v3.26.1
Discontinued operations - Disclosure Of Changes In Fair Value Measurement Assets And Liabilities For Disontinued Operations Explanatory (Detail) - EUR (€)
€ in Millions
 6 Months Ended 12 Months Ended
Jun. 30, 2026
Dec. 31, 2025
Changes in Financial Instruments Measured at Fair Value [Line Items]    
Ending balance € 337,725 € 317,233
Level 3 of fair value hierarchy [member] | Recurring fair value measurement [member]    
Changes in Financial Instruments Measured at Fair Value [Line Items]    
Total gains (losses) in income statement (147) (28)
Purchases 257 940
Sales (229) (573)
Settlements 53 90
Total unrealized gains and losses for the period (94) 26
FVPL [member] | Level 3 of fair value hierarchy [member] | Recurring fair value measurement [member]    
Changes in Financial Instruments Measured at Fair Value [Line Items]    
Total gains (losses) in income statement (151) (35)
Purchases 178 815
Sales (183) (491)
Settlements 3 5
Total unrealized gains and losses for the period (94) 26
FVPL [member] | Level 3 of fair value hierarchy [member] | Recurring fair value measurement [member] | Discontinued operations [member]    
Changes in Financial Instruments Measured at Fair Value [Line Items]    
Transfers to disposal groups 316  
Total gains (losses) in income statement [1] 2  
Purchases 38  
Sales (18)  
Settlements 0  
Net exchange difference 2  
Ending balance 340  
Total unrealized gains and losses for the period [2] 2  
FVPL [member] | Derivatives [member] | Level 3 of fair value hierarchy [member] | Recurring fair value measurement [member]    
Changes in Financial Instruments Measured at Fair Value [Line Items]    
Total gains (losses) in income statement 2  
Sales   (1)
Total unrealized gains and losses for the period   (1)
FVPL [member] | Derivatives [member] | Level 3 of fair value hierarchy [member] | Recurring fair value measurement [member] | Discontinued operations [member]    
Changes in Financial Instruments Measured at Fair Value [Line Items]    
Transfers to disposal groups 10  
Total gains (losses) in income statement [1] (1)  
Purchases 0  
Sales (1)  
Settlements 0  
Net exchange difference 0  
Ending balance 8  
Total unrealized gains and losses for the period [2] 1  
FVPL [member] | Investments - Policyholder risk [member] | Level 3 of fair value hierarchy [member] | Recurring fair value measurement [member]    
Changes in Financial Instruments Measured at Fair Value [Line Items]    
Total gains (losses) in income statement 4 (36)
Purchases 14 320
Sales (10) (38)
Total unrealized gains and losses for the period   € 1
FVPL [member] | Investments - Policyholder risk [member] | Level 3 of fair value hierarchy [member] | Recurring fair value measurement [member] | Discontinued operations [member]    
Changes in Financial Instruments Measured at Fair Value [Line Items]    
Transfers to disposal groups 307  
Total gains (losses) in income statement [1] 3  
Purchases 38  
Sales (17)  
Settlements 0  
Net exchange difference 2  
Ending balance 332  
Total unrealized gains and losses for the period [2] € 2  
[1] Includes impairments and movements related to fair value hedges. Gains and losses are recorded in the line item Results from financial transactions of the income statement.
[2] Total unrealized gains / (losses) for the period recorded in the P&L during which the financial instrument was in Level III.