v3.26.1
Fair value - Summary of the Analysis of Assets and Liabilities Recorded at Fair Value on a Recurring Basis by Level of the Fair Value Hierarchy (Detail) - Recurring fair value measurement [member] - EUR (€)
€ in Millions
Jun. 30, 2026
Dec. 31, 2025
Disclosure of fair value measurement of assets and liabilities [line items]    
Assets carried at fair value € 158,293 € 275,428
Liabilities carried at fair value 29,538 86,630
Fair value through other comprehensive income [member]    
Disclosure of fair value measurement of assets and liabilities [line items]    
Assets carried at fair value 52,541 49,757
Financial assets at fair value through profit or loss, category [member]    
Disclosure of fair value measurement of assets and liabilities [line items]    
Assets carried at fair value 105,752 225,671
Shares [member] | Fair value through other comprehensive income [member]    
Disclosure of fair value measurement of assets and liabilities [line items]    
Assets carried at fair value 10 10
Shares [member] | Financial assets at fair value through profit or loss, category [member]    
Disclosure of fair value measurement of assets and liabilities [line items]    
Assets carried at fair value 247 263
Debt securities [member] | Fair value through other comprehensive income [member]    
Disclosure of fair value measurement of assets and liabilities [line items]    
Assets carried at fair value 50,293 47,411
Debt securities [member] | Financial assets at fair value through profit or loss, category [member]    
Disclosure of fair value measurement of assets and liabilities [line items]    
Assets carried at fair value 2,158 2,438
Money Markets and other short-term investment [member] | Fair value through other comprehensive income [member]    
Disclosure of fair value measurement of assets and liabilities [line items]    
Assets carried at fair value 2,209 2,308
Money Markets and other short-term investment [member] | Financial assets at fair value through profit or loss, category [member]    
Disclosure of fair value measurement of assets and liabilities [line items]    
Assets carried at fair value 1,089 1,868
Loans [member] | Financial assets at fair value through profit or loss, category [member]    
Disclosure of fair value measurement of assets and liabilities [line items]    
Assets carried at fair value 84 82
Other investments at fair value [member] | Fair value through other comprehensive income [member]    
Disclosure of fair value measurement of assets and liabilities [line items]    
Assets carried at fair value 29 28
Other investments at fair value [member] | Financial assets at fair value through profit or loss, category [member]    
Disclosure of fair value measurement of assets and liabilities [line items]    
Assets carried at fair value 3,967 4,721
Derivatives [member] | Financial assets at fair value through profit or loss, category [member]    
Disclosure of fair value measurement of assets and liabilities [line items]    
Assets carried at fair value 681 485
Investments - Policyholder Risk [Member] | Financial assets at fair value through profit or loss, category [member]    
Disclosure of fair value measurement of assets and liabilities [line items]    
Assets carried at fair value 97,527 215,814
Investment contracts without DPF - Policyholder risk [member]    
Disclosure of fair value measurement of assets and liabilities [line items]    
Liabilities carried at fair value 28,269 85,161
Derivatives [member]    
Disclosure of fair value measurement of assets and liabilities [line items]    
Liabilities carried at fair value 1,269 1,469
Level I [member]    
Disclosure of fair value measurement of assets and liabilities [line items]    
Assets carried at fair value 83,746 98,158
Liabilities carried at fair value 8 50
Level I [member] | Fair value through other comprehensive income [member]    
Disclosure of fair value measurement of assets and liabilities [line items]    
Assets carried at fair value 6,167 6,272
Level I [member] | Financial assets at fair value through profit or loss, category [member]    
Disclosure of fair value measurement of assets and liabilities [line items]    
Assets carried at fair value 77,579 91,886
Level I [member] | Shares [member] | Fair value through other comprehensive income [member]    
Disclosure of fair value measurement of assets and liabilities [line items]    
Assets carried at fair value 5 5
Level I [member] | Shares [member] | Financial assets at fair value through profit or loss, category [member]    
Disclosure of fair value measurement of assets and liabilities [line items]    
Assets carried at fair value 185 179
Level I [member] | Debt securities [member] | Fair value through other comprehensive income [member]    
Disclosure of fair value measurement of assets and liabilities [line items]    
Assets carried at fair value 4,350 4,165
Level I [member] | Debt securities [member] | Financial assets at fair value through profit or loss, category [member]    
Disclosure of fair value measurement of assets and liabilities [line items]    
Assets carried at fair value 12 253
Level I [member] | Money Markets and other short-term investment [member] | Fair value through other comprehensive income [member]    
Disclosure of fair value measurement of assets and liabilities [line items]    
Assets carried at fair value 1,812 2,102
Level I [member] | Money Markets and other short-term investment [member] | Financial assets at fair value through profit or loss, category [member]    
Disclosure of fair value measurement of assets and liabilities [line items]    
Assets carried at fair value 1,089 1,708
Level I [member] | Other investments at fair value [member] | Financial assets at fair value through profit or loss, category [member]    
Disclosure of fair value measurement of assets and liabilities [line items]    
Assets carried at fair value 21 18
Level I [member] | Derivatives [member] | Financial assets at fair value through profit or loss, category [member]    
Disclosure of fair value measurement of assets and liabilities [line items]    
Assets carried at fair value 60 14
Level I [member] | Investments - Policyholder Risk [Member] | Financial assets at fair value through profit or loss, category [member]    
Disclosure of fair value measurement of assets and liabilities [line items]    
Assets carried at fair value 76,213 89,715
Level I [member] | Derivatives [member]    
Disclosure of fair value measurement of assets and liabilities [line items]    
Liabilities carried at fair value 8 50
Level II [member]    
Disclosure of fair value measurement of assets and liabilities [line items]    
Assets carried at fair value 69,546 172,107
Liabilities carried at fair value 29,531 86,580
Level II [member] | Fair value through other comprehensive income [member]    
Disclosure of fair value measurement of assets and liabilities [line items]    
Assets carried at fair value 45,673 42,951
Level II [member] | Financial assets at fair value through profit or loss, category [member]    
Disclosure of fair value measurement of assets and liabilities [line items]    
Assets carried at fair value 23,873 129,156
Level II [member] | Shares [member] | Financial assets at fair value through profit or loss, category [member]    
Disclosure of fair value measurement of assets and liabilities [line items]    
Assets carried at fair value 13 30
Level II [member] | Debt securities [member] | Fair value through other comprehensive income [member]    
Disclosure of fair value measurement of assets and liabilities [line items]    
Assets carried at fair value 45,248 42,717
Level II [member] | Debt securities [member] | Financial assets at fair value through profit or loss, category [member]    
Disclosure of fair value measurement of assets and liabilities [line items]    
Assets carried at fair value 2,019 2,075
Level II [member] | Money Markets and other short-term investment [member] | Fair value through other comprehensive income [member]    
Disclosure of fair value measurement of assets and liabilities [line items]    
Assets carried at fair value 396 207
Level II [member] | Money Markets and other short-term investment [member] | Financial assets at fair value through profit or loss, category [member]    
Disclosure of fair value measurement of assets and liabilities [line items]    
Assets carried at fair value   160
Level II [member] | Other investments at fair value [member] | Fair value through other comprehensive income [member]    
Disclosure of fair value measurement of assets and liabilities [line items]    
Assets carried at fair value 29 27
Level II [member] | Other investments at fair value [member] | Financial assets at fair value through profit or loss, category [member]    
Disclosure of fair value measurement of assets and liabilities [line items]    
Assets carried at fair value 2 716
Level II [member] | Derivatives [member] | Financial assets at fair value through profit or loss, category [member]    
Disclosure of fair value measurement of assets and liabilities [line items]    
Assets carried at fair value 621 464
Level II [member] | Investments - Policyholder Risk [Member] | Financial assets at fair value through profit or loss, category [member]    
Disclosure of fair value measurement of assets and liabilities [line items]    
Assets carried at fair value 21,218 125,710
Level II [member] | Investment contracts without DPF - Policyholder risk [member]    
Disclosure of fair value measurement of assets and liabilities [line items]    
Liabilities carried at fair value 28,269 85,161
Level II [member] | Derivatives [member]    
Disclosure of fair value measurement of assets and liabilities [line items]    
Liabilities carried at fair value 1,262 1,419
Level III [member]    
Disclosure of fair value measurement of assets and liabilities [line items]    
Assets carried at fair value 5,000 5,163
Level III [member] | Fair value through other comprehensive income [member]    
Disclosure of fair value measurement of assets and liabilities [line items]    
Assets carried at fair value 701 533
Level III [member] | Financial assets at fair value through profit or loss, category [member]    
Disclosure of fair value measurement of assets and liabilities [line items]    
Assets carried at fair value 4,299 4,630
Level III [member] | Shares [member] | Fair value through other comprehensive income [member]    
Disclosure of fair value measurement of assets and liabilities [line items]    
Assets carried at fair value 5 5
Level III [member] | Shares [member] | Financial assets at fair value through profit or loss, category [member]    
Disclosure of fair value measurement of assets and liabilities [line items]    
Assets carried at fair value 49 54
Level III [member] | Debt securities [member] | Fair value through other comprehensive income [member]    
Disclosure of fair value measurement of assets and liabilities [line items]    
Assets carried at fair value 695 528
Level III [member] | Debt securities [member] | Financial assets at fair value through profit or loss, category [member]    
Disclosure of fair value measurement of assets and liabilities [line items]    
Assets carried at fair value 127 110
Level III [member] | Money Markets and other short-term investment [member] | Fair value through other comprehensive income [member]    
Disclosure of fair value measurement of assets and liabilities [line items]    
Assets carried at fair value 1  
Level III [member] | Loans [member] | Financial assets at fair value through profit or loss, category [member]    
Disclosure of fair value measurement of assets and liabilities [line items]    
Assets carried at fair value 84 82
Level III [member] | Other investments at fair value [member] | Fair value through other comprehensive income [member]    
Disclosure of fair value measurement of assets and liabilities [line items]    
Assets carried at fair value   1
Level III [member] | Other investments at fair value [member] | Financial assets at fair value through profit or loss, category [member]    
Disclosure of fair value measurement of assets and liabilities [line items]    
Assets carried at fair value 3,944 3,987
Level III [member] | Derivatives [member] | Financial assets at fair value through profit or loss, category [member]    
Disclosure of fair value measurement of assets and liabilities [line items]    
Assets carried at fair value   8
Level III [member] | Investments - Policyholder Risk [Member] | Financial assets at fair value through profit or loss, category [member]    
Disclosure of fair value measurement of assets and liabilities [line items]    
Assets carried at fair value € 96 € 389