v3.25.2
Derivative Financial Instruments (Notional and Fair Value Amounts of Derivative Financial Instruments) (Detail) - USD ($)
$ in Millions
Jun. 30, 2025
Dec. 31, 2024
Derivative [Line Items]    
NOTIONAL VALUE $ 431,984.8 $ 393,391.8
Derivative Assets 4,066.5 5,358.5
GROSS AMOUNTS OFFSET IN THE BALANCE SHEET 3,175.5 1,910.4
Derivative Assets 891.0 3,448.1
LIABILITY 4,537.7 5,158.4
Less: Liability, Netting 2,380.7 4,199.6
Derivative Liabilities $ 2,157.0 $ 958.8
Derivative assets, location Other Assets Other Assets
Derivative liabilities, location Other Liabilities Other Liabilities
Derivatives Designated as Hedging under GAAP    
Derivative [Line Items]    
NOTIONAL VALUE $ 14,284.6 $ 15,137.7
Derivative Assets 242.4 426.7
LIABILITY 639.0 183.6
Derivatives Designated as Hedging under GAAP | Fair Value Hedges | Interest Rate Contracts    
Derivative [Line Items]    
NOTIONAL VALUE 9,748.3 9,706.3
Derivative Assets 242.4 189.4
LIABILITY 223.9 159.3
Derivatives Designated as Hedging under GAAP | Cash Flow Hedges | Foreign Exchange Contracts    
Derivative [Line Items]    
NOTIONAL VALUE 138.4 872.8
Derivative Assets 0.0 40.8
LIABILITY 7.7 0.0
Derivatives Designated as Hedging under GAAP | Net Investment Hedges | Foreign Exchange Contracts    
Derivative [Line Items]    
NOTIONAL VALUE 4,397.9 4,558.6
Derivative Assets 0.0 196.5
LIABILITY 407.4 24.3
Derivatives Not Designated as Hedging under GAAP | Fair Value Hedges    
Derivative [Line Items]    
NOTIONAL VALUE 417,700.2 378,254.1
Derivative Assets 3,824.1 4,931.8
LIABILITY 3,898.7 4,974.8
Non-Designated Risk Management Derivatives | Fair Value Hedges    
Derivative [Line Items]    
NOTIONAL VALUE 573.7 513.7
Derivative Assets 0.0 0.0
LIABILITY 22.8 27.2
Non-Designated Risk Management Derivatives | Fair Value Hedges | Foreign Exchange Contracts    
Derivative [Line Items]    
NOTIONAL VALUE 1.7 1.7
Derivative Assets 0.0 0.0
LIABILITY 0.0 0.0
Non-Designated Risk Management Derivatives | Fair Value Hedges | Other Financial Derivatives    
Derivative [Line Items]    
NOTIONAL VALUE 572.0 512.0
Derivative Assets 0.0 0.0
LIABILITY 22.8 27.2
Client-Related and Trading Derivatives | Fair Value Hedges    
Derivative [Line Items]    
NOTIONAL VALUE 417,126.5 377,740.4
Derivative Assets 3,824.1 4,931.8
LIABILITY 3,875.9 4,947.6
Client-Related and Trading Derivatives | Fair Value Hedges | Foreign Exchange Contracts    
Derivative [Line Items]    
NOTIONAL VALUE 402,917.6 362,658.7
Derivative Assets 3,697.1 4,760.0
LIABILITY 3,697.2 4,685.5
Client-Related and Trading Derivatives | Fair Value Hedges | Interest Rate Contracts    
Derivative [Line Items]    
NOTIONAL VALUE 14,208.9 15,081.7
Derivative Assets 127.0 171.8
LIABILITY $ 178.7 $ 262.1