Derivative Financial Instruments And Hedging Activities (Schedule Of The Effect Of Derivative Instruments On The Statements Of Operations) (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2026	Mar. 31, 2025
Derivative Instruments, Gain (Loss) [Line Items]
Debt securities	$ 298	$ 266
Long-term borrowings	(52)	(85)
Income Statement Location [Axis]: us-gaap:InterestExpenseLongTermDebt \| Fair Value Hedging \| Interest Rate Contract
Derivative Instruments, Gain (Loss) [Line Items]
Amounts Related to Interest Settlements on Derivatives	(5)	(14)
Gain or (Loss) Recognized in Income on Derivatives	2	25
Gain or (Loss) Recognized in Income on Related Hedged Item	(2)	(25)
Gain (Loss) on Fair Value Hedges Recognized in Earnings	(5)	(14)
Income Statement Location [Axis]: us-gaap:InterestIncomeSecuritiesTaxable \| Fair Value Hedging \| Interest Rate Contract
Derivative Instruments, Gain (Loss) [Line Items]
Amounts Related to Interest Settlements on Derivatives	1	3
Gain or (Loss) Recognized in Income on Derivatives	29	(46)
Gain or (Loss) Recognized in Income on Related Hedged Item	(29)	46
Gain (Loss) on Fair Value Hedges Recognized in Earnings	$ 1	$ 3

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Total amount of gain (loss) derived from fair value hedges recognized in earnings in the period.

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