Derivatives - Derivatives Associated with Interest Rate Risk Management Activities (Details) - USD ($) $ in Millions	Jun. 30, 2025	Dec. 31, 2024
Customer interest rate contracts
Derivative Instruments, Gain (Loss) [Line Items]
Notional	$ 4,264	$ 4,096
Assets	24	8
Liabilities	122	190
Customer interest rate contracts | Customer Interest Rate Contracts Hedging  | Hedging Instruments And Hedged Items
Derivative Instruments, Gain (Loss) [Line Items]
Notional	8,016	8,301
Assets	39	10
Liabilities	226	372
Offsetting upstream interest rate contracts
Derivative Instruments, Gain (Loss) [Line Items]
Notional	4,442	4,265
Assets	84	134
Liabilities	24	9
Offsetting upstream interest rate contracts | Customer Interest Rate Contracts Hedging  | Hedging Instruments And Hedged Items
Derivative Instruments, Gain (Loss) [Line Items]
Notional	8,316	8,301
Assets	225	369
Liabilities	$ 40	$ 11