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, 2020	Dec. 31, 2019	Dec. 31, 2018
Derivative Instruments, Gain (Loss) [Line Items]
Debt securities	$ 582	$ 643	$ 625
Loans, including fees	3,610	3,866	3,613
Long-term borrowings	178	351	322
Fair Value Hedging [Member] \| Loans Including Fees in Interest Income [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amounts Related to Interest Settlements on Derivatives	0	0	0
Gain or (Loss) Recognized in Income on Derivatives	0	0	0
Gain or (Loss) Recognized in Income on Related Hedged Item	0	0	0
Gain (Loss) on Fair Value Hedges Recognized in Earnings	0	0	0
Fair Value Hedging [Member] \| Interest Rate Contract [Member] \| Taxable Debt Securities in Interest Income [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amounts Related to Interest Settlements on Derivatives	0	0	(1)
Gain or (Loss) Recognized in Income on Derivatives	0	(2)	4
Gain or (Loss) Recognized in Income on Related Hedged Item	0	2	(4)
Gain (Loss) on Fair Value Hedges Recognized in Earnings	0	0	(1)
Fair Value Hedging [Member] \| Interest Rate Contract [Member] \| Long-term Borrowings In Interest Expense [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amounts Related to Interest Settlements on Derivatives	(37)	(14)	(15)
Gain or (Loss) Recognized in Income on Derivatives	52	92	1
Gain or (Loss) Recognized in Income on Related Hedged Item	(51)	(92)	(1)
Gain (Loss) on Fair Value Hedges Recognized in Earnings	38	(14)	(15)
Cash Flow Hedging [Member] \| Interest Rate Contract [Member] \| Taxable Debt Securities in Interest Income [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain or (Loss) Reclassified from AOCI into Income	0	0	0
Net Income (Expense) Recognized on Cash Flow Hedges	0	0	0
Cash Flow Hedging [Member] \| Interest Rate Contract [Member] \| Loans Including Fees in Interest Income [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Net Income (Expense) Recognized on Cash Flow Hedges	260	(24)	12
Cash Flow Hedging [Member] \| Interest Rate Contract [Member] \| Long-term Borrowings In Interest Expense [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain or (Loss) Reclassified from AOCI into Income	0	0	0
Net Income (Expense) Recognized on Cash Flow Hedges	$ 0	$ 0	$ 0

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Net Income (Expense) Recognized on Cash Flow Hedges

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Amount of the increase (decrease) in fair value of the hedged item in a fair value hedge recognized in the income statement.

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Amount of increase (decrease) in the fair value of derivatives recognized in the income statement.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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The effective portion of net gain (loss) reclassified from accumulated other comprehensive income into income on derivative instruments designated and qualifying as hedging instruments.

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

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The aggregate interest and fee income generated by: (1) loans the Entity has positive intent and ability to hold for the foreseeable future, or until maturity or payoff, including commercial and consumer loans, whether domestic or foreign, which may consist of: (a) industrial and agricultural; (b) real estate; and (c) real estate construction loans; (d) trade financing; (e) lease financing; (f) home equity lines-of-credit; (g) automobile and other vehicle loans; and (h) credit card and other revolving-type loans and (2) loans and leases held-for-sale which may include mortgage loans, direct financing, and sales-type leases.

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Aggregate amount of interest paid or due on all long-term debt.

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Amount of operating interest income, including amortization and accretion of premiums and discounts, on securities subject to state, federal and other income tax.

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