v3.26.1
Investments in Joint Ventures and Associates - Summarized Financial Information of Joint Ventures (Detail) - EUR (€)
€ in Millions
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Summarized statement of financial position        
Cash and cash equivalents € 2,733 € 3,469 € 4,074 € 8,486
Total assets 317,233 327,390    
Other current liabilities 6,281 6,930    
Other non-current liabilities 164 194    
Total liabilities 307,738 318,077    
Profit or loss 1,045 660 (391)  
Income tax (expense) or income (65) 16 209  
Post-tax profit or (loss) 980 676 (199)  
Other comprehensive income 412 573 421  
Total comprehensive income 1,392 1,248 € 222  
Santander Spain Life [member]        
Summarized statement of financial position        
Cash and cash equivalents 30 30    
Other current assets 57 63    
Total current assets 87 93    
Non-current assets 1,004 1,023    
Total assets 1,091 1,116    
Current financial liabilities excluding trade payables and other provisions 0 0    
Other current liabilities 231 53    
Current liabilities 231 53    
Non-current financial liabilities excluding trade payables and other provisions 0 0    
Other non-current liabilities 236 406    
Total non-current financial liabilities 236 406    
Total liabilities 467 459    
Net assets 624 657    
Revenue 381 340    
Depreciation and amortization (36) (34)    
Interest income 6 6    
Interest expense 0 0    
Profit or loss 101 95    
Income tax (expense) or income (25) (21)    
Post-tax profit or (loss) 76 74    
Other comprehensive income 3 4    
Total comprehensive income 79 78    
Dividends received 57 53    
AIFMC [member]        
Summarized statement of financial position        
Cash and cash equivalents 62 436    
Other current assets 764 744    
Total current assets 827 1,180    
Non-current assets 571 194    
Total assets 1,398 1,374    
Current financial liabilities excluding trade payables and other provisions 0 0    
Other current liabilities 374 350    
Current liabilities 374 350    
Non-current financial liabilities excluding trade payables and other provisions 0 0    
Other non-current liabilities 0 38    
Total non-current financial liabilities 0 38    
Total liabilities 374 388    
Net assets 1,024 985    
Revenue 488 415    
Depreciation and amortization (5) (6)    
Interest income 27 18    
Interest expense 0 0    
Profit or loss 257 280    
Income tax (expense) or income (71) (78)    
Post-tax profit or (loss) 186 202    
Other comprehensive income 0 0    
Total comprehensive income 186 202    
Dividends received 34 29    
Other Joint ventures [member]        
Summarized statement of financial position        
Cash and cash equivalents 66 72    
Other current assets 2,315 1,055    
Total current assets 2,381 1,127    
Non-current assets 5,718 7,429    
Total assets 8,099 8,556    
Current financial liabilities excluding trade payables and other provisions 3 4    
Other current liabilities 596 452    
Current liabilities 599 456    
Non-current financial liabilities excluding trade payables and other provisions 61 66    
Other non-current liabilities 6,160 6,874    
Total non-current financial liabilities 6,221 6,941    
Total liabilities 6,820 7,397    
Net assets 1,279 1,159    
Revenue 2,807 2,662    
Depreciation and amortization (29) (28)    
Interest income 166 128    
Interest expense (4) (9)    
Profit or loss 435 272    
Income tax (expense) or income (100) (80)    
Post-tax profit or (loss) 335 192    
Other comprehensive income 5 (134)    
Total comprehensive income 340 58    
Dividends received € 95 € 59