v3.26.1
Fair Value - Disclosures of Changes in Level 3 Assets (Detail) - EUR (€)
€ in Millions
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Changes in fair value measurement assets and liabilities [Line Items]    
Beginning balance € 327,390  
Ending balance 317,233 € 327,390
Beginning balance 318,077  
Level III [member]    
Changes in fair value measurement assets and liabilities [Line Items]    
Beginning balance 6,436  
Disposal of a business (14)  
Total gains /losses in income statement (10)  
Total gains /losses in OCI 6  
Purchases 952  
Sales (614)  
Settlements (91)  
Net exchange difference (706)  
Transfers from levels I and II 93  
Transfers to levels I and II (355)  
Ending balance 5,699 6,436
Total unrealized gains and (losses) for the period recorded in the P&L for instruments held 57  
Beginning balance   6
Total gains /losses in income statement   (6)
Level III [member] | Recurring fair value measurement [member]    
Changes in fair value measurement assets and liabilities [Line Items]    
Beginning balance 6,436 5,849
Total gains /losses in income statement   (174)
Total gains /losses in OCI   (37)
Purchases   857
Sales   (638)
Settlements   (45)
Net exchange difference   385
Transfers from levels I and II   354
Transfers to levels I and II   (114)
Ending balance   6,436
Total unrealized gains and (losses) for the period recorded in the P&L for instruments held   (169)
Level III [member] | Recurring fair value measurement [member] | Derivatives [member]    
Changes in fair value measurement assets and liabilities [Line Items]    
Beginning balance   6
Total gains /losses in income statement   (6)
Level III [member] | Recurring fair value measurement [member] | Real estate held for own use [member]    
Changes in fair value measurement assets and liabilities [Line Items]    
Beginning balance 66 64
Total gains /losses in income statement   (1)
Total gains /losses in OCI 1 (1)
Purchases (1)  
Sales (1) (1)
Net exchange difference (7) 4
Reclassification (1)  
Ending balance 56 66
Total unrealized gains and (losses) for the period recorded in the P&L for instruments held   (1)
Level III [member] | Recurring fair value measurement [member] | Fair value through other comprehensive income [member]    
Changes in fair value measurement assets and liabilities [Line Items]    
Beginning balance 803 530
Total gains /losses in income statement 7 9
Total gains /losses in OCI 5 (36)
Purchases 125 218
Sales (83) (126)
Settlements (86) (41)
Net exchange difference (84) 44
Transfers from levels I and II 71 301
Transfers to levels I and II (226) (96)
Ending balance 533 803
Level III [member] | Recurring fair value measurement [member] | Fair value through other comprehensive income [member] | Shares [member]    
Changes in fair value measurement assets and liabilities [Line Items]    
Beginning balance 4 4
Total gains /losses in income statement 0  
Ending balance 5 4
Level III [member] | Recurring fair value measurement [member] | Fair value through other comprehensive income [member] | Debt securities [member]    
Changes in fair value measurement assets and liabilities [Line Items]    
Beginning balance 799 516
Total gains /losses in income statement 7 9
Total gains /losses in OCI 5 (27)
Purchases 124 218
Sales (82) (126)
Settlements (86) (41)
Net exchange difference (84) 44
Transfers from levels I and II 71 301
Transfers to levels I and II (226) (96)
Ending balance 528 799
Level III [member] | Recurring fair value measurement [member] | Fair value through other comprehensive income [member] | Money markets and other short-term investments [Member]    
Changes in fair value measurement assets and liabilities [Line Items]    
Beginning balance   9
Total gains /losses in income statement 0  
Total gains /losses in OCI (1) (9)
Purchases 1  
Ending balance 1  
Level III [member] | Recurring fair value measurement [member] | Financial assets at fair value through profit or loss, mandatorily measured at fair value, category [member]    
Changes in fair value measurement assets and liabilities [Line Items]    
Beginning balance 5,567 5,255
Disposal of a business (14)  
Total gains /losses in income statement (17) (183)
Purchases 827 638
Sales (530) (511)
Settlements (5) (5)
Net exchange difference (614) 338
Reclassification 1  
Transfers from levels I and II 23 53
Transfers to levels I and II (129) (18)
Ending balance 5,109 5,567
Total unrealized gains and (losses) for the period recorded in the P&L for instruments held 57 (169)
Level III [member] | Recurring fair value measurement [member] | Financial assets at fair value through profit or loss, mandatorily measured at fair value, category [member] | Shares [member]    
Changes in fair value measurement assets and liabilities [Line Items]    
Beginning balance 86 94
Total gains /losses in income statement 7 (3)
Purchases 17 16
Sales (46) (27)
Net exchange difference (9) 6
Ending balance 54 86
Total unrealized gains and (losses) for the period recorded in the P&L for instruments held 7 (5)
Level III [member] | Recurring fair value measurement [member] | Financial assets at fair value through profit or loss, mandatorily measured at fair value, category [member] | Debt securities [member]    
Changes in fair value measurement assets and liabilities [Line Items]    
Beginning balance 107 86
Total gains /losses in income statement   (19)
Purchases 2 18
Sales (1) (14)
Settlements (5) (5)
Net exchange difference (13) 6
Transfers from levels I and II 23 53
Transfers to levels I and II (2) (18)
Ending balance 110 107
Total unrealized gains and (losses) for the period recorded in the P&L for instruments held   (18)
Level III [member] | Recurring fair value measurement [member] | Financial assets at fair value through profit or loss, mandatorily measured at fair value, category [member] | Other investments [member]    
Changes in fair value measurement assets and liabilities [Line Items]    
Beginning balance 4,457 4,237
Total gains /losses in income statement (9) (175)
Purchases 463 505
Sales (400) (323)
Net exchange difference (525) 280
Reclassification   (68)
Ending balance 3,987 4,457
Total unrealized gains and (losses) for the period recorded in the P&L for instruments held 16 (206)
Level III [member] | Recurring fair value measurement [member] | Financial assets at fair value through profit or loss, mandatorily measured at fair value, category [member] | Loans [member]    
Changes in fair value measurement assets and liabilities [Line Items]    
Beginning balance 82  
Total gains /losses in income statement 4  
Purchases 12 12
Sales (5) (1)
Net exchange difference (10) 4
Reclassification   68
Ending balance 82 82
Total unrealized gains and (losses) for the period recorded in the P&L for instruments held 3  
Level III [member] | Recurring fair value measurement [member] | Financial assets at fair value through profit or loss, mandatorily measured at fair value, category [member] | Derivative [member]    
Changes in fair value measurement assets and liabilities [Line Items]    
Beginning balance 9 8
Total gains /losses in income statement 0 1
Sales (1) (1)
Net exchange difference 0  
Ending balance 8 9
Total unrealized gains and (losses) for the period recorded in the P&L for instruments held (1) 1
Level III [member] | Recurring fair value measurement [member] | Financial assets at fair value through profit or loss, mandatorily measured at fair value, category [member] | Investments in real estate [member]    
Changes in fair value measurement assets and liabilities [Line Items]    
Beginning balance 57 55
Total gains /losses in income statement 10 1
Purchases   1
Sales (23) (2)
Net exchange difference (4) 3
Reclassification 1  
Ending balance 42 57
Total unrealized gains and (losses) for the period recorded in the P&L for instruments held 13  
Level III [member] | Recurring fair value measurement [member] | Financial assets at fair value through profit or loss, mandatorily measured at fair value, category [member] | Investments in real estate for policyholders [member]    
Changes in fair value measurement assets and liabilities [Line Items]    
Beginning balance 457 433
Total gains /losses in income statement 8 9
Purchases 12 26
Sales (16) (32)
Net exchange difference (24) 21
Ending balance 437 457
Total unrealized gains and (losses) for the period recorded in the P&L for instruments held 19 59
Level III [member] | Recurring fair value measurement [member] | Financial assets at fair value through profit or loss, mandatorily measured at fair value, category [member] | Investments - Policyholder risk [member]    
Changes in fair value measurement assets and liabilities [Line Items]    
Beginning balance 312 342
Disposal of a business (14)  
Total gains /losses in income statement (36) 3
Purchases 320 62
Sales (38) (112)
Net exchange difference (28) 18
Transfers to levels I and II (127)  
Ending balance 389 312
Total unrealized gains and (losses) for the period recorded in the P&L for instruments held € 1 € 1