v3.25.2
FVM - Movements of level 3 instruments - Assets (Detail) - USD ($)
$ in Millions
 6 Months Ended
Jun. 30, 2025
Jun. 30, 2024
Mar. 31, 2025
Dec. 31, 2024
Disclosure Of Fair Value Measurement Of Assets [Line Items]        
Total Level 3 assets $ 492,426   $ 445,263 $ 475,568
Level 3        
Disclosure Of Fair Value Measurement Of Assets [Line Items]        
Total Level 3 assets 15,944   $ 15,400 $ 14,732
Level 3 | Equity instruments        
Disclosure Of Fair Value Measurement Of Assets [Line Items]        
Balance at the beginning of the period 3,000      
Balance at the end of the period 3,200      
Level 3 | 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 800      
Level 3 | Investment fund units        
Disclosure Of Fair Value Measurement Of Assets [Line Items]        
Balance at the beginning of the period 800      
Balance at the end of the period 700      
Level 3 | Asset-backed securities        
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 3,100 $ 22,600    
Total gains / (losses) included in comprehensive income - Net gains / (losses) included in income 0 300    
Total gains / (losses) included in comprehensive income - of which: related to Level 3 instruments held at the end of the reporting period (100) (300)    
Purchases 400 900    
Sales (1,100) (11,600)    
Issuances 1,100 800    
Settlements (400) (5,700)    
Transfers into Level 3 400 1,600    
Transfers out of Level 3 (100) (700)    
Foreign currency translation 100 (100)    
Balance at the end of the period 3,500 8,000    
Level 3 | Financial assets at fair value held for trading | Equity instruments        
Disclosure Of Fair Value Measurement Of Assets [Line Items]        
Balance at the beginning of the period 100 300    
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 (0) (0)    
Transfers into Level 3 100 0    
Transfers out of Level 3 (0) (100)    
Foreign currency translation 0 0    
Balance at the end of the period 200 200    
Level 3 | Financial assets at fair value held for trading | Corporate and municipal bonds        
Disclosure Of Fair Value Measurement Of Assets [Line Items]        
Balance at the beginning of the period 800 1,300    
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 300 300    
Sales (400) (500)    
Issuances 0 0    
Settlements (0) (0)    
Transfers into Level 3 100 0    
Transfers out of Level 3 (100) (100)    
Foreign currency translation 0 0    
Balance at the end of the period 800 900    
Level 3 | Financial assets at fair value held for trading | Loans        
Disclosure Of Fair Value Measurement Of Assets [Line Items]        
Balance at the beginning of the period 1,800 19,600    
Total gains / (losses) included in comprehensive income - Net gains / (losses) included in income 100 500    
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 0 400    
Sales (500) (9,900)    
Issuances 1,100 800    
Settlements (300) (5,700)    
Transfers into Level 3 0 1,400    
Transfers out of Level 3 (0) (600)    
Foreign currency translation 0 (100)    
Balance at the end of the period 2,200 6,400    
Level 3 | Derivative financial instruments        
Disclosure Of Fair Value Measurement Of Assets [Line Items]        
Balance at the beginning of the period 2,800 2,600    
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 100 0    
Purchases 0 0    
Sales (0) (0)    
Issuances 1,300 600    
Settlements (900) (500)    
Transfers into Level 3 300 300    
Transfers out of Level 3 (300) (600)    
Foreign currency translation 0 0    
Balance at the end of the period 3,200 2,300    
Level 3 | Derivative financial instruments | Interest rate        
Disclosure Of Fair Value Measurement Of Assets [Line Items]        
Balance at the beginning of the period 900 400    
Total gains / (losses) included in comprehensive income - Net gains / (losses) included in income 100 0    
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 (200) (100)    
Transfers into Level 3 100 100    
Transfers out of Level 3 (0) (0)    
Foreign currency translation (100) 0    
Balance at the end of the period 900 400    
Level 3 | Derivative financial instruments | Equity / index        
Disclosure Of Fair Value Measurement Of Assets [Line Items]        
Balance at the beginning of the period 1,100 1,300    
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) 0    
Purchases 0 0    
Sales (0) (0)    
Issuances 700 500    
Settlements (300) (200)    
Transfers into Level 3 100 100    
Transfers out of Level 3 (200) (400)    
Foreign currency translation 0 0    
Balance at the end of the period 1,300 1,200    
Level 3 | Derivative financial instruments | Credit        
Disclosure Of Fair Value Measurement Of Assets [Line Items]        
Balance at the beginning of the period 600 500    
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 200 0    
Purchases 0 0    
Sales (0) (0)    
Issuances 500 100    
Settlements (300) (100)    
Transfers into Level 3 100 100    
Transfers out of Level 3 (100) (0)    
Foreign currency translation 0 0    
Balance at the end of the period 900 500    
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 8,700 8,400    
Total gains / (losses) included in comprehensive income - Net gains / (losses) included in income 700 (200)    
Total gains / (losses) included in comprehensive income - of which: related to Level 3 instruments held at the end of the reporting period 600 (300)    
Purchases 100 300    
Sales (300) (200)    
Issuances 700 1,100    
Settlements (800) (1,700)    
Transfers into Level 3 100 500    
Transfers out of Level 3 (100) (200)    
Foreign currency translation 200 (100)    
Balance at the end of the period 9,300 7,900    
Level 3 | Financial assets at fair value not held for trading | Equity instruments        
Disclosure Of Fair Value Measurement Of Assets [Line Items]        
Balance at the beginning of the period 2,900 3,100    
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 100 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 100 (100)    
Balance at the end of the period 3,100 2,900    
Level 3 | Financial assets at fair value not held for trading | Loans        
Disclosure Of Fair Value Measurement Of Assets [Line Items]        
Balance at the beginning of the period 3,200 2,300    
Total gains / (losses) included in comprehensive income - Net gains / (losses) included in income 700 (100)    
Total gains / (losses) included in comprehensive income - of which: related to Level 3 instruments held at the end of the reporting period 700 (100)    
Purchases 0 200    
Sales (0) (0)    
Issuances 500 700    
Settlements (700) (300)    
Transfers into Level 3 0 0    
Transfers out of Level 3 (0) (100)    
Foreign currency translation 100 (100)    
Balance at the end of the period 3,700 2,600    
Level 3 | Financial assets at fair value not held for trading | Auction rate securities        
Disclosure Of Fair Value Measurement Of Assets [Line Items]        
Balance at the beginning of the period 200 1,200    
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 (0) (1,100)    
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 200 200    
Level 3 | Financial assets at fair value not held for trading | 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 0 100    
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 600 700    
Level 3 | Financial assets at fair value not held for trading | Asset-backed securities        
Disclosure Of Fair Value Measurement Of Assets [Line Items]        
Balance at the beginning of the period 600 200    
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 (100) (0)    
Issuances 0 0    
Settlements (0) (0)    
Transfers into Level 3 0 400    
Transfers out of Level 3 (0) (0)    
Foreign currency translation 0 0    
Balance at the end of the period $ 500 $ 500