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Derivatives - Derivatives Associated With Cash Flow Hedges and Mortgage Banking Hedges (Details) - Hedging Instruments And Hedged Items - USD ($) $ in Millions | Mar. 31, 2024 | Dec. 31, 2023
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Cash Flow Hedge | Interest Rate Contract |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |
Variability in cash flows related to debt instruments (primarily loans) | $ 5,000 | $ 5,200
Cash Flow Hedge | Interest Rate Swap |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |
Notional | 5,000 | 5,200
Assets | 0 | 0
Liabilities | 76 | 32
Mortgage Banking Hedges | Option contracts written |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |
Notional | 102 | 55
Assets | 2 | 1
Liabilities | 0 | 0
Mortgage Banking Hedges | Forward contracts written |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |
Notional | 158 | 93
Assets | 0 | 0
Liabilities | $ 1 | $ 1

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