v3.26.1
Other disclosures - Summary of fair values of financial assets and liabilities (Details) - EUR (€)
€ in Millions
Jun. 30, 2026
Dec. 31, 2025
Disclosure of detailed information about financial instruments [line items]    
Financial assets held for trading € 286,941 € 252,318
Non-trading financial assets mandatorily at fair value through profit or loss 8,058 7,761
Financial assets designated at fair value through profit or loss 7,884 8,046
Financial assets designated at fair value through other comprehensive income 75,371 74,612
Hedging derivatives (assets) 5,006 3,931
Financial liabilities held for trading 193,417 171,546
Financial liabilities designated at fair value through profit or loss 43,407 42,148
Hedging derivatives (liabilities) 4,494 4,248
Liabilities under insurance contracts 19,347 18,737
Level 1    
Disclosure of detailed information about financial instruments [line items]    
Financial assets held for trading 120,390 106,529
Non-trading financial assets mandatorily at fair value through profit or loss 2,647 2,407
Financial assets designated at fair value through profit or loss 2,857 2,860
Financial assets designated at fair value through other comprehensive income 53,995 52,589
Financial liabilities held for trading 34,617 37,192
Level 2    
Disclosure of detailed information about financial instruments [line items]    
Financial assets held for trading 158,735 139,293
Non-trading financial assets mandatorily at fair value through profit or loss 2,413 2,465
Financial assets designated at fair value through profit or loss 4,976 5,152
Financial assets designated at fair value through other comprehensive income 11,384 12,962
Hedging derivatives (assets) 5,006 3,924
Financial liabilities held for trading 157,680 133,490
Financial liabilities designated at fair value through profit or loss 43,279 42,148
Hedging derivatives (liabilities) 4,490 4,229
Liabilities under insurance contracts 19,103 18,510
Level 3    
Disclosure of detailed information about financial instruments [line items]    
Financial assets held for trading 7,816 6,496
Non-trading financial assets mandatorily at fair value through profit or loss 2,998 2,889
Financial assets designated at fair value through profit or loss 51 34
Financial assets designated at fair value through other comprehensive income 9,992 9,061
Hedging derivatives (assets) 0 7
Financial liabilities held for trading 1,120 864
Financial liabilities designated at fair value through profit or loss 128 0
Hedging derivatives (liabilities) 4 19
Liabilities under insurance contracts € 244 € 227