v3.25.2
Fair value of assets and liabilities - Valuation techniques and range of unobservable inputs (Details)
€ in Millions
 6 Months Ended 12 Months Ended
Jun. 30, 2025
EUR (€)
€ / shares
Dec. 31, 2024
EUR (€)
€ / shares
Dec. 31, 2023
EUR (€)
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Financial assets at fair value through profit or loss € 152,486 € 137,580  
Financial assets at fair value through other comprehensive income 49,846 46,389  
Financial liabilities at fair value through profit or loss 93,524 86,900  
Level 3      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Financial assets at fair value through profit or loss 11,157 10,734  
Financial assets at fair value through other comprehensive income 440 270  
Total financial assets 11,597 11,005 € 9,118
Financial liabilities at fair value through profit or loss 613 770  
Financial liabilities, at fair value 613 770 € 729
Level 3 | Debt securities      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Financial assets at fair value through profit or loss 2,580 3,504  
Financial liabilities at fair value through profit or loss 10 10  
Level 3 | Equity securities      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Financial assets at fair value through profit or loss 145 141  
Level 3 | Loans and advances      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Financial assets at fair value through profit or loss 1,950 1,565  
Financial liabilities at fair value through profit or loss 0 0  
Level 3 | (Reverse) repos      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Financial assets at fair value through profit or loss 5,783 5,050  
Level 3 | Structured notes      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Financial liabilities at fair value through profit or loss 53 67  
Level 3 | Derivatives at rates      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Financial assets at fair value through profit or loss 494 413  
Financial liabilities at fair value through profit or loss 477 389  
Level 3 | Derivatives at foreign exchange      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Financial assets at fair value through profit or loss 5 6  
Financial liabilities at fair value through profit or loss 4 8  
Level 3 | Derivative at credit      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Financial assets at fair value through profit or loss 181 39  
Financial liabilities at fair value through profit or loss 33 241  
Level 3 | Derivatives at equity      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Financial assets at fair value through profit or loss 7 10  
Financial liabilities at fair value through profit or loss 21 47  
Level 3 | Other derivatives      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Financial assets at fair value through profit or loss 13 6  
Financial liabilities at fair value through profit or loss 15 9  
Level 3 | Loan and advances at FVOCI      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Financial assets at fair value through other comprehensive income 156    
Level 3 | Equity at FVOCI      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Financial assets at fair value through other comprehensive income € 283 € 270  
Level 3 | Minimum | Price based | Debt securities | Price (%)      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, percentage 0 0  
Level 3 | Minimum | Price based | Debt securities | Price (price per share)      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, price (in EUR per share) | € / shares 417 327  
Level 3 | Minimum | Price based | Equity securities | Price (price per share)      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, price (in EUR per share) | € / shares 0 0  
Level 3 | Minimum | Price based | Loans and advances | Price (%)      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, percentage 0 0  
Level 3 | Minimum | Price based | Structured notes | Price (%)      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, percentage 0.94 0.93  
Level 3 | Minimum | Price based | Derivative at credit | Price (%)      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, percentage 0.94 0  
Level 3 | Minimum | Price based | Other derivatives | Price (%)      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, percentage 67 68  
Level 3 | Minimum | Price based | Equity at FVOCI | Price (%)      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, percentage   1.22  
Level 3 | Minimum | Price based | Equity at FVOCI | Price (price per share)      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, price (in EUR per share) | € / shares 125.74    
Level 3 | Minimum | Present value techniques | Debt securities | Price (%)      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, percentage 0.96 0.96  
Level 3 | Minimum | Present value techniques | Loans and advances | Price (%)      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, percentage 1    
Level 3 | Minimum | Present value techniques | Loans and advances | Credit spread (bps)      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, percentage 0.0628 0.0576  
Level 3 | Minimum | Present value techniques | Loans and advances | Prepayment rate (%)      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, percentage 0.02 0.02  
Level 3 | Minimum | Present value techniques | (Reverse) repos | Interest rate (%)      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, percentage 0.02 0.02  
Level 3 | Minimum | Present value techniques | Structured notes | Price (%)      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, percentage 1    
Level 3 | Minimum | Present value techniques | Structured notes | Prepayment rate (%)      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, percentage   0.9959  
Level 3 | Minimum | Present value techniques | Derivatives at rates | Reset spread (%)      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, percentage 0.02 0.02  
Level 3 | Minimum | Present value techniques | Derivative at credit | Credit spread (bps)      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, percentage 0.0008 0  
Level 3 | Minimum | Present value techniques | Equity at FVOCI | Credit spread (bps)      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, percentage 0.000552 0.000567  
Level 3 | Minimum | Present value techniques | Equity at FVOCI | Interest rate (%)      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, percentage 0.035 0.015  
Level 3 | Minimum | Present value techniques | Equity at FVOCI | Payout ratio (%)      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, percentage 0.70 0.70  
Level 3 | Minimum | Option pricing model | Structured notes | Equity volatility (%)      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, percentage 0.16    
Level 3 | Minimum | Option pricing model | Structured notes | Equity/Equity correlation      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, percentage 0.6 0.7  
Level 3 | Minimum | Option pricing model | Structured notes | Equity/FX correlation      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, percentage (0.2)    
Level 3 | Minimum | Option pricing model | Structured notes | Dividend yield (%)      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, percentage 0.037    
Level 3 | Minimum | Option pricing model | Derivatives at rates | Interest rate volatility (bps)      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, percentage 0.0064    
Level 3 | Minimum | Option pricing model | Derivatives at foreign exchange | Implied volatility (%)      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, percentage 0.02 0.02  
Level 3 | Minimum | Option pricing model | Derivatives at equity | Equity volatility (%)      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, percentage 0.07 0.07  
Level 3 | Minimum | Option pricing model | Derivatives at equity | Equity/Equity correlation      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, percentage 0.0 0.0  
Level 3 | Minimum | Option pricing model | Derivatives at equity | Equity/FX correlation      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, percentage (0.6) (0.6)  
Level 3 | Minimum | Option pricing model | Derivatives at equity | Dividend yield (%)      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, percentage 0 0  
Level 3 | Minimum | Option pricing model | Other derivatives | Commodity volatility (%)      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, percentage 0.15 0.131  
Level 3 | Minimum | Option pricing model | Other derivatives | Com/FX correlation      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, percentage (0.25) (0.40)  
Level 3 | Maximum | Price based | Debt securities | Price (%)      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, percentage 1.08 1.20  
Level 3 | Maximum | Price based | Debt securities | Price (price per share)      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, price (in EUR per share) | € / shares 1,325 520  
Level 3 | Maximum | Price based | Equity securities | Price (price per share)      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, price (in EUR per share) | € / shares 5,475 5,475  
Level 3 | Maximum | Price based | Loans and advances | Price (%)      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, percentage 1.05 1.07  
Level 3 | Maximum | Price based | Structured notes | Price (%)      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, percentage 1.03 1.04  
Level 3 | Maximum | Price based | Derivative at credit | Price (%)      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, percentage 1 1  
Level 3 | Maximum | Price based | Other derivatives | Price (%)      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, percentage 67 68  
Level 3 | Maximum | Price based | Equity at FVOCI | Price (%)      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, percentage   1.22  
Level 3 | Maximum | Price based | Equity at FVOCI | Price (price per share)      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, price (in EUR per share) | € / shares 125.74    
Level 3 | Maximum | Present value techniques | Debt securities | Price (%)      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, percentage 0.99 1  
Level 3 | Maximum | Present value techniques | Loans and advances | Price (%)      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, percentage 1    
Level 3 | Maximum | Present value techniques | Loans and advances | Credit spread (bps)      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, percentage 0.0707 0.0629  
Level 3 | Maximum | Present value techniques | Loans and advances | Prepayment rate (%)      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, percentage 0.02 1  
Level 3 | Maximum | Present value techniques | (Reverse) repos | Interest rate (%)      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, percentage 0.02 0.02  
Level 3 | Maximum | Present value techniques | Structured notes | Price (%)      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, percentage 1    
Level 3 | Maximum | Present value techniques | Structured notes | Prepayment rate (%)      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, percentage   1.0009  
Level 3 | Maximum | Present value techniques | Derivatives at rates | Reset spread (%)      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, percentage 0.02 0.02  
Level 3 | Maximum | Present value techniques | Derivative at credit | Credit spread (bps)      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, percentage 0.0094 0.0091  
Level 3 | Maximum | Present value techniques | Equity at FVOCI | Credit spread (bps)      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, percentage 0.000552 0.000576  
Level 3 | Maximum | Present value techniques | Equity at FVOCI | Interest rate (%)      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, percentage 0.035 0.035  
Level 3 | Maximum | Present value techniques | Equity at FVOCI | Payout ratio (%)      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, percentage 0.90 0.90  
Level 3 | Maximum | Option pricing model | Structured notes | Equity volatility (%)      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, percentage 0.46    
Level 3 | Maximum | Option pricing model | Structured notes | Equity/Equity correlation      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, percentage 0.7 0.7  
Level 3 | Maximum | Option pricing model | Structured notes | Equity/FX correlation      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, percentage 0    
Level 3 | Maximum | Option pricing model | Structured notes | Dividend yield (%)      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, percentage 0.043    
Level 3 | Maximum | Option pricing model | Derivatives at rates | Interest rate volatility (bps)      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, percentage 0.0280    
Level 3 | Maximum | Option pricing model | Derivatives at foreign exchange | Implied volatility (%)      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, percentage 0.41 0.15  
Level 3 | Maximum | Option pricing model | Derivatives at equity | Equity volatility (%)      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, percentage 0.76 0.81  
Level 3 | Maximum | Option pricing model | Derivatives at equity | Equity/Equity correlation      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, percentage 1.0 1.0  
Level 3 | Maximum | Option pricing model | Derivatives at equity | Equity/FX correlation      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, percentage 0.3 0.6  
Level 3 | Maximum | Option pricing model | Derivatives at equity | Dividend yield (%)      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, percentage 1 0.33  
Level 3 | Maximum | Option pricing model | Other derivatives | Commodity volatility (%)      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, percentage 0.93 0.61  
Level 3 | Maximum | Option pricing model | Other derivatives | Com/FX correlation      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, percentage (0.25) (0.25)