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Derivatives - Derivatives Associated with Interest Rate Risk Management Activities (Details) - USD ($) $ in Millions | Sep. 30, 2025 | Dec. 31, 2024
--- | --- | ---
Customer interest rate contracts |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |
Notional | $ 4,444 | $ 4,096
Assets | 26 | 8
Liabilities | 108 | 190
Customer interest rate contracts | Customer Interest Rate Contracts Hedging | Hedging Instruments And Hedged Items |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |
Notional | 7,988 | 8,301
Assets | 41 | 10
Liabilities | 202 | 372
Offsetting upstream interest rate contracts |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |
Notional | 4,603 | 4,265
Assets | 73 | 134
Liabilities | 25 | 9
Offsetting upstream interest rate contracts | Customer Interest Rate Contracts Hedging | Hedging Instruments And Hedged Items |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |
Notional | 8,288 | 8,301
Assets | 201 | 369
Liabilities | $ 42 | $ 11

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