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Derivatives - Derivatives Associated With Cash Flow Hedges (Details) - Cash Flow Hedge - Hedging Instruments And Hedged Items - USD ($) $ in Millions | Jun. 30, 2021 | Dec. 31, 2020
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Interest Rate Contract |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |
Variability in cash flows related to debt instruments (primarily loans) | $ 1,100 | $ 1,250
Interest Rate Swap |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |
Notional | 1,100 | 1,250
Assets | 23 | 32
Liabilities | $ 0 | $ 0

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