure of subsidiaries [line items]                                          
Equity € 3                                        
Proportion of ownership interest (as a percent) 100.00%                                        
Telefonica Correduria de Seguros y Reaseguros Compañia de Mediacion                                          
Disclosure of subsidiaries [line items]                                          
Equity € 0                                        
Proportion of ownership interest (as a percent) 100.00%                                        
Telefonica Correduria de Seguros y Reaseguros Compañia de Mediacion | Telefónica, S.A.                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 16.67%                                        
Telefonica Correduria de Seguros y Reaseguros Compañia de Mediacion | Telefónica Finanzas, S.A.U. (TELFISA)                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 83.33%                                        
Telefonica Europe, B.V.                                          
Disclosure of subsidiaries [line items]                                          
Equity € 0                                        
Proportion of ownership interest (as a percent) 100.00%                                        
Telefónica Participaciones, S.A.U. Financial debt instrument issuer                                          
Disclosure of subsidiaries [line items]                                          
Equity € 0                                        
Proportion of ownership interest (as a percent) 100.00%                                        
Telefonica Emisiones S.A.U.                                          
Disclosure of subsidiaries [line items]                                          
Equity € 0                                        
Proportion of ownership interest (as a percent) 100.00%                                        
Alianca Atlantica Holding B.V.                                          
Disclosure of subsidiaries [line items]                                          
Equity € 40                                        
Proportion of ownership interest (as a percent) 87.65%                                        
Alianca Atlantica Holding B.V. | Telefónica, S.A.                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 50.00%                                        
Alianca Atlantica Holding B.V. | Telefônica Brasil, S.A.                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 37.65%                                        
Telefónica Serviços Empresariais do BRASIL, Ltda.                                          
Disclosure of subsidiaries [line items]                                          
Equity | R$   63                                      
Proportion of ownership interest (as a percent) 100.00%                                        
Telefónica Gestión Integral de Edificios y Servicios S.L.                                          
Disclosure of subsidiaries [line items]                                          
Equity € 0                                        
Proportion of ownership interest (as a percent) 100.00%                                        
O2 Worldwide Limited                                          
Disclosure of subsidiaries [line items]                                          
Equity | £                     0                    
Proportion of ownership interest (as a percent) 100.00%                                        
Telefonica Servicios Globales S.L.                                          
Disclosure of subsidiaries [line items]                                          
Equity € 1                                        
Proportion of ownership interest (as a percent) 100.00%                                        
Telefonica Holding Atticus, B.V.                                          
Disclosure of subsidiaries [line items]                                          
Equity € 0                                        
Proportion of ownership interest (as a percent) 100.00%                                        
Telefónica Soluciones de Criptografía, S.A.                                          
Disclosure of subsidiaries [line items]                                          
Equity € 1                                        
Proportion of ownership interest (as a percent) 100.00%                                        
Cryptography & Security Systems S.L.U.                                          
Disclosure of subsidiaries [line items]                                          
Equity € 0                                        
Proportion of ownership interest (as a percent) 100.00%                                        
Telefónica Centroamérica Inversiones ,S.L.                                          
Disclosure of subsidiaries [line items]                                          
Equity € 1                                        
Proportion of ownership interest (as a percent) 60.00%                                        
Telefónica Tech S.L.                                          
Disclosure of subsidiaries [line items]                                          
Equity € 67                                        
Proportion of ownership interest (as a percent) 100.00%                                        
Telefónica Cybersecurity & Cloud Tech SL.                                          
Disclosure of subsidiaries [line items]                                          
Equity € 34                                        
Proportion of ownership interest (as a percent) 100.00%                                        
Telefónica Cybersecurity & Cloud Tech Chile SpA.                                          
Disclosure of subsidiaries [line items]                                          
Equity | $               20,540                          
Proportion of ownership interest (as a percent) 100.00%                                        
Telefónica Tech Inc.                                          
Disclosure of subsidiaries [line items]                                          
Equity | $           7                              
Proportion of ownership interest (as a percent) 100.00%                                        
Audertis Audit Services S.L.                                          
Disclosure of subsidiaries [line items]                                          
Equity € 0                                        
Proportion of ownership interest (as a percent) 100.00%                                        
Govertis Advisory Services S.L.                                          
Disclosure of subsidiaries [line items]                                          
Equity € 0                                        
Proportion of ownership interest (as a percent) 100.00%                                        
Telefonica Cybersecurity Tech Colombia S.A.S.                                          
Disclosure of subsidiaries [line items]                                          
Equity | $       406                                  
Proportion of ownership interest (as a percent) 100.00%                                        
Telefonica Cybersecurity Tech Mexico, S.A de C.V.                                          
Disclosure of subsidiaries [line items]                                          
Equity | $         48                                
Proportion of ownership interest (as a percent) 100.00%                                        
Telefônica Cibersegurança e Tecnología do Brasil Ltda                                          
Disclosure of subsidiaries [line items]                                          
Equity | R$   26                                      
Proportion of ownership interest (as a percent) 100.00%                                        
Telefónica Cybersecurity & Cloud Tech Perú S.A.C                                          
Disclosure of subsidiaries [line items]                                          
Equity | S/                 30                        
Proportion of ownership interest (as a percent) 100.00%                                        
Telefonica Cybersecurity Tech Ecuador Tctech S.A.                                          
Disclosure of subsidiaries [line items]                                          
Equity | $           0                              
Proportion of ownership interest (as a percent) 100.00%                                        
Telefonica Cybersecurity Tech Ecuador Tctech S.A. | Otecel, S.A.                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 99.00%                                        
Telefonica Cybersecurity Tech Ecuador Tctech S.A. | Telefonica Global Solutions Ecuador TGSE, S.A.                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 1.00%                                        
Telefonica Cybersecurity & Cloud Tech Deutschland GmbH                                          
Disclosure of subsidiaries [line items]                                          
Equity € 0                                        
Proportion of ownership interest (as a percent) 100.00%                                        
Acens Technologies                                          
Disclosure of subsidiaries [line items]                                          
Equity € 2                                        
Proportion of ownership interest (as a percent) 100.00%                                        
Altostratus Solutions, S.L.                                          
Disclosure of subsidiaries [line items]                                          
Equity € 0                                        
Proportion of ownership interest (as a percent) 100.00%                                        
Telefonica Tech UK & Ireland, Limited                                          
Disclosure of subsidiaries [line items]                                          
Equity | £                     14                    
Proportion of ownership interest (as a percent) 100.00%                                        
Telefonica Tech UK Holdings Limited                                          
Disclosure of subsidiaries [line items]                                          
Equity | £                     0                    
Proportion of ownership interest (as a percent) 100.00%                                        
Telefonica Tech UK TOG Limited                                          
Disclosure of subsidiaries [line items]                                          
Equity | £                     0                    
Proportion of ownership interest (as a percent) 100.00%                                        
Telefonica Tech UK Managed Services Limited                                          
Disclosure of subsidiaries [line items]                                          
Equity | £                     0                    
Proportion of ownership interest (as a percent) 100.00%                                        
Telefonica Tech UK Limited                                          
Disclosure of subsidiaries [line items]                                          
Equity | £                     0                    
Proportion of ownership interest (as a percent) 100.00%                                        
Telefonica Tech Northern Ireland Holdings Limited                                          
Disclosure of subsidiaries [line items]                                          
Equity | £                     0                    
Proportion of ownership interest (as a percent) 100.00%                                        
Telefonica Tech Communication & Collaboration Limited                                          
Disclosure of subsidiaries [line items]                                          
Equity | £                     0                    
Proportion of ownership interest (as a percent) 100.00%                                        
Telefonica Tech Northern Ireland Limited                                          
Disclosure of subsidiaries [line items]                                          
Equity | £                     0                    
Proportion of ownership interest (as a percent) 100.00%                                        
Telefonica Tech Ireland Limited                                          
Disclosure of subsidiaries [line items]                                          
Equity € 0                                        
Proportion of ownership interest (as a percent) 100.00%                                        
Telefonica Tech Ocean Limited                                          
Disclosure of subsidiaries [line items]                                          
Equity | £                     0                    
Proportion of ownership interest (as a percent) 100.00%                                        
Perpetual Topco Limited                                          
Disclosure of subsidiaries [line items]                                          
Equity | £                     4                    
Proportion of ownership interest (as a percent) 100.00%                                        
Perpetual Midco Limited                                          
Disclosure of subsidiaries [line items]                                          
Equity | £                     4                    
Proportion of ownership interest (as a percent) 100.00%                                        
Perpetual Bidco Limited                                          
Disclosure of subsidiaries [line items]                                          
Equity | £                     3                    
Proportion of ownership interest (as a percent) 100.00%                                        
Incremental Group Holdings Limited                                          
Disclosure of subsidiaries [line items]                                          
Equity | £                     1                    
Proportion of ownership interest (as a percent) 100.00%                                        
Redspire Limited                                          
Disclosure of subsidiaries [line items]                                          
Equity | £                     0                    
Proportion of ownership interest (as a percent) 100.00%                                        
Incremental Group Limited                                          
Disclosure of subsidiaries [line items]                                          
Equity | £                     0                    
Proportion of ownership interest (as a percent) 100.00%                                        
Adatis Group Limited                                          
Disclosure of subsidiaries [line items]                                          
Equity | £                     0                    
Proportion of ownership interest (as a percent) 100.00%                                        
Adatis Consulting Limited                                          
Disclosure of subsidiaries [line items]                                          
Equity | £                     0                    
Proportion of ownership interest (as a percent) 100.00%                                        
Adatis BG LTD                                          
Disclosure of subsidiaries [line items]                                          
Equity | лв                       лв 0                  
Proportion of ownership interest (as a percent) 100.00%                                        
Adatis India Private Limited                                          
Disclosure of subsidiaries [line items]                                          
Equity | ₨                         ₨ 0                
Proportion of ownership interest (as a percent) 100.00%                                        
Adatis India Private Limited | Adatis Group Limited                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 99.00%                                        
Adatis India Private Limited | Adatis Consulting Limited                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 1.00%                                        
Adatis Managed Services Limited                                          
Disclosure of subsidiaries [line items]                                          
Equity | £                     0                    
Proportion of ownership interest (as a percent) 100.00%                                        
BE-terna Acceleration Holding GmbH                                          
Disclosure of subsidiaries [line items]                                          
Equity € 0                                        
Proportion of ownership interest (as a percent) 100.00%                                        
BE-terna Acceleration GmbH                                          
Disclosure of subsidiaries [line items]                                          
Equity € 0                                        
Proportion of ownership interest (as a percent) 100.00%                                        
BE-terna Enhancement GmbH                                          
Disclosure of subsidiaries [line items]                                          
Equity € 0                                        
Proportion of ownership interest (as a percent) 100.00%                                        
BE-terna Germany GmbH                                          
Disclosure of subsidiaries [line items]                                          
Equity € 0                                        
Proportion of ownership interest (as a percent) 100.00%                                        
BE-terna AB (Sweden)                                          
Disclosure of subsidiaries [line items]                                          
Equity | kr                           kr 0              
Proportion of ownership interest (as a percent) 100.00%                                        
BE-Terna Automation AG                                          
Disclosure of subsidiaries [line items]                                          
Equity | SFr                             SFr 0            
Proportion of ownership interest (as a percent) 100.00%                                        
BE-terna ApS (Denmark)                                          
Disclosure of subsidiaries [line items]                                          
Equity | kr                               kr 0          
Proportion of ownership interest (as a percent) 100.00%                                        
BE-terna B.V. (Netherlands)                                          
Disclosure of subsidiaries [line items]                                          
Equity € 0                                        
Proportion of ownership interest (as a percent) 100.00%                                        
BE-terna GmbH (Leipzig)                                          
Disclosure of subsidiaries [line items]                                          
Equity € 0                                        
Proportion of ownership interest (as a percent) 100.00%                                        
BE-terna Austria GmbH                                          
Disclosure of subsidiaries [line items]                                          
Equity € 0                                        
Proportion of ownership interest (as a percent) 100.00%                                        
BE-terna GmbH (Innsbruck)                                          
Disclosure of subsidiaries [line items]                                          
Equity € 0                                        
Proportion of ownership interest (as a percent) 100.00%                                        
Pipol A/S                                          
Disclosure of subsidiaries [line items]                                          
Equity | kr                               kr 1          
Proportion of ownership interest (as a percent) 100.00%                                        
BE-terna A/S (Norway)                                          
Disclosure of subsidiaries [line items]                                          
Equity | kr                                 kr 0        
Proportion of ownership interest (as a percent) 100.00%                                        
BE-terna Business Solutions GmbH                                          
Disclosure of subsidiaries [line items]                                          
Equity € 0                                        
Proportion of ownership interest (as a percent) 100.00%                                        
BE-terna Industry Solutions GmbH                                          
Disclosure of subsidiaries [line items]                                          
Equity € 0                                        
Proportion of ownership interest (as a percent) 100.00%                                        
BE-terna AG (Switzerland)                                          
Disclosure of subsidiaries [line items]                                          
Equity | SFr                             SFr 0            
Proportion of ownership interest (as a percent) 100.00%                                        
BE-terna SRL                                          
Disclosure of subsidiaries [line items]                                          
Equity € 0                                        
Proportion of ownership interest (as a percent) 100.00%                                        
BE-terna Adriatic                                          
Disclosure of subsidiaries [line items]                                          
Equity € 0                                        
Proportion of ownership interest (as a percent) 100.00%                                        
BE-terna Belgrade (Serbia)                                          
Disclosure of subsidiaries [line items]                                          
Equity | дин                                   дин 13      
Proportion of ownership interest (as a percent) 100.00%                                        
BE-terna Ljubijana (Slovenia)                                          
Disclosure of subsidiaries [line items]                                          
Equity € 0                                        
Proportion of ownership interest (as a percent) 100.00%                                        
BE-terna Zagreb (Croatia)                                          
Disclosure of subsidiaries [line items]                                          
Equity € 2                                        
Proportion of ownership interest (as a percent) 100.00%                                        
Telxius Telecom, S.A.                                          
Disclosure of subsidiaries [line items]                                          
Equity € 260                                        
Proportion of ownership interest (as a percent) 70.00%                                        
Telxius Cable América, S.A.                                          
Disclosure of subsidiaries [line items]                                          
Equity | $           291                              
Proportion of ownership interest (as a percent) 70.00%                                        
Telxius Cable España, S.L.U.                                          
Disclosure of subsidiaries [line items]                                          
Equity € 5                                        
Proportion of ownership interest (as a percent) 70.00%                                        
Telxius Cable República Dominicana, S.A.S.                                          
Disclosure of subsidiaries [line items]                                          
Equity | $           6                              
Proportion of ownership interest (as a percent) 70.00%                                        
Telxius Cable República Dominicana, S.A.S. | Telxius Cable América, S.A.                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 69.30%                                        
Telxius Cable República Dominicana, S.A.S. | Telxius Cable España, S.L.U.                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 0.70%                                        
Telxius Cable Argentina, S.A.                                          
Disclosure of subsidiaries [line items]                                          
Equity | $           78                              
Proportion of ownership interest (as a percent) 70.00%                                        
Telxius Cable Argentina, S.A. | Telxius Cable América, S.A.                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 66.50%                                        
Telxius Cable Argentina, S.A. | Telxius Cable España, S.L.U.                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 3.50%                                        
Telxius Cable Panamá, S.A. Installation and operation of telecommunications networks for wholesalers                                          
Disclosure of subsidiaries [line items]                                          
Equity | $           10                              
Proportion of ownership interest (as a percent) 70.00%                                        
Telxius Cable Puerto Rico, Inc. High capacity optical fibre network communications services                                          
Disclosure of subsidiaries [line items]                                          
Equity | $           14                              
Proportion of ownership interest (as a percent) 70.00%                                        
Telxius Cable USA, Inc. High bandwidth communications services                                          
Disclosure of subsidiaries [line items]                                          
Equity | $           58                              
Proportion of ownership interest (as a percent) 70.00%                                        
Telxius Cable Ecuador, S.A. Sale of usage of data transmission capacity via an underwater optical fibre network                                          
Disclosure of subsidiaries [line items]                                          
Equity | $           5                              
Proportion of ownership interest (as a percent) 70.00%                                        
Telxius Cable Chile S.A.                                          
Disclosure of subsidiaries [line items]                                          
Equity | $           26                              
Proportion of ownership interest (as a percent) 70.00%                                        
Telxius Cable Guatemala, S.A.                                          
Disclosure of subsidiaries [line items]                                          
Equity | $           20                              
Proportion of ownership interest (as a percent) 70.00%                                        
Telxius Cable Perú, S.A.C.                                          
Disclosure of subsidiaries [line items]                                          
Equity | $           20                              
Proportion of ownership interest (as a percent) 70.00%                                        
Telxius Cable Colombia, S.A. Supply of data transmission capacity via underwater cable system                                          
Disclosure of subsidiaries [line items]                                          
Equity | $           4                              
Proportion of ownership interest (as a percent) 70.00%                                        
Telxius Cable Colombia, S.A. Supply of data transmission capacity via underwater cable system | Telxius Cable América, S.A.                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 66.49%                                        
Telxius Cable Colombia, S.A. Supply of data transmission capacity via underwater cable system | Telxius Cable Chile S.A.                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 1.17%                                        
Telxius Cable Colombia, S.A. Supply of data transmission capacity via underwater cable system | Telxius Cable Perú, S.A.C.                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 1.17%                                        
Telxius Cable Colombia, S.A. Supply of data transmission capacity via underwater cable system | Telxius Cable Guatemala, S.A.                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 1.16%                                        
Telxius Cable Colombia, S.A. Supply of data transmission capacity via underwater cable system | Telxius Cable Argentina, S.A.                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 0.01%                                        
Telxius Cable Brasil Participaçoes, Ltda. Holding company                                          
Disclosure of subsidiaries [line items]                                          
Equity | $           62                              
Proportion of ownership interest (as a percent) 70.00%                                        
Telxius Cable Brasil, Ltda. Operation and deployment of telecommunications infrastructure                                          
Disclosure of subsidiaries [line items]                                          
Equity | $           74                              
Proportion of ownership interest (as a percent) 70.00%                                        
Telxius Cable Bolivia, S.A. Establishment and operation of any kind of communications infrastructure and/or network                                          
Disclosure of subsidiaries [line items]                                          
Equity | $           2                              
Proportion of ownership interest (as a percent) 70.00%                                        
Telxius Cable Bolivia, S.A. Establishment and operation of any kind of communications infrastructure and/or network | Telxius Cable América, S.A.                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 68.60%                                        
Telxius Cable Bolivia, S.A. Establishment and operation of any kind of communications infrastructure and/or network | Telxius Cable España, S.L.U.                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 0.70%                                        
Telxius Cable Bolivia, S.A. Establishment and operation of any kind of communications infrastructure and/or network | Telxius Cable Argentina, S.A.                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 0.70%                                        
Telxius México, S.R.L. DE C.V                                          
Disclosure of subsidiaries [line items]                                          
Equity | $           0                              
Proportion of ownership interest (as a percent) 70.00%                                        
Telxius México, S.R.L. DE C.V | Telxius Cable América, S.A.                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 69.99%                                        
Telxius México, S.R.L. DE C.V | Telxius Cable España, S.L.U.                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 0.01%                                        
Telefónica Local Services GmbH Holding                                          
Disclosure of subsidiaries [line items]                                          
Equity € 0                                        
Proportion of ownership interest (as a percent) 100.00%                                        
VMO2                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 50.00%                                        
Investments accounted for by the equity method | £                     0                    
FiBrasil Infraestructura e Fibra Ótica, S.A.                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 43.82%                                        
Investments accounted for by the equity method | R$   189                                      
FiBrasil Infraestructura e Fibra Ótica, S.A. | Telefónica Infra, S.L.U. Sociedad holding                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 25.00%                                        
FiBrasil Infraestructura e Fibra Ótica, S.A. | Telefonica Brasil, S.A.                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 18.82%                                        
VivaE Educação Digital S.A                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 37.65%                                        
Investments accounted for by the equity method | R$   26                                      
HoldCo infraCo SpA                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 39.76%                                        
Investments accounted for by the equity method | $               135,534                          
InfraCo, SpA                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 39.76%                                        
Investments accounted for by the equity method | $               246,002                          
Telefónica Factoring España, S.A. Factoring                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 50.00%                                        
Investments accounted for by the equity method € 5                                        
Telefónica Factoring Do Brasil, Ltd. Factoring services provider                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 50.00%                                        
Investments accounted for by the equity method | R$   R$ 5                                      
Telefónica Factoring Do Brasil, Ltd. Factoring services provider | Telefónica, S.A.                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 40.00%                                        
Telefónica Factoring Do Brasil, Ltd. Factoring services provider | Telefónica Factoring España, S.A. Factoring                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 10.00%                                        
Telefónica Factoring Mexico, S.A. de C.V. SOFOM ENR Factoring services provider                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 50.00%                                        
Investments accounted for by the equity method | $         $ 34                                
Telefónica Factoring Mexico, S.A. de C.V. SOFOM ENR Factoring services provider | Telefónica, S.A.                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 40.50%                                        
Telefónica Factoring Mexico, S.A. de C.V. SOFOM ENR Factoring services provider | Telefónica Factoring España, S.A. Factoring                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 9.50%                                        
Telefónica Factoring Perú, S.A.C. Factoring services provider                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 50.00%                                        
Investments accounted for by the equity method | S/                 6                        
Telefónica Factoring Perú, S.A.C. Factoring services provider | Telefónica, S.A.                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 40.50%                                        
Telefónica Factoring Perú, S.A.C. Factoring services provider | Telefónica Factoring España, S.A. Factoring                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 9.50%                                        
Telefónica Factoring Colombia, S.A. Factoring services provider                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 50.00%                                        
Investments accounted for by the equity method | $       4,000                                  
Telefónica Factoring Colombia, S.A. Factoring services provider | Telefónica, S.A.                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 40.50%                                        
Telefónica Factoring Colombia, S.A. Factoring services provider | Telefónica Factoring España, S.A. Factoring                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 9.50%                                        
Telefónica Factoring Chile, SpA. Factoring services provider                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 50.00%                                        
Investments accounted for by the equity method | $               $ 547                          
Mobile Financial Services Holding SPRL Financial services                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 50.00%                                        
Investments accounted for by the equity method | $           $ 198                              
Mobile Financial Services Holding SPRL Financial services | Telefonica Internacional Holding, B.V                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 26.28%                                        
Mobile Financial Services Holding SPRL Financial services | Telefonica Holding Atticus, B.V                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 23.72%                                        
Telefónica Consumer Finance, Establecimiento Financiero de Crédito, S.A. Specialised credit institution                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 50.00%                                        
Investments accounted for by the equity method € 5                                        
Movistar Consumer Finance Colombia SAS.                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 50.00%                                        
Investments accounted for by the equity method | $       6,000                                  
Alamo HoldCo S.L.                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 27.00%                                        
Investments accounted for by the equity method € 0                                        
Onnet Fibra Colombia S.A.S.                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 27.00%                                        
Investments accounted for by the equity method | $       $ 56,307                                  
Internet para todos, S.A.C.                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 54.21%                                        
Investments accounted for by the equity method | S/                 S/ 364                        
Movistar Prosegur Alarmas                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 50.00%                                        
Investments accounted for by the equity method € 0                                        
Prosegur Soluciones S.A.U.                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 50.00%                                        
Investments accounted for by the equity method € 0                                        
Buendía Estudios, S.L. Service provision related to film and video production activities                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 50.00%                                        
Investments accounted for by the equity method € 0                                        
Buendia Estudios Uno, S.L.U.                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 50.00%                                        
Investments accounted for by the equity method € 0                                        
Buendia Estudios Dos, S.L.U.                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 50.00%                                        
Investments accounted for by the equity method € 0                                        
Buendía Estudios Canarias S.L.U.                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 50.00%                                        
Investments accounted for by the equity method € 0                                        
Buendia Estudios Bizkaia, S.L.                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 50.00%                                        
Investments accounted for by the equity method € 0                                        
Solar360 de Repsol y Movistar S.L.                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 50.00%                                        
Investments accounted for by the equity method € 0                                        
UGG TopCo/HoldCo General Partner GmbH.                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 48.24%                                        
Investments accounted for by the equity method € 0                                        
UGG TopCo/HoldCo General Partner GmbH. | Telefónica Deutschland Holding A.G.                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 8.24%                                        
UGG TopCo/HoldCo General Partner GmbH. | Telefónica Infra Germany GmbH Broadband telecommunications operator                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 40.00%                                        
UGG TopCo GmbH & Co KG                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 48.24%                                        
Investments accounted for by the equity method € 0                                        
UGG TopCo GmbH & Co KG | Telefónica Deutschland Holding A.G.                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 8.24%                                        
UGG TopCo GmbH & Co KG | Telefónica Infra Germany GmbH Broadband telecommunications operator                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 40.00%                                        
UGG HoldCo GmbH& Co KG                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 48.24%                                        
Investments accounted for by the equity method € 0                                        
UGG General Partner GmbH                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 48.24%                                        
Investments accounted for by the equity method € 0                                        
Unsere Grüne Glasfaser                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 48.24%                                        
Investments accounted for by the equity method € 0                                        
Daytona Midco SL.                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 20.00%                                        
Investments accounted for by the equity method € 0                                        
Digital Data Centre BidCo, SLU.                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 20.00%                                        
Investments accounted for by the equity method € 4                                        
Telefonica Renting, S.A.                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 50.00%                                        
Investments accounted for by the equity method € 0                                        
Opal Holdco Limited                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 50.00%                                        
Investments accounted for by the equity method | £                     0                    
Opal Jvco Limited (nexfibre)                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 25.00%                                        
Investments accounted for by the equity method | £                     £ 0                    
Utiq, S.A.                                          
Disclosure of subsidiaries [line items]                                          
Proportion of ownership interest (as a percent) 25.00%                                        
Investments accounted for by the equity method € 14