Derivative Financial Instruments And Hedging Activities (Schedule Of The Effect Of Derivative Instruments On The Statements Of Operations) (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Derivative Instruments, Gain (Loss) [Line Items]
Debt securities	$ 1,145	$ 925	$ 749
Long-term borrowings	(299)	(279)	(226)
Deposits	(1,766)	(1,971)	(1,255)
Fair Value Hedging \| Interest Rate Contract \| Taxable Debt Securities in Interest Income [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amounts Related to Interest Settlements on Derivatives	20	8	(1)
Gain or (Loss) Recognized in Income on Derivatives	(57)	27	(6)
Gain or (Loss) Recognized in Income on Related Hedged Item	57	(27)	6
Gain (Loss) on Fair Value Hedges Recognized in Earnings	20	8	(1)
Fair Value Hedging \| Interest Rate Contract \| Long-term Borrowings In Interest Expense [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amounts Related to Interest Settlements on Derivatives	(32)	(67)	(64)
Gain or (Loss) Recognized in Income on Derivatives	39	22	46
Gain or (Loss) Recognized in Income on Related Hedged Item	(39)	(22)	(46)
Gain (Loss) on Fair Value Hedges Recognized in Earnings	$ (32)	(67)	$ (64)
Fair Value Hedging \| Interest Rate Contract \| Deposits
Derivative Instruments, Gain (Loss) [Line Items]
Amounts Related to Interest Settlements on Derivatives		(1)
Gain or (Loss) Recognized in Income on Derivatives		0
Gain or (Loss) Recognized in Income on Related Hedged Item		0
Gain (Loss) on Fair Value Hedges Recognized in Earnings		$ (1)

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