Derivative Financial Instruments And Hedging Activities (Schedule Of Gains (Losses) Recognized Related To Derivatives Not Designated As Hedging Instruments) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Derivative [Line Items]
Gain or (Loss) of Derivatives Not Designated as Hedging Instruments	$ 29	$ 183	$ 117
Mortgage Income [Member] \| Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Gain or (Loss) of Derivatives Not Designated as Hedging Instruments	(64)	111	72
Mortgage Income [Member] \| Interest Rate Swaps [Member] \| Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Gain or (Loss) of Derivatives Not Designated as Hedging Instruments	(45)	83	68
Mortgage Income [Member] \| Interest Rate Options [Member] \| Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Gain or (Loss) of Derivatives Not Designated as Hedging Instruments	(32)	30	(1)
Mortgage Income [Member] \| Interest Rate Futures And Forward Commitments [Member] \| Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Gain or (Loss) of Derivatives Not Designated as Hedging Instruments	13	(2)	5
Capital markets income [Member] \| Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Gain or (Loss) of Derivatives Not Designated as Hedging Instruments	93	72	45
Capital markets income [Member] \| Interest Rate Swaps [Member] \| Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Gain or (Loss) of Derivatives Not Designated as Hedging Instruments	46	21	13
Capital markets income [Member] \| Interest Rate Options [Member] \| Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Gain or (Loss) of Derivatives Not Designated as Hedging Instruments	28	36	23
Capital markets income [Member] \| Interest Rate Futures And Forward Commitments [Member] \| Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Gain or (Loss) of Derivatives Not Designated as Hedging Instruments	15	14	10
Capital markets income [Member] \| Other Contracts [Member] \| Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Gain or (Loss) of Derivatives Not Designated as Hedging Instruments	$ 4	$ 1	$ (1)