v3.26.1
Tangible assets - Narrative (Details) - EUR (€)
€ in Millions
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Disclosure of detailed information about property, plant and equipment [line items]      
Property, plant and equipment € 26,416 € 31,212 € 32,926
Tangible assets 27,438 32,087 33,882
For own use      
Disclosure of detailed information about property, plant and equipment [line items]      
Tangible assets 11,663 12,636 13,408
For own use | Abroad      
Disclosure of detailed information about property, plant and equipment [line items]      
Property, plant and equipment 6,545 6,531 7,119
Leased out under an operating lease      
Disclosure of detailed information about property, plant and equipment [line items]      
Tangible assets 14,753 18,576 19,518
Leased out under an operating lease | Vehicles | Santander US Auto      
Disclosure of detailed information about property, plant and equipment [line items]      
Tangible assets 7,227 11,336 12,525
Investment property      
Disclosure of detailed information about property, plant and equipment [line items]      
Tangible assets 1,022 875 956
Fair value of investment property 1,194 1,041 1,163
Unrealized gains (losses) on fair value adjustment € 172 € 166 € 207