v3.26.1
Investment contracts without discretionary participation features - Summary of Investment contracts without discretionary participation features (Detail) - EUR (€)
€ in Millions
 6 Months Ended 12 Months Ended
Jun. 30, 2026
Dec. 31, 2025
Disclosure of investment contracts general and separate accounts [Line Items]    
Investment contracts liabilities € 41,839 € 97,814
Without Discretionary Participation Features [member]    
Disclosure of investment contracts general and separate accounts [Line Items]    
Investment contracts liabilities 41,839 97,814
Without Discretionary Participation Features [member] | Aegon Risk [Member]    
Disclosure of investment contracts general and separate accounts [Line Items]    
Beginning balance on January 1 12,652 12,592
Deposits 816 1,798
Withdrawals (840) (1,653)
Interest credited 180 354
Fund charges released (30) (15)
Net exchange differences 362 (1,535)
Transfer to / from other headings 461 1,113
Other movements (2) (2)
Ending balance 13,570 12,652
Investment Contracts For General Account Transfers to Disposal Groups (31) 0
Investment contracts liabilities 13,570 12,652
Without Discretionary Participation Features [member] | Policyholder Risk [Member]    
Disclosure of investment contracts general and separate accounts [Line Items]    
Beginning balance on January 1 85,161 79,078
Deposits 4,875 15,135
Withdrawals (4,279) (12,788)
Investment Contracts For General Account Transfers to Disposal Groups (59,035) 0
Interest credited 1,033 11,004
Fund charges released (154) (384)
Net exchange differences 1,121 (6,241)
Transfer to/from other headings (453) (647)
Other movements 0 4
Ending balance 28,269 85,161
Investment contracts liabilities € 28,269 € 85,161