Derivative Financial Instruments And Hedging Activities (Schedule Of Derivative Instruments Notional And Fair Values) (Details) - USD ($) $ in Millions	Mar. 31, 2023	Dec. 31, 2022
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	$ 157,276	$ 151,907
Estimated Fair Value, Gain	2,346	2,609
Estimated Fair Value, Loss	2,852	3,378
Derivative Asset, Fair Value of Derivative Contracts Offset in Accordance with Entity's Policy that were Offset Under Master Netting Agreements	2,249	2,504
Derivative Liability, Fair Value of Derivative Contracts Offset In Accordance with Policy Election that were Offset Under Master Netting Agreements	1,646	1,925
Derivative Asset	97	105
Derivative Liability	1,206	1,453
Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	30,723	32,023
Estimated Fair Value, Gain	98	20
Estimated Fair Value, Loss	628	826
Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	126,553	119,884
Estimated Fair Value, Gain	2,248	2,589
Estimated Fair Value, Loss	2,224	2,552
Interest Rate Swaps [Member] \| Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	102,385	94,220
Interest Rate Swaps [Member] \| Not Designated as Hedging Instrument [Member] \| Other Assets [Member]
Derivatives, Fair Value [Line Items]
Estimated Fair Value, Gain	1,961	2,315
Interest Rate Swaps [Member] \| Not Designated as Hedging Instrument [Member] \| Other Liabilities [Member]
Derivatives, Fair Value [Line Items]
Estimated Fair Value, Loss	1,960	2,335
Interest Rate Options [Member] \| Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	11,417	12,506
Interest Rate Options [Member] \| Not Designated as Hedging Instrument [Member] \| Other Assets [Member]
Derivatives, Fair Value [Line Items]
Estimated Fair Value, Gain	83	94
Interest Rate Options [Member] \| Not Designated as Hedging Instrument [Member] \| Other Liabilities [Member]
Derivatives, Fair Value [Line Items]
Estimated Fair Value, Loss	68	85
Interest Rate Futures And Forward Commitments [Member] \| Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	912	985
Interest Rate Futures And Forward Commitments [Member] \| Not Designated as Hedging Instrument [Member] \| Other Assets [Member]
Derivatives, Fair Value [Line Items]
Estimated Fair Value, Gain	7	8
Interest Rate Futures And Forward Commitments [Member] \| Not Designated as Hedging Instrument [Member] \| Other Liabilities [Member]
Derivatives, Fair Value [Line Items]
Estimated Fair Value, Loss	6	5
Other Contract [Member] \| Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	11,839	12,173
Other Contract [Member] \| Not Designated as Hedging Instrument [Member] \| Other Assets [Member]
Derivatives, Fair Value [Line Items]
Estimated Fair Value, Gain	197	172
Other Contract [Member] \| Not Designated as Hedging Instrument [Member] \| Other Liabilities [Member]
Derivatives, Fair Value [Line Items]
Estimated Fair Value, Loss	190	127
Fair Value Hedging [Member] \| Interest Rate Swaps [Member] \| Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	1,423	1,423
Fair Value Hedging [Member] \| Interest Rate Swaps [Member] \| Designated as Hedging Instrument [Member] \| Other Assets [Member]
Derivatives, Fair Value [Line Items]
Estimated Fair Value, Gain	0	1
Fair Value Hedging [Member] \| Interest Rate Swaps [Member] \| Designated as Hedging Instrument [Member] \| Other Liabilities [Member]
Derivatives, Fair Value [Line Items]
Estimated Fair Value, Loss	136	158
Cash Flow Hedging [Member] \| Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	29,300	30,600
Estimated Fair Value, Gain	98	19
Estimated Fair Value, Loss	492	668
Cash Flow Hedging [Member] \| Interest Rate Swaps [Member] \| Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	27,800	30,600
Cash Flow Hedging [Member] \| Interest Rate Swaps [Member] \| Designated as Hedging Instrument [Member] \| Other Assets [Member]
Derivatives, Fair Value [Line Items]
Estimated Fair Value, Gain	75	19
Cash Flow Hedging [Member] \| Interest Rate Swaps [Member] \| Designated as Hedging Instrument [Member] \| Other Liabilities [Member]
Derivatives, Fair Value [Line Items]
Estimated Fair Value, Loss	473	668
Cash Flow Hedging [Member] \| Interest Rate Options [Member] \| Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	1,500	0
Cash Flow Hedging [Member] \| Interest Rate Options [Member] \| Designated as Hedging Instrument [Member] \| Other Assets [Member]
Derivatives, Fair Value [Line Items]
Estimated Fair Value, Gain	23	0
Cash Flow Hedging [Member] \| Interest Rate Options [Member] \| Designated as Hedging Instrument [Member] \| Other Liabilities [Member]
Derivatives, Fair Value [Line Items]
Estimated Fair Value, Loss	$ 19	$ 0

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