v3.26.1
Financial Risks - Summary of Maturity Analysis - Insurance and Reinsurance Contracts (Detail) - EUR (€)
€ in Millions
Dec. 31, 2025
Dec. 31, 2024
Disclosure of maturity analysis for liquidity risk that arises from contracts within scope of IFRS 17 [line items]    
Undiscounted best estimate liability € 382,890 € 422,841
Insurance contracts - Direct participating contracts [member]    
Disclosure of maturity analysis for liquidity risk that arises from contracts within scope of IFRS 17 [line items]    
Undiscounted best estimate liability 179,513 203,683
Insurance contracts - Without direct participation contracts [member]    
Disclosure of maturity analysis for liquidity risk that arises from contracts within scope of IFRS 17 [line items]    
Undiscounted best estimate liability 172,510 185,290
Investment contracts with DPF - Direct participating contracts [member]    
Disclosure of maturity analysis for liquidity risk that arises from contracts within scope of IFRS 17 [line items]    
Undiscounted best estimate liability 30,505 32,940
Reinsurance contracts held, in a liability position [member]    
Disclosure of maturity analysis for liquidity risk that arises from contracts within scope of IFRS 17 [line items]    
Undiscounted best estimate liability 362 928
Not later than 1 year [member]    
Disclosure of maturity analysis for liquidity risk that arises from contracts within scope of IFRS 17 [line items]    
Undiscounted best estimate liability 15,103 15,224
Not later than 1 year [member] | Insurance contracts - Direct participating contracts [member]    
Disclosure of maturity analysis for liquidity risk that arises from contracts within scope of IFRS 17 [line items]    
Undiscounted best estimate liability 10,502 10,086
Not later than 1 year [member] | Insurance contracts - Without direct participation contracts [member]    
Disclosure of maturity analysis for liquidity risk that arises from contracts within scope of IFRS 17 [line items]    
Undiscounted best estimate liability 2,455 3,238
Not later than 1 year [member] | Investment contracts with DPF - Direct participating contracts [member]    
Disclosure of maturity analysis for liquidity risk that arises from contracts within scope of IFRS 17 [line items]    
Undiscounted best estimate liability 2,136 1,880
Not later than 1 year [member] | Reinsurance contracts held, in a liability position [member]    
Disclosure of maturity analysis for liquidity risk that arises from contracts within scope of IFRS 17 [line items]    
Undiscounted best estimate liability 10 20
Later than one year and not later than two years [member]    
Disclosure of maturity analysis for liquidity risk that arises from contracts within scope of IFRS 17 [line items]    
Undiscounted best estimate liability 14,230 14,821
Later than one year and not later than two years [member] | Insurance contracts - Direct participating contracts [member]    
Disclosure of maturity analysis for liquidity risk that arises from contracts within scope of IFRS 17 [line items]    
Undiscounted best estimate liability 9,904 9,874
Later than one year and not later than two years [member] | Insurance contracts - Without direct participation contracts [member]    
Disclosure of maturity analysis for liquidity risk that arises from contracts within scope of IFRS 17 [line items]    
Undiscounted best estimate liability 2,288 2,962
Later than one year and not later than two years [member] | Investment contracts with DPF - Direct participating contracts [member]    
Disclosure of maturity analysis for liquidity risk that arises from contracts within scope of IFRS 17 [line items]    
Undiscounted best estimate liability 2,028 1,964
Later than one year and not later than two years [member] | Reinsurance contracts held, in a liability position [member]    
Disclosure of maturity analysis for liquidity risk that arises from contracts within scope of IFRS 17 [line items]    
Undiscounted best estimate liability 11 21
Later than two years and not later than three years [member]    
Disclosure of maturity analysis for liquidity risk that arises from contracts within scope of IFRS 17 [line items]    
Undiscounted best estimate liability 13,437 14,261
Later than two years and not later than three years [member] | Insurance contracts - Direct participating contracts [member]    
Disclosure of maturity analysis for liquidity risk that arises from contracts within scope of IFRS 17 [line items]    
Undiscounted best estimate liability 9,237 9,554
Later than two years and not later than three years [member] | Insurance contracts - Without direct participation contracts [member]    
Disclosure of maturity analysis for liquidity risk that arises from contracts within scope of IFRS 17 [line items]    
Undiscounted best estimate liability 2,330 2,777
Later than two years and not later than three years [member] | Investment contracts with DPF - Direct participating contracts [member]    
Disclosure of maturity analysis for liquidity risk that arises from contracts within scope of IFRS 17 [line items]    
Undiscounted best estimate liability 1,859 1,911
Later than two years and not later than three years [member] | Reinsurance contracts held, in a liability position [member]    
Disclosure of maturity analysis for liquidity risk that arises from contracts within scope of IFRS 17 [line items]    
Undiscounted best estimate liability 11 20
Later than three years and not later than four years [member]    
Disclosure of maturity analysis for liquidity risk that arises from contracts within scope of IFRS 17 [line items]    
Undiscounted best estimate liability 12,794 13,376
Later than three years and not later than four years [member] | Insurance contracts - Direct participating contracts [member]    
Disclosure of maturity analysis for liquidity risk that arises from contracts within scope of IFRS 17 [line items]    
Undiscounted best estimate liability 8,684 8,886
Later than three years and not later than four years [member] | Insurance contracts - Without direct participation contracts [member]    
Disclosure of maturity analysis for liquidity risk that arises from contracts within scope of IFRS 17 [line items]    
Undiscounted best estimate liability 2,438 2,782
Later than three years and not later than four years [member] | Investment contracts with DPF - Direct participating contracts [member]    
Disclosure of maturity analysis for liquidity risk that arises from contracts within scope of IFRS 17 [line items]    
Undiscounted best estimate liability 1,660 1,688
Later than three years and not later than four years [member] | Reinsurance contracts held, in a liability position [member]    
Disclosure of maturity analysis for liquidity risk that arises from contracts within scope of IFRS 17 [line items]    
Undiscounted best estimate liability 12 20
Later than four years and not later than five years [member]    
Disclosure of maturity analysis for liquidity risk that arises from contracts within scope of IFRS 17 [line items]    
Undiscounted best estimate liability 12,725 13,239
Later than four years and not later than five years [member] | Insurance contracts - Direct participating contracts [member]    
Disclosure of maturity analysis for liquidity risk that arises from contracts within scope of IFRS 17 [line items]    
Undiscounted best estimate liability 8,567 8,689
Later than four years and not later than five years [member] | Insurance contracts - Without direct participation contracts [member]    
Disclosure of maturity analysis for liquidity risk that arises from contracts within scope of IFRS 17 [line items]    
Undiscounted best estimate liability 2,531 2,849
Later than four years and not later than five years [member] | Investment contracts with DPF - Direct participating contracts [member]    
Disclosure of maturity analysis for liquidity risk that arises from contracts within scope of IFRS 17 [line items]    
Undiscounted best estimate liability 1,614 1,681
Later than four years and not later than five years [member] | Reinsurance contracts held, in a liability position [member]    
Disclosure of maturity analysis for liquidity risk that arises from contracts within scope of IFRS 17 [line items]    
Undiscounted best estimate liability 12 20
Later than 5 years [member]    
Disclosure of maturity analysis for liquidity risk that arises from contracts within scope of IFRS 17 [line items]    
Undiscounted best estimate liability 314,602 351,920
Later than 5 years [member] | Insurance contracts - Direct participating contracts [member]    
Disclosure of maturity analysis for liquidity risk that arises from contracts within scope of IFRS 17 [line items]    
Undiscounted best estimate liability 132,619 156,595
Later than 5 years [member] | Insurance contracts - Without direct participation contracts [member]    
Disclosure of maturity analysis for liquidity risk that arises from contracts within scope of IFRS 17 [line items]    
Undiscounted best estimate liability 160,468 170,682
Later than 5 years [member] | Investment contracts with DPF - Direct participating contracts [member]    
Disclosure of maturity analysis for liquidity risk that arises from contracts within scope of IFRS 17 [line items]    
Undiscounted best estimate liability 21,208 23,816
Later than 5 years [member] | Reinsurance contracts held, in a liability position [member]    
Disclosure of maturity analysis for liquidity risk that arises from contracts within scope of IFRS 17 [line items]    
Undiscounted best estimate liability € 306 € 827