v3.26.1
FVM - Movements of level 3 instruments - Assets (Detail) - USD ($)
$ in Millions
 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Dec. 31, 2025
Disclosure Of Fair Value Measurement Of Assets [Line Items]      
Total Level 3 assets $ 557,905   $ 492,557
Level 3      
Disclosure Of Fair Value Measurement Of Assets [Line Items]      
Total Level 3 assets 16,002   $ 14,538
Level 3 | of which: Equity instruments      
Disclosure Of Fair Value Measurement Of Assets [Line Items]      
Balance at the beginning of the period 2,200    
Balance at the end of the period 2,300    
Level 3 | of which: Corporate and municipal bonds      
Disclosure Of Fair Value Measurement Of Assets [Line Items]      
Balance at the beginning of the period 1,000    
Balance at the end of the period 1,300    
Level 3 | of which: Investment fund units      
Disclosure Of Fair Value Measurement Of Assets [Line Items]      
Balance at the beginning of the period 700    
Balance at the end of the period 700    
Level 3 | Financial assets at fair value held for trading      
Disclosure Of Fair Value Measurement Of Assets [Line Items]      
Balance at the beginning of the period 2,300 $ 3,100  
Total gains / (losses) included in comprehensive income - Net gains / (losses) included in income 0 0  
Total gains / (losses) included in comprehensive income - of which: related to Level 3 instruments held at the end of the reporting period 0 (100)  
Purchases 900 400  
Sales (700) (1,100)  
Issuances 1,000 1,100  
Settlements (400) (400)  
Transfers into Level 3 700 400  
Transfers out of Level 3 (200) (100)  
Foreign currency translation 0 100  
Balance at the end of the period 3,400 3,500  
Level 3 | Financial assets at fair value held for trading | of which: Equity instruments      
Disclosure Of Fair Value Measurement Of Assets [Line Items]      
Balance at the beginning of the period 200 100  
Total gains / (losses) included in comprehensive income - Net gains / (losses) included in income 0 0  
Total gains / (losses) included in comprehensive income - of which: related to Level 3 instruments held at the end of the reporting period 0 0  
Purchases 0 0  
Sales (300) (0)  
Issuances 0 0  
Settlements (0) (0)  
Transfers into Level 3 400 100  
Transfers out of Level 3 (0) (0)  
Foreign currency translation 0 0  
Balance at the end of the period 200 200  
Level 3 | Financial assets at fair value held for trading | of which: Corporate and municipal bonds      
Disclosure Of Fair Value Measurement Of Assets [Line Items]      
Balance at the beginning of the period 900 800  
Total gains / (losses) included in comprehensive income - Net gains / (losses) included in income 0 0  
Total gains / (losses) included in comprehensive income - of which: related to Level 3 instruments held at the end of the reporting period 0 0  
Purchases 400 300  
Sales (200) (400)  
Issuances 0 0  
Settlements (0) (0)  
Transfers into Level 3 200 100  
Transfers out of Level 3 (200) (100)  
Foreign currency translation 0 0  
Balance at the end of the period 1,100 800  
Level 3 | Financial assets at fair value held for trading | of which: Loans      
Disclosure Of Fair Value Measurement Of Assets [Line Items]      
Balance at the beginning of the period 1,100 1,800  
Total gains / (losses) included in comprehensive income - Net gains / (losses) included in income 0 100  
Total gains / (losses) included in comprehensive income - of which: related to Level 3 instruments held at the end of the reporting period 0 0  
Purchases 0 0  
Sales (300) (500)  
Issuances 1,000 1,100  
Settlements (400) (300)  
Transfers into Level 3 0 0  
Transfers out of Level 3 (0) (0)  
Foreign currency translation 0 0  
Balance at the end of the period 1,400 2,200  
Level 3 | Derivative financial instruments      
Disclosure Of Fair Value Measurement Of Assets [Line Items]      
Balance at the beginning of the period 3,200 2,800  
Total gains / (losses) included in comprehensive income - Net gains / (losses) included in income 200 0  
Total gains / (losses) included in comprehensive income - of which: related to Level 3 instruments held at the end of the reporting period 200 100  
Purchases 0 0  
Sales (0) (0)  
Issuances 700 1,300  
Settlements (800) (900)  
Transfers into Level 3 100 300  
Transfers out of Level 3 (700) (300)  
Foreign currency translation 0 0  
Balance at the end of the period 2,800 3,200  
Level 3 | Derivative financial instruments | of which: Interest rate      
Disclosure Of Fair Value Measurement Of Assets [Line Items]      
Balance at the beginning of the period 1,200 900  
Total gains / (losses) included in comprehensive income - Net gains / (losses) included in income 100 100  
Total gains / (losses) included in comprehensive income - of which: related to Level 3 instruments held at the end of the reporting period 100 100  
Purchases 0 0  
Sales (0) (0)  
Issuances 0 0  
Settlements (100) (200)  
Transfers into Level 3 0 100  
Transfers out of Level 3 (400) (0)  
Foreign currency translation 0 (100)  
Balance at the end of the period 800 900  
Level 3 | Derivative financial instruments | of which: Equity / index      
Disclosure Of Fair Value Measurement Of Assets [Line Items]      
Balance at the beginning of the period 1,400 1,100  
Total gains / (losses) included in comprehensive income - Net gains / (losses) included in income 200 (200)  
Total gains / (losses) included in comprehensive income - of which: related to Level 3 instruments held at the end of the reporting period 100 (200)  
Purchases 0 0  
Sales (0) (0)  
Issuances 600 700  
Settlements (700) (300)  
Transfers into Level 3 0 100  
Transfers out of Level 3 (300) (200)  
Foreign currency translation 0 0  
Balance at the end of the period 1,300 1,300  
Level 3 | Derivative financial instruments | of which: Credit      
Disclosure Of Fair Value Measurement Of Assets [Line Items]      
Balance at the beginning of the period 300 600  
Total gains / (losses) included in comprehensive income - Net gains / (losses) included in income (100) 100  
Total gains / (losses) included in comprehensive income - of which: related to Level 3 instruments held at the end of the reporting period 0 200  
Purchases 0 0  
Sales (0) (0)  
Issuances 100 500  
Settlements (0) (300)  
Transfers into Level 3 0 100  
Transfers out of Level 3 (0) (100)  
Foreign currency translation 0 0  
Balance at the end of the period 400 900  
Level 3 | Financial assets at fair value not held for trading      
Disclosure Of Fair Value Measurement Of Assets [Line Items]      
Balance at the beginning of the period 8,900 8,700  
Total gains / (losses) included in comprehensive income - Net gains / (losses) included in income 700 700  
Total gains / (losses) included in comprehensive income - of which: related to Level 3 instruments held at the end of the reporting period 700 600  
Purchases 100 100  
Sales (100) (300)  
Issuances 1,400 700  
Settlements (1,000) (800)  
Transfers into Level 3 0 100  
Transfers out of Level 3 (200) (100)  
Foreign currency translation 0 200  
Balance at the end of the period 9,700 9,300  
Level 3 | Financial assets at fair value not held for trading | of which: Equity instruments      
Disclosure Of Fair Value Measurement Of Assets [Line Items]      
Balance at the beginning of the period 2,100 2,900  
Total gains / (losses) included in comprehensive income - Net gains / (losses) included in income 0 100  
Total gains / (losses) included in comprehensive income - of which: related to Level 3 instruments held at the end of the reporting period 0 100  
Purchases 0 100  
Sales (0) (100)  
Issuances 0 0  
Settlements (0) (0)  
Transfers into Level 3 0 0  
Transfers out of Level 3 (0) (0)  
Foreign currency translation 0 100  
Balance at the end of the period 2,100 3,100  
Level 3 | Financial assets at fair value not held for trading | of which: Loans      
Disclosure Of Fair Value Measurement Of Assets [Line Items]      
Balance at the beginning of the period 4,200 3,200  
Total gains / (losses) included in comprehensive income - Net gains / (losses) included in income 700 700  
Total gains / (losses) included in comprehensive income - of which: related to Level 3 instruments held at the end of the reporting period 700 700  
Purchases 0 0  
Sales (0) (0)  
Issuances 1,200 500  
Settlements (500) (700)  
Transfers into Level 3 0 0  
Transfers out of Level 3 (200) (0)  
Foreign currency translation 0 100  
Balance at the end of the period 5,400 3,700  
Level 3 | Financial assets at fair value not held for trading | of which: Auction rate securities      
Disclosure Of Fair Value Measurement Of Assets [Line Items]      
Balance at the beginning of the period 200 200  
Total gains / (losses) included in comprehensive income - Net gains / (losses) included in income 0 0  
Total gains / (losses) included in comprehensive income - of which: related to Level 3 instruments held at the end of the reporting period 0 0  
Purchases 0 0  
Sales (0) (0)  
Issuances 0 0  
Settlements (200) (0)  
Transfers into Level 3 0 0  
Transfers out of Level 3 (0) (0)  
Foreign currency translation 0 0  
Balance at the end of the period 0 200  
Level 3 | Financial assets at fair value not held for trading | of which: Investment fund units      
Disclosure Of Fair Value Measurement Of Assets [Line Items]      
Balance at the beginning of the period 700 700  
Total gains / (losses) included in comprehensive income - Net gains / (losses) included in income 0 0  
Total gains / (losses) included in comprehensive income - of which: related to Level 3 instruments held at the end of the reporting period 0 0  
Purchases 0 0  
Sales (100) (100)  
Issuances 0 0  
Settlements (0) (0)  
Transfers into Level 3 0 0  
Transfers out of Level 3 (0) (0)  
Foreign currency translation 0 0  
Balance at the end of the period 600 600  
Level 3 | Financial assets at fair value not held for trading | of which: Asset-backed securities      
Disclosure Of Fair Value Measurement Of Assets [Line Items]      
Balance at the beginning of the period 500 600  
Total gains / (losses) included in comprehensive income - Net gains / (losses) included in income 0 0  
Total gains / (losses) included in comprehensive income - of which: related to Level 3 instruments held at the end of the reporting period 0 0  
Purchases 0 0  
Sales (0) (100)  
Issuances 0 0  
Settlements (0) (0)  
Transfers into Level 3 0 0  
Transfers out of Level 3 (0) (0)  
Foreign currency translation 0 0  
Balance at the end of the period $ 400 $ 500