v3.25.4
Fair value of assets and liabilities - Valuation techniques and range of unobservable inputs (Details)
€ in Millions
 12 Months Ended
Dec. 31, 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 € 133,157 € 137,580  
Financial assets at fair value through other comprehensive income 56,662 46,389  
Financial liabilities at fair value through profit or loss 80,532 86,900  
- Debt securities      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Financial assets at fair value through other comprehensive income 50,817 42,219  
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 11,435 10,734  
Financial assets at fair value through other comprehensive income 307 270  
Total financial assets 11,742 11,005 € 9,118
Financial liabilities at fair value through profit or loss 802 770  
Financial liabilities, at fair value € 802 € 770 € 729
Level 3 | - Debt securities | Price (%) | Minimum | Present value techniques      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, percentage   95.85%  
Level 3 | - Debt securities | Price (%) | Maximum | Present value techniques      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, percentage   100.00%  
Level 3 | - Debt securities | Price (price per share) | Minimum | Price based      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, price (in EUR per share) | € / shares 201 327  
Level 3 | - Debt securities | Price (price per share) | Maximum | Price based      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, price (in EUR per share) | € / shares 412 520  
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 € 1,978 € 1,565  
Financial liabilities at fair value through profit or loss € 0 € 0  
Level 3 | Loans and advances | Price (%) | Minimum | Price based      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, percentage 0.00% 0.00%  
Level 3 | Loans and advances | Price (%) | Maximum | Price based      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, percentage 109.00% 107.00%  
Level 3 | Loans and advances | Credit spread (bps) | Minimum | Present value techniques      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, basis point spread 0.0120 0.0576  
Level 3 | Loans and advances | Credit spread (bps) | Maximum | Present value techniques      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, basis point spread 0.0709 0.0629  
Level 3 | Loans and advances | Prepayment rate (%) | Minimum | Present value techniques      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, basis point spread 0.02 0.02  
Level 3 | Loans and advances | Prepayment rate (%) | Maximum | Present value techniques      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, basis point spread 0.02 1  
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 € 6,563 € 5,050  
Level 3 | (Reverse) repos | Interest rate (%) | Minimum | Present value techniques      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, basis point spread   0.02  
Level 3 | (Reverse) repos | Interest rate (%) | Maximum | Present value techniques      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, basis point spread   0.02  
Level 3 | Structured notes      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Financial assets at fair value through profit or loss  
Financial liabilities at fair value through profit or loss € 15 € 67  
Level 3 | Structured notes | Price (%) | Minimum | Price based      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, percentage 96.00% 93.00%  
Level 3 | Structured notes | Price (%) | Maximum | Price based      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, percentage 103.00% 104.00%  
Level 3 | Structured notes | Equity volatility (%) | Minimum | Option pricing model      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, percentage 18.00%    
Level 3 | Structured notes | Equity volatility (%) | Maximum | Option pricing model      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, percentage 22.00%    
Level 3 | Structured notes | Equity/Equity correlation | Minimum | Option pricing model      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, correlation 0.7 0.7  
Level 3 | Structured notes | Equity/Equity correlation | Maximum | Option pricing model      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, correlation 0.8 0.7  
Level 3 | Structured notes | Equity/FX correlation | Minimum | Option pricing model      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, correlation (0.6)    
Level 3 | Structured notes | Equity/FX correlation | Maximum | Option pricing model      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, correlation 0.2    
Level 3 | Structured notes | Dividend yield (%) | Minimum | Option pricing model      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, percentage 0.40%    
Level 3 | Structured notes | Dividend yield (%) | Maximum | Option pricing model      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, percentage 1.90%    
Level 3 | Structured notes | Prepayment rate (%) | Minimum | Present value techniques      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, basis point spread   0.9959  
Level 3 | Structured notes | Prepayment rate (%) | Maximum | Present value techniques      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, basis point spread   1.0009  
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 € 628 € 413  
Financial liabilities at fair value through profit or loss € 670 € 389  
Level 3 | Derivatives at rates | Interest rate volatility (bps) | Minimum | Option pricing model      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, basis point spread 0.0045    
Level 3 | Derivatives at rates | Interest rate volatility (bps) | Maximum | Option pricing model      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, basis point spread 0.0091    
Level 3 | Derivatives at rates | Reset spread (%) | Minimum | Present value techniques      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, percentage 1.00% 2.00%  
Level 3 | Derivatives at rates | Reset spread (%) | Maximum | Present value techniques      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, percentage 1.00% 2.00%  
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 € 2 € 6  
Financial liabilities at fair value through profit or loss € 4 € 8  
Level 3 | Derivatives at foreign exchange | Implied volatility (%) | Minimum | Option pricing model      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, percentage 1.70% 2.00%  
Level 3 | Derivatives at foreign exchange | Implied volatility (%) | Maximum | Option pricing model      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, percentage 42.00% 15.00%  
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 € 134 € 39  
Financial liabilities at fair value through profit or loss € 48 € 241  
Level 3 | Derivative at credit | Price (%) | Minimum | Price based      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, percentage 0.00% 0.00%  
Level 3 | Derivative at credit | Price (%) | Maximum | Price based      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, percentage 100.00% 100.00%  
Level 3 | Derivative at credit | Credit spread (bps) | Minimum | Present value techniques      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, basis point spread 0.0010 0  
Level 3 | Derivative at credit | Credit spread (bps) | Maximum | Present value techniques      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, basis point spread 0.0088 0.0091  
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 € 46 € 47  
Level 3 | Derivatives at equity | Equity volatility (%) | Minimum | Option pricing model      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, percentage 13.00% 7.00%  
Level 3 | Derivatives at equity | Equity volatility (%) | Maximum | Option pricing model      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, percentage 75.00% 81.00%  
Level 3 | Derivatives at equity | Equity/Equity correlation | Minimum | Option pricing model      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, correlation 0.0 0.0  
Level 3 | Derivatives at equity | Equity/Equity correlation | Maximum | Option pricing model      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, correlation 1.0 1.0  
Level 3 | Derivatives at equity | Equity/FX correlation | Minimum | Option pricing model      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, correlation (0.7) (0.6)  
Level 3 | Derivatives at equity | Equity/FX correlation | Maximum | Option pricing model      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, correlation 0.5 0.6  
Level 3 | Derivatives at equity | Dividend yield (%) | Minimum | Option pricing model      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, percentage 0.00% 0.00%  
Level 3 | Derivatives at equity | Dividend yield (%) | Maximum | Option pricing model      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, percentage 51.00% 33.00%  
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 € 2 € 6  
Financial liabilities at fair value through profit or loss € 10 € 9  
Level 3 | Other derivatives | Price (price per share) | Minimum | Price based      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, correlation 66 68  
Level 3 | Other derivatives | Price (price per share) | Maximum | Price based      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, correlation 66 68  
Level 3 | Other derivatives | Commodity volatility (%) | Minimum | Option pricing model      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, percentage 20.00% 13.10%  
Level 3 | Other derivatives | Commodity volatility (%) | Maximum | Option pricing model      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, percentage 76.00% 61.00%  
Level 3 | Other derivatives | Com/FX correlation | Minimum | Option pricing model      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, correlation (0.25) (0.40)  
Level 3 | Other derivatives | Com/FX correlation | Maximum | Option pricing model      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, correlation (0.25) (0.25)  
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 € 307 € 270  
Level 3 | Equity at FVOCI | Price (%) | Minimum | Price based      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, percentage   122.00%  
Level 3 | Equity at FVOCI | Price (%) | Maximum | Price based      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, percentage   122.00%  
Level 3 | Equity at FVOCI | Price (price per share) | Minimum | Price based      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, price (in EUR per share) 126    
Level 3 | Equity at FVOCI | Price (price per share) | Maximum | Price based      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, price (in EUR per share) 126    
Level 3 | Equity at FVOCI | Credit spread (bps) | Minimum | Present value techniques      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, basis point spread 0.000515 0.000567  
Level 3 | Equity at FVOCI | Credit spread (bps) | Maximum | Present value techniques      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, basis point spread 0.000515 0.000576  
Level 3 | Equity at FVOCI | Interest rate (%) | Minimum | Present value techniques      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, percentage 2.50% 1.50%  
Level 3 | Equity at FVOCI | Interest rate (%) | Maximum | Present value techniques      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, percentage 2.50% 3.50%  
Level 3 | Equity at FVOCI | Payout ratio (%) | Minimum | Present value techniques      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, percentage 70.00% 70.00%  
Level 3 | Equity at FVOCI | Payout ratio (%) | Maximum | Present value techniques      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, percentage 90.00% 90.00%  
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 € 187 € 141  
Level 3 | Equity securities | Price (price per share) | Minimum | Price based      
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 | Equity securities | Price (price per share) | Maximum | Price based      
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 | - 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 € 1,934 € 3,504  
Financial assets at fair value through other comprehensive income 0 0  
Financial liabilities at fair value through profit or loss € 9 € 10  
Level 3 | - Debt securities | - Debt securities | Price (%) | Minimum | Price based      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, percentage 0.00% 0.00%  
Level 3 | - Debt securities | - Debt securities | Price (%) | Maximum | Price based      
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]      
Significant unobservable inputs, percentage 103.00% 120.00%