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Derivatives - Derivatives Associated with Cash Flow Hedges and Mortgage Banking Hedges (Details) - Hedging Instruments And Hedged Items - USD ($) $ in Millions | Sep. 30, 2025 | Dec. 31, 2024
--- | --- | ---
Interest Rate Contract | Cash Flow Hedge |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |
Variability in cash flows related to debt instruments (primarily loans) | $ 5,000 | $ 5,000
Interest rate contracts | Cash Flow Hedge |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |
Notional | 5,000 | 5,000
Assets | 0 | 0
Liabilities | 15 | 67
Option contracts written | Mortgage Banking Hedges |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |
Notional | 159 | 51
Assets | 1 | 0
Liabilities | 0 | 0
Forward contracts written | Mortgage Banking Hedges |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |
Notional | 169 | 100
Assets | 0 | 1
Liabilities | $ 0 | $ 0

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