v3.26.1
Financial Risks - Additional Information (Detail) - EUR (€)
€ in Millions
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Disclosure of financial risk management [line items]        
Allowance for credit losses of financial assets € 17 € 18 € 18 € 10
Amount of undiscounted expected credit losses at initial recognition 1 4    
Amount held in general account investment readily redeemable and saleable 13,976 16,291    
Undrawn committed borrowing facilities € 1,351 1,544    
Percentage of equity market exposure 25.00%      
Bottom of range [member]        
Disclosure of financial risk management [line items]        
Percentage of increase or decrease in equity prices 10.00%      
Top of range [member]        
Disclosure of financial risk management [line items]        
Percentage of increase or decrease in equity prices 25.00%      
Debt securities [member]        
Disclosure of financial risk management [line items]        
Allowance for credit losses of financial assets € 347 341    
Mortgage loans [member]        
Disclosure of financial risk management [line items]        
Allowance for credit losses of financial assets 347 341 238  
Increase (decrease) in allowance for credit losses of financial assets   118    
Mortgage loans [member] | Bottom of range [member]        
Disclosure of financial risk management [line items]        
Increase (decrease) in allowance for credit losses of financial assets 85      
Mortgage loans [member] | Top of range [member]        
Disclosure of financial risk management [line items]        
Increase (decrease) in allowance for credit losses of financial assets 33      
Gross carrying amount [member]        
Disclosure of financial risk management [line items]        
Modification of financial assets 0 0    
Financial instruments purchased or originated credit-impaired [member]        
Disclosure of financial risk management [line items]        
Purchased or originated credit impaired financial assets recognized 0 0    
Financial instruments purchased or originated credit-impaired [member] | Mortgage loans [member]        
Disclosure of financial risk management [line items]        
Allowance for credit losses of financial assets 1 4 € 2  
Credit risk [member]        
Disclosure of financial risk management [line items]        
Maximum exposure to credit risk € 286,739 294,597    
Expected credit loss rate 80.00%      
Credit risk [member] | Later than three months and not later than six months [member]        
Disclosure of financial risk management [line items]        
Expected credit loss rate 60.00%      
Credit risk [member] | Not later than three months [member]        
Disclosure of financial risk management [line items]        
Expected credit loss rate 20.00%      
Credit risk [member] | Unconsolidated Investment Funds [member]        
Disclosure of financial risk management [line items]        
Maximum exposure to credit risk € 190,671 192,775    
Financial assets at fair value through profit or loss [member]        
Disclosure of financial risk management [line items]        
Maximum exposure to credit risk € 2,048 € 2,337