v3.26.1
Debt securities - Schedule of debt instruments by origin of issuer (Details) - EUR (€)
€ in Millions
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Debt Instruments      
Financial assets € 300,026 € 283,497 € 243,203
Financial assets (as a percent)   100.00% 100.00%
Debt securities      
Debt Instruments      
Financial assets € 300,026 € 283,497 € 243,203
Financial assets (as a percent) 100.00% 100.00% 100.00%
Private fixed income      
Debt Instruments      
Financial assets € 63,816 € 61,831 € 57,150
Public fixed income      
Debt Instruments      
Financial assets 236,210 221,666 186,053
Spain | Debt securities      
Debt Instruments      
Financial assets € 66,270 € 58,820 € 42,846
Financial assets (as a percent) 22.09% 20.75% 17.62%
Spain | Private fixed income      
Debt Instruments      
Financial assets € 2,528 € 1,901 € 2,525
Spain | Public fixed income      
Debt Instruments      
Financial assets 63,742 56,919 40,321
United Kingdom | Debt securities      
Debt Instruments      
Financial assets € 11,563 € 12,980 € 7,564
Financial assets (as a percent) 3.85% 4.58% 3.11%
United Kingdom | Private fixed income      
Debt Instruments      
Financial assets € 2,336 € 3,077 € 2,816
United Kingdom | Public fixed income      
Debt Instruments      
Financial assets 9,227 9,903 4,748
Portugal | Debt securities      
Debt Instruments      
Financial assets € 8,839 € 8,362 € 7,641
Financial assets (as a percent) 2.95% 2.95% 3.14%
Portugal | Private fixed income      
Debt Instruments      
Financial assets € 3,212 € 3,224 € 2,826
Portugal | Public fixed income      
Debt Instruments      
Financial assets 5,627 5,138 4,815
Italy | Debt securities      
Debt Instruments      
Financial assets € 27,036 € 26,026 € 15,913
Financial assets (as a percent) 9.01% 9.18% 6.54%
Italy | Private fixed income      
Debt Instruments      
Financial assets € 2,821 € 3,072 € 2,968
Italy | Public fixed income      
Debt Instruments      
Financial assets 24,215 22,954 12,945
Ireland | Debt securities      
Debt Instruments      
Financial assets € 4,281 € 4,571 € 5,643
Financial assets (as a percent) 1.43% 1.61% 2.32%
Ireland | Private fixed income      
Debt Instruments      
Financial assets € 4,239 € 4,557 € 5,632
Ireland | Public fixed income      
Debt Instruments      
Financial assets 42 14 11
Poland | Debt securities      
Debt Instruments      
Financial assets € 1,487 € 17,696 € 15,419
Financial assets (as a percent) 0.50% 6.24% 6.34%
Poland | Private fixed income      
Debt Instruments      
Financial assets € 22 € 2,472 € 2,937
Poland | Public fixed income      
Debt Instruments      
Financial assets 1,465 15,224 12,482
Other EU countries | Debt securities      
Debt Instruments      
Financial assets € 38,576 € 24,295 € 25,292
Financial assets (as a percent) 12.86% 8.57% 10.40%
Other EU countries | Private fixed income      
Debt Instruments      
Financial assets € 12,682 € 11,593 € 9,797
Other EU countries | Public fixed income      
Debt Instruments      
Financial assets 25,894 12,702 15,495
US | Debt securities      
Debt Instruments      
Financial assets € 44,140 € 40,286 € 31,951
Financial assets (as a percent) 14.71% 14.21% 13.14%
US | Private fixed income      
Debt Instruments      
Financial assets € 14,941 € 12,475 € 8,959
US | Public fixed income      
Debt Instruments      
Financial assets 29,199 27,811 22,992
Brazil | Debt securities      
Debt Instruments      
Financial assets € 47,426 € 45,383 € 45,893
Financial assets (as a percent) 15.81% 16.01% 18.87%
Brazil | Private fixed income      
Debt Instruments      
Financial assets € 13,518 € 12,738 € 13,551
Brazil | Public fixed income      
Debt Instruments      
Financial assets 33,908 32,645 32,342
Mexico | Debt securities      
Debt Instruments      
Financial assets € 28,114 € 23,012 € 22,707
Financial assets (as a percent) 9.37% 8.12% 9.34%
Mexico | Private fixed income      
Debt Instruments      
Financial assets € 3,001 € 2,190 € 1,969
Mexico | Public fixed income      
Debt Instruments      
Financial assets 25,113 20,822 20,738
Chile | Debt securities      
Debt Instruments      
Financial assets € 8,704 € 7,078 € 12,044
Financial assets (as a percent) 2.90% 2.50% 4.95%
Chile | Private fixed income      
Debt Instruments      
Financial assets € 137 € 96 € 49
Chile | Public fixed income      
Debt Instruments      
Financial assets 8,567 6,982 11,995
Other American countries | Debt securities      
Debt Instruments      
Financial assets € 9,208 € 7,838 € 4,861
Financial assets (as a percent) 3.07% 2.76% 2.00%
Other American countries | Private fixed income      
Debt Instruments      
Financial assets € 3,254 € 3,336 € 2,315
Other American countries | Public fixed income      
Debt Instruments      
Financial assets 5,954 4,502 2,546
Rest of the world | Debt securities      
Debt Instruments      
Financial assets € 4,382 € 7,150 € 5,429
Financial assets (as a percent) 1.45% 2.52% 2.23%
Rest of the world | Private fixed income      
Debt Instruments      
Financial assets € 1,125 € 1,100 € 806
Rest of the world | Public fixed income      
Debt Instruments      
Financial assets € 3,257 € 6,050 € 4,623