v3.26.1
Schedule III - Disclosure of Supplementary Insurance Information (Detail) - EUR (€)
€ in Millions
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Disclosure of supplementary insurance information [line items]      
Investment income [1] € 6,176 € 6,217 € 5,995
Insurance liability - CSM 8,604 9,192  
Insurance liability - BEL 185,470 198,050  
Insurance liability - RA 3,231 3,408  
Insurance liability - PAA contracts 44 41  
Insurance revenue 197,349 210,691  
Insurance revenue 9,097 9,841 10,386
Insurance service expenses 9,423 9,790 10,226
Other operating expenses 2,928 2,961 2,961
Americas [member]      
Disclosure of supplementary insurance information [line items]      
Investment income [1] 3,474 3,480 3,461
Insurance liability - CSM 6,943 7,298  
Insurance liability - BEL 120,686 132,762  
Insurance liability - RA 2,818 2,937  
Insurance liability - PAA contracts 0 0  
Insurance revenue 130,447 142,996  
Insurance revenue 8,477 9,102 9,468
Insurance service expenses 9,198 9,298 9,578
Other operating expenses 1,919 2,044 2,148
United Kingdom [member]      
Disclosure of supplementary insurance information [line items]      
Investment income [1] 2,590 2,589 2,362
Insurance liability - CSM 1,557 1,698  
Insurance liability - BEL 64,087 64,597  
Insurance liability - RA 330 376  
Insurance liability - PAA contracts 0 0  
Insurance revenue 65,974 66,671  
Insurance revenue 422 543 663
Insurance service expenses 183 302 406
Other operating expenses 445 434 353
International [Member]      
Disclosure of supplementary insurance information [line items]      
Investment income [1] 57 68 86
Insurance liability - CSM 126 237  
Insurance liability - BEL 4,926 5,803  
Insurance liability - RA 124 162  
Insurance liability - PAA contracts 44 41  
Insurance revenue 5,220 6,243  
Insurance revenue 237 240 305
Insurance service expenses 294 257 275
Other operating expenses 103 91 93
Asset management [member]      
Disclosure of supplementary insurance information [line items]      
Investment income [1] 16 15 2
Insurance liability - CSM 0 0  
Insurance liability - BEL 0 0  
Insurance liability - RA 0 0  
Insurance liability - PAA contracts 0 0  
Insurance revenue 0 0  
Insurance revenue 0    
Insurance service expenses 0    
Other operating expenses 411 459 440
Holding and other activities [member]      
Disclosure of supplementary insurance information [line items]      
Investment income [1] 46 76 90
Insurance liability - CSM 0 0  
Insurance liability - BEL 0 0  
Insurance liability - RA 0 0  
Insurance liability - PAA contracts 0 0  
Insurance revenue 0 0  
Insurance revenue 0    
Insurance service expenses 0    
Other operating expenses 197 85 85
Elimination [member]      
Disclosure of supplementary insurance information [line items]      
Investment income [1] (7) (11) (6)
Insurance liability - CSM (23) (40)  
Insurance liability - BEL (4,229) (5,112)  
Insurance liability - RA (41) (67)  
Insurance liability - PAA contracts 0 0  
Insurance revenue (4,292) (5,219)  
Insurance revenue (39) (45) (51)
Insurance service expenses (253) (68) (33)
Other operating expenses € (147) € (153) € (158)
[1] Sum of Interest revenue on financial instruments calculated using the effective interest method, Interest revenue on financial instruments measured at FVPL and Other investment income