v3.26.1
Segment Information - Summary of Investments (Detail) - EUR (€)
€ in Millions
Jun. 30, 2026
Dec. 31, 2025
Disclosure of summarized investment per segment [line items]    
Total investments on balance sheet € 167,187 € 285,141
Off-balance sheet investments third parties 513,475 606,437
Total revenue-generating investments 680,662 891,578
Investments in real estate 53 479
Investments in joint ventures 1,702 1,566
Investments in associates 2,761 2,638
Financial assets measured at amortized cost 9,522 9,719
Assets held for sale 138,246  
Other assets 27,830 [1] 27,888 [2]
Total assets 337,725 317,233
Backing insurance contracts without direct participation [member]    
Disclosure of summarized investment per segment [line items]    
Financial assets measured at FVOCI 43,506 41,109
Financial assets measured at FVPL 6,419 7,845
Non-insurance related assets [member]    
Disclosure of summarized investment per segment [line items]    
Financial assets measured at FVOCI 9,034 8,648
Financial assets measured at FVPL 29,394 86,320
Backing direct participation insurance contracts [member]    
Disclosure of summarized investment per segment [line items]    
Financial assets measured at FVPL 69,258 109,580
Backing direct participation investment contracts [member]    
Disclosure of summarized investment per segment [line items]    
Financial assets measured at FVPL   21,441
Shares [member]    
Disclosure of summarized investment per segment [line items]    
Investments 282 15,595
Debt securities [member]    
Disclosure of summarized investment per segment [line items]    
Investments 52,491 56,202
Unconsolidated investment funds [member]    
Disclosure of summarized investment per segment [line items]    
Investments 97,495 190,671
Loans [member]    
Disclosure of summarized investment per segment [line items]    
Investments 9,571 11,481
Other financial asset [member]    
Disclosure of summarized investment per segment [line items]    
Investments 7,294 10,713
Investments in real estate [member]    
Disclosure of summarized investment per segment [line items]    
Investments 53 479
Americas [member]    
Disclosure of summarized investment per segment [line items]    
Total investments on balance sheet 165,228 158,284
Off-balance sheet investments third parties 218,372 220,501
Total revenue-generating investments 383,599 378,786
Investments in real estate 35 24
Investments in associates 80 78
Financial assets measured at amortized cost 9,474 9,671
Other assets 25,072 [1] 23,859 [2]
Total assets 190,380 182,221
Americas [member] | Backing insurance contracts without direct participation [member]    
Disclosure of summarized investment per segment [line items]    
Financial assets measured at FVOCI 42,305 39,952
Financial assets measured at FVPL 6,376 6,811
Americas [member] | Non-insurance related assets [member]    
Disclosure of summarized investment per segment [line items]    
Financial assets measured at FVOCI 8,955 8,540
Financial assets measured at FVPL 29,099 27,540
Americas [member] | Backing direct participation insurance contracts [member]    
Disclosure of summarized investment per segment [line items]    
Financial assets measured at FVPL 68,985 65,746
Americas [member] | Shares [member]    
Disclosure of summarized investment per segment [line items]    
Investments 212 211
Americas [member] | Debt securities [member]    
Disclosure of summarized investment per segment [line items]    
Investments 51,233 48,104
Americas [member] | Unconsolidated investment funds [member]    
Disclosure of summarized investment per segment [line items]    
Investments 97,254 92,292
Americas [member] | Loans [member]    
Disclosure of summarized investment per segment [line items]    
Investments 9,557 9,753
Americas [member] | Other financial asset [member]    
Disclosure of summarized investment per segment [line items]    
Investments 6,937 7,900
Americas [member] | Investments in real estate [member]    
Disclosure of summarized investment per segment [line items]    
Investments 35 24
United Kingdom [member]    
Disclosure of summarized investment per segment [line items]    
Total investments on balance sheet   125,128
Off-balance sheet investments third parties   158,105
Total revenue-generating investments   283,233
Investments in real estate   437
Assets held for sale 138,246  
Other assets 14 [1] 1,795 [2]
Total assets 138,260 126,923
United Kingdom [member] | Backing insurance contracts without direct participation [member]    
Disclosure of summarized investment per segment [line items]    
Financial assets measured at FVPL   990
United Kingdom [member] | Non-insurance related assets [member]    
Disclosure of summarized investment per segment [line items]    
Financial assets measured at FVPL   58,668
United Kingdom [member] | Backing direct participation insurance contracts [member]    
Disclosure of summarized investment per segment [line items]    
Financial assets measured at FVPL   43,592
United Kingdom [member] | Backing direct participation investment contracts [member]    
Disclosure of summarized investment per segment [line items]    
Financial assets measured at FVPL   21,441
United Kingdom [member] | Shares [member]    
Disclosure of summarized investment per segment [line items]    
Investments   15,315
United Kingdom [member] | Debt securities [member]    
Disclosure of summarized investment per segment [line items]    
Investments   6,871
United Kingdom [member] | Unconsolidated investment funds [member]    
Disclosure of summarized investment per segment [line items]    
Investments   98,164
United Kingdom [member] | Loans [member]    
Disclosure of summarized investment per segment [line items]    
Investments   1,714
United Kingdom [member] | Other financial asset [member]    
Disclosure of summarized investment per segment [line items]    
Investments   2,627
United Kingdom [member] | Investments in real estate [member]    
Disclosure of summarized investment per segment [line items]    
Investments   437
International [Member]    
Disclosure of summarized investment per segment [line items]    
Total investments on balance sheet 1,559 1,487
Off-balance sheet investments third parties 8,444 4,602
Total revenue-generating investments 10,003 6,089
Investments in real estate 18 19
Investments in joint ventures 1,140 1,065
Financial assets measured at amortized cost 1 1
Other assets 4,406 [1] 4,416 [2]
Total assets 7,106 6,968
International [Member] | Backing insurance contracts without direct participation [member]    
Disclosure of summarized investment per segment [line items]    
Financial assets measured at FVOCI 1,202 1,158
Financial assets measured at FVPL 43 43
International [Member] | Non-insurance related assets [member]    
Disclosure of summarized investment per segment [line items]    
Financial assets measured at FVOCI 1 7
Financial assets measured at FVPL 20 18
International [Member] | Backing direct participation insurance contracts [member]    
Disclosure of summarized investment per segment [line items]    
Financial assets measured at FVPL 273 243
International [Member] | Shares [member]    
Disclosure of summarized investment per segment [line items]    
Investments 60 60
International [Member] | Debt securities [member]    
Disclosure of summarized investment per segment [line items]    
Investments 1,162 1,125
International [Member] | Unconsolidated investment funds [member]    
Disclosure of summarized investment per segment [line items]    
Investments 241 215
International [Member] | Loans [member]    
Disclosure of summarized investment per segment [line items]    
Investments 3 3
International [Member] | Other financial asset [member]    
Disclosure of summarized investment per segment [line items]    
Investments 75 67
International [Member] | Investments in real estate [member]    
Disclosure of summarized investment per segment [line items]    
Investments 18 19
Asset management [member]    
Disclosure of summarized investment per segment [line items]    
Total investments on balance sheet 389 230
Off-balance sheet investments third parties 286,659 223,228
Total revenue-generating investments 287,048 223,459
Investments in joint ventures 562 502
Investments in associates 284 296
Financial assets measured at amortized cost 36 36
Other assets 561 [1] 523 [2]
Total assets 1,796 1,551
Asset management [member] | Non-insurance related assets [member]    
Disclosure of summarized investment per segment [line items]    
Financial assets measured at FVOCI 79 100
Financial assets measured at FVPL 275 94
Asset management [member] | Shares [member]    
Disclosure of summarized investment per segment [line items]    
Investments 10 9
Asset management [member] | Debt securities [member]    
Disclosure of summarized investment per segment [line items]    
Investments 96 102
Asset management [member] | Other financial asset [member]    
Disclosure of summarized investment per segment [line items]    
Investments 283 119
Holding and other activities [member]    
Disclosure of summarized investment per segment [line items]    
Total investments on balance sheet 11 11
Total revenue-generating investments 11 11
Investments in associates 2,397 2,264
Financial assets measured at amortized cost 11 11
Other assets 10,759 [1] 10,485 [2]
Total assets 13,168 12,760
Holding and other activities [member] | Loans [member]    
Disclosure of summarized investment per segment [line items]    
Investments € 11 € 11
[1] Other assets total eliminates intercompany transactions of EUR 12,984 million.
[2] Other assets total eliminates intercompany transactions of EUR 13,190 million.