v3.26.1
Financial Risks - Summary of Market Risk Concentrations in Shares (Detail) - Concentration Risk By Type [member] - EUR (€)
€ in Millions
Dec. 31, 2025
Dec. 31, 2024
Summary of market risk concentrations in shares [Line Items]    
Market risk concentrations - shares € 273 € 317
Communication [member]    
Summary of market risk concentrations in shares [Line Items]    
Market risk concentrations - shares 1 2
Consumer [member]    
Summary of market risk concentrations in shares [Line Items]    
Market risk concentrations - shares 7 2
Financials [member]    
Summary of market risk concentrations in shares [Line Items]    
Market risk concentrations - shares 22 28
Funds [member]    
Summary of market risk concentrations in shares [Line Items]    
Market risk concentrations - shares 169 154
Industries [member]    
Summary of market risk concentrations in shares [Line Items]    
Market risk concentrations - shares 12 6
Other [member]    
Summary of market risk concentrations in shares [Line Items]    
Market risk concentrations - shares 63 125
Americas [member]    
Summary of market risk concentrations in shares [Line Items]    
Market risk concentrations - shares 211 256
Americas [member] | Communication [member]    
Summary of market risk concentrations in shares [Line Items]    
Market risk concentrations - shares 1 2
Americas [member] | Consumer [member]    
Summary of market risk concentrations in shares [Line Items]    
Market risk concentrations - shares 7 2
Americas [member] | Financials [member]    
Summary of market risk concentrations in shares [Line Items]    
Market risk concentrations - shares 16 23
Americas [member] | Funds [member]    
Summary of market risk concentrations in shares [Line Items]    
Market risk concentrations - shares 125 140
Americas [member] | Industries [member]    
Summary of market risk concentrations in shares [Line Items]    
Market risk concentrations - shares 12 6
Americas [member] | Other [member]    
Summary of market risk concentrations in shares [Line Items]    
Market risk concentrations - shares 50 83
United Kingdom [member]    
Summary of market risk concentrations in shares [Line Items]    
Market risk concentrations - shares 16 14
United Kingdom [member] | Funds [member]    
Summary of market risk concentrations in shares [Line Items]    
Market risk concentrations - shares 16 14
International [member]    
Summary of market risk concentrations in shares [Line Items]    
Market risk concentrations - shares 37 39
International [member] | Financials [member]    
Summary of market risk concentrations in shares [Line Items]    
Market risk concentrations - shares 6 5
International [member] | Funds [member]    
Summary of market risk concentrations in shares [Line Items]    
Market risk concentrations - shares 27  
International [member] | Other [member]    
Summary of market risk concentrations in shares [Line Items]    
Market risk concentrations - shares 4 33
Asset management [member]    
Summary of market risk concentrations in shares [Line Items]    
Market risk concentrations - shares 9 9
Asset management [member] | Other [member]    
Summary of market risk concentrations in shares [Line Items]    
Market risk concentrations - shares € 9 € 9