v3.26.1
Insurance Net Investment Result - Summary of Other Investment Income Explanatory (Detail) - EUR (€)
€ in Millions
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Disclosure Of Insurance Net Investment Result In Other Investment Income [Line Items]      
Other Investment Income € 825 € 729 € 550
Income Or Loss From Insurance And Investment Contracts [Member]      
Disclosure Of Insurance Net Investment Result In Other Investment Income [Line Items]      
Other Investment Income 1,198 1,340 1,283
Dividend income [Member] | Income Or Loss From Insurance And Investment Contracts [Member]      
Disclosure Of Insurance Net Investment Result In Other Investment Income [Line Items]      
Other Investment Income 1,174 1,317 1,257
Rental income [Member] | Income Or Loss From Insurance And Investment Contracts [Member]      
Disclosure Of Insurance Net Investment Result In Other Investment Income [Line Items]      
Other Investment Income 25 23 26
Insurance Contracts With Direct Participating Features [Member] | Income Or Loss From Insurance And Investment Contracts [Member]      
Disclosure Of Insurance Net Investment Result In Other Investment Income [Line Items]      
Other Investment Income 785 816 845
Insurance Contracts With Direct Participating Features [Member] | Dividend income [Member] | Income Or Loss From Insurance And Investment Contracts [Member]      
Disclosure Of Insurance Net Investment Result In Other Investment Income [Line Items]      
Other Investment Income 769 801 828
Insurance Contracts With Direct Participating Features [Member] | Rental income [Member] | Income Or Loss From Insurance And Investment Contracts [Member]      
Disclosure Of Insurance Net Investment Result In Other Investment Income [Line Items]      
Other Investment Income 16 15 17
Insurance Contracts Without Direct Participating Features [Member] | Income Or Loss From Insurance And Investment Contracts [Member]      
Disclosure Of Insurance Net Investment Result In Other Investment Income [Line Items]      
Other Investment Income 10 10 11
Insurance Contracts Without Direct Participating Features [Member] | Dividend income [Member] | Income Or Loss From Insurance And Investment Contracts [Member]      
Disclosure Of Insurance Net Investment Result In Other Investment Income [Line Items]      
Other Investment Income 11 12 12
Insurance Contracts Without Direct Participating Features [Member] | Rental income [Member] | Income Or Loss From Insurance And Investment Contracts [Member]      
Disclosure Of Insurance Net Investment Result In Other Investment Income [Line Items]      
Other Investment Income (1) (2) (2)
Investment Contracts With Direct Participating Features [Member] | Income Or Loss From Insurance And Investment Contracts [Member]      
Disclosure Of Insurance Net Investment Result In Other Investment Income [Line Items]      
Other Investment Income 403 514 427
Investment Contracts With Direct Participating Features [Member] | Dividend income [Member] | Income Or Loss From Insurance And Investment Contracts [Member]      
Disclosure Of Insurance Net Investment Result In Other Investment Income [Line Items]      
Other Investment Income 394 504 417
Investment Contracts With Direct Participating Features [Member] | Rental income [Member] | Income Or Loss From Insurance And Investment Contracts [Member]      
Disclosure Of Insurance Net Investment Result In Other Investment Income [Line Items]      
Other Investment Income € 10 € 10 € 11