v3.26.1
FVM - Level 3 instruments: Valuation techniques and inputs (Detail) - Level 3
$ in Billions
Jun. 30, 2026
USD ($)
Dec. 31, 2025
USD ($)
Corporate and municipal bonds    
Disclosure Of Fair Value Measurement [Line Items]    
Financial assets measured at fair value $ 1.3 $ 1.0
Financial liabilities measured at fair value $ 0.0 $ 0.0
Corporate and municipal bonds | Relative value to market comparable | Bond price equivalent | low    
Disclosure Of Fair Value Measurement [Line Items]    
Significant unobservable input(s) 0.09 0.11
Corporate and municipal bonds | Relative value to market comparable | Bond price equivalent | high    
Disclosure Of Fair Value Measurement [Line Items]    
Significant unobservable input(s) 1.03 1.04
Corporate and municipal bonds | Relative value to market comparable | Bond price equivalent | weighted average    
Disclosure Of Fair Value Measurement [Line Items]    
Significant unobservable input(s) 0.93 0.80
Loans at fair value (held for trading and not held for trading) and guarantees    
Disclosure Of Fair Value Measurement [Line Items]    
Financial assets measured at fair value $ 6.9 $ 5.6
Financial liabilities measured at fair value $ 0.0 $ 0.0
Loans at fair value (held for trading and not held for trading) and guarantees | Relative value to market comparable | Loan price equivalent | low    
Disclosure Of Fair Value Measurement [Line Items]    
Significant unobservable input(s) 0.04 0.19
Loans at fair value (held for trading and not held for trading) and guarantees | Relative value to market comparable | Loan price equivalent | high    
Disclosure Of Fair Value Measurement [Line Items]    
Significant unobservable input(s) 1 1.01
Loans at fair value (held for trading and not held for trading) and guarantees | Relative value to market comparable | Loan price equivalent | weighted average    
Disclosure Of Fair Value Measurement [Line Items]    
Significant unobservable input(s) 0.96 0.87
Loans at fair value (held for trading and not held for trading) and guarantees | Discounted expected cash flows | Credit spread | low    
Disclosure Of Fair Value Measurement [Line Items]    
Significant unobservable input(s) 0.0275 0.0233
Loans at fair value (held for trading and not held for trading) and guarantees | Discounted expected cash flows | Credit spread | high    
Disclosure Of Fair Value Measurement [Line Items]    
Significant unobservable input(s) 0.0275 0.0277
Loans at fair value (held for trading and not held for trading) and guarantees | Discounted expected cash flows | Credit spread | weighted average    
Disclosure Of Fair Value Measurement [Line Items]    
Significant unobservable input(s) 0.0275 0.0277
Loans at fair value (held for trading and not held for trading) and guarantees | Market comparable and securitization model | Credit spread | low    
Disclosure Of Fair Value Measurement [Line Items]    
Significant unobservable input(s) 0.0075 0.0085
Loans at fair value (held for trading and not held for trading) and guarantees | Market comparable and securitization model | Credit spread | high    
Disclosure Of Fair Value Measurement [Line Items]    
Significant unobservable input(s) 0.1915 0.1965
Loans at fair value (held for trading and not held for trading) and guarantees | Market comparable and securitization model | Credit spread | weighted average    
Disclosure Of Fair Value Measurement [Line Items]    
Significant unobservable input(s) 0.0248 0.0323
Investment fund units    
Disclosure Of Fair Value Measurement [Line Items]    
Financial assets measured at fair value $ 0.7 $ 0.7
Financial liabilities measured at fair value 0.0 0.0
Equity instruments    
Disclosure Of Fair Value Measurement [Line Items]    
Financial assets measured at fair value 2.3 2.2
Financial liabilities measured at fair value 0.0 0.1
Securities financing transactions    
Disclosure Of Fair Value Measurement [Line Items]    
Financial assets measured at fair value 1.0 0.9
Securities financing transactions | At fair value    
Disclosure Of Fair Value Measurement [Line Items]    
Other financial liabilities $ 0.4 $ 0.5
Securities financing transactions | Discounted expected cash flows | Funding spread | low    
Disclosure Of Fair Value Measurement [Line Items]    
Significant unobservable input(s) 0.0095 0.0095
Securities financing transactions | Discounted expected cash flows | Funding spread | high    
Disclosure Of Fair Value Measurement [Line Items]    
Significant unobservable input(s) 0.0181 0.0166
Debt issued designated at fair value and Other financial liabilities designated at fair value | At fair value    
Disclosure Of Fair Value Measurement [Line Items]    
Other financial liabilities $ 13.3 $ 13.9
Interest rate    
Disclosure Of Fair Value Measurement [Line Items]    
Financial assets measured at fair value 0.8 1.2
Financial liabilities measured at fair value $ 0.3 $ 0.3
Interest rate | Option model | Volatility of interest rates | low    
Disclosure Of Fair Value Measurement [Line Items]    
Significant unobservable input(s) 0.0061 0.0061
Interest rate | Option model | Volatility of interest rates | high    
Disclosure Of Fair Value Measurement [Line Items]    
Significant unobservable input(s) 0.0080 0.0085
Credit    
Disclosure Of Fair Value Measurement [Line Items]    
Financial assets measured at fair value $ 0.4 $ 0.3
Financial liabilities measured at fair value $ 0.5 $ 0.3
Credit | Discounted expected cash flows | Credit spread | low    
Disclosure Of Fair Value Measurement [Line Items]    
Significant unobservable input(s) 0.0004 0.0003
Credit | Discounted expected cash flows | Credit spread | high    
Disclosure Of Fair Value Measurement [Line Items]    
Significant unobservable input(s) 0.1040 0.1040
Credit | Discounted expected cash flows | Recovery rates | low    
Disclosure Of Fair Value Measurement [Line Items]    
Significant unobservable input(s) 0.04 0.04
Credit | Discounted expected cash flows | Recovery rates | high    
Disclosure Of Fair Value Measurement [Line Items]    
Significant unobservable input(s) 0.60 0.60
Credit | Option model | Recovery rates | low    
Disclosure Of Fair Value Measurement [Line Items]    
Significant unobservable input(s) 0 0
Credit | Option model | Recovery rates | high    
Disclosure Of Fair Value Measurement [Line Items]    
Significant unobservable input(s) 0.40 0.40
Equity / index    
Disclosure Of Fair Value Measurement [Line Items]    
Financial assets measured at fair value $ 1.3 $ 1.4
Financial liabilities measured at fair value $ 4.4 $ 4.2
Equity / index | Option model | Equity dividend yields | low    
Disclosure Of Fair Value Measurement [Line Items]    
Significant unobservable input(s) 0 0
Equity / index | Option model | Equity dividend yields | high    
Disclosure Of Fair Value Measurement [Line Items]    
Significant unobservable input(s) 0.09 0.11
Equity / index | Option model | Volatility of equity stocks, equity and other indices | low    
Disclosure Of Fair Value Measurement [Line Items]    
Significant unobservable input(s) 0.04 0.03
Equity / index | Option model | Volatility of equity stocks, equity and other indices | high    
Disclosure Of Fair Value Measurement [Line Items]    
Significant unobservable input(s) 1.95 1.04
Equity / index | Option model | Equity-to-FX correlation | low    
Disclosure Of Fair Value Measurement [Line Items]    
Significant unobservable input(s) (0.65) (0.65)
Equity / index | Option model | Equity-to-FX correlation | high    
Disclosure Of Fair Value Measurement [Line Items]    
Significant unobservable input(s) 0.70 0.70
Equity / index | Option model | Equity-to-equity correlation | low    
Disclosure Of Fair Value Measurement [Line Items]    
Significant unobservable input(s) 0.13 (0.10)
Equity / index | Option model | Equity-to-equity correlation | high    
Disclosure Of Fair Value Measurement [Line Items]    
Significant unobservable input(s) 1 1
Loan commitments measured at FVTPL    
Disclosure Of Fair Value Measurement [Line Items]    
Financial liabilities measured at fair value $ 0.0 $ 0.0
Loan commitments measured at FVTPL | Relative value to market comparable | Loan price equivalent | low    
Disclosure Of Fair Value Measurement [Line Items]    
Significant unobservable input(s) 0.66 0.80
Loan commitments measured at FVTPL | Relative value to market comparable | Loan price equivalent | high    
Disclosure Of Fair Value Measurement [Line Items]    
Significant unobservable input(s) 1 1