v3.26.1
Note 17 Goodwill, breakdown by CGU and changes of the year (Details) - EUR (€)
€ in Millions
 6 Months Ended 12 Months Ended
Jun. 30, 2026
Dec. 31, 2025
Disclosure of reconciliation of changes in goodwill [line items]    
Goodwill at beginning of period € 715 € 700
Additional recognition, goodwill 0 0
Increase (decrease) through net exchange differences, goodwill 51 15
Impairment loss recognised in profit or loss, goodwill 0 0
Increase (decrease) through transfers and other changes, intangible assets and goodwill 0 0
Goodwill at end of period 767 715
MEXICO    
Disclosure of reconciliation of changes in goodwill [line items]    
Goodwill at beginning of period 553 541
Additional recognition, goodwill 0 0
Increase (decrease) through net exchange differences, goodwill 34 11
Impairment loss recognised in profit or loss, goodwill 0 0
Increase (decrease) through transfers and other changes, intangible assets and goodwill 0 0
Goodwill at end of period 586 553
COLOMBIA    
Disclosure of reconciliation of changes in goodwill [line items]    
Goodwill at beginning of period 137 132
Additional recognition, goodwill 0 0
Increase (decrease) through net exchange differences, goodwill 17 5
Impairment loss recognised in profit or loss, goodwill 0 0
Increase (decrease) through transfers and other changes, intangible assets and goodwill 0 0
Goodwill at end of period 154 137
CHILE    
Disclosure of reconciliation of changes in goodwill [line items]    
Goodwill at beginning of period 22 23
Additional recognition, goodwill 0 0
Increase (decrease) through net exchange differences, goodwill 0 (1)
Impairment loss recognised in profit or loss, goodwill 0 0
Increase (decrease) through transfers and other changes, intangible assets and goodwill 0 0
Goodwill at end of period 22 22
Other Countries [Member]    
Disclosure of reconciliation of changes in goodwill [line items]    
Goodwill at beginning of period 4 4
Additional recognition, goodwill 0 0
Increase (decrease) through net exchange differences, goodwill 0 0
Impairment loss recognised in profit or loss, goodwill 0 0
Increase (decrease) through transfers and other changes, intangible assets and goodwill 0 0
Goodwill at end of period € 4 € 4