Derivative Instruments And Hedging Activities (Schedule Of Notional Amounts And Recorded Gross Fair Values And Related Gain (Loss) Of Derivative Instruments) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017		Mar. 31, 2016	Dec. 31, 2016
Derivative [Line Items]
Total derivatives, Notional amount	$ 6,133			$ 6,209
Amount of derivative gain (loss), recognized in OCI	(2)		$ 21
Amount of derivative gain (loss), Reclassified from AOCI to interest income	2		3
Derivatives instruments, Noninterest income (expense)	4		2
Derivatives designated as hedging instruments, Offset to interest expense	0		0
Other Assets [Member]
Derivative [Line Items]
Derivatives hedging instruments, assets	55			64
Other Liabilities [Member]
Derivative [Line Items]
Derivatives hedging instruments, liabilities	56			59
Derivatives Designated As Hedging Instruments [Member] | Interest Rate Swaps [Member] | Cash Flow Hedging [Member]
Derivative [Line Items]
Total derivatives, Notional amount	1,388			1,388
Amount of derivative gain (loss), recognized in OCI	(2)		21
Amount of derivative gain (loss), Reclassified from AOCI to interest income	2	[1]	3
Derivatives Designated As Hedging Instruments [Member] | Interest Rate Swaps [Member] | Other Assets [Member] | Cash Flow Hedging [Member]
Derivative [Line Items]
Derivatives hedging instruments, assets	1			2
Derivatives Designated As Hedging Instruments [Member] | Interest Rate Swaps [Member] | Other Liabilities [Member] | Cash Flow Hedging [Member]
Derivative [Line Items]
Derivatives hedging instruments, liabilities	3			1
Derivatives Not Designated As Hedging Instruments [Member]
Derivative [Line Items]
Total derivatives, Notional amount	4,745			4,821
Derivatives Not Designated As Hedging Instruments [Member] | Other Assets [Member]
Derivative [Line Items]
Derivatives hedging instruments, assets	54			62
Derivatives Not Designated As Hedging Instruments [Member] | Other Liabilities [Member]
Derivative [Line Items]
Derivatives hedging instruments, liabilities	53			58
Derivatives Not Designated As Hedging Instruments [Member] | Foreign Exchange [Member]
Derivative [Line Items]
Total derivatives, Notional amount	438			424
Derivatives instruments, Noninterest income (expense)	4		2
Derivatives Not Designated As Hedging Instruments [Member] | Foreign Exchange [Member] | Other Assets [Member]
Derivative [Line Items]
Derivatives hedging instruments, assets	9			11
Derivatives Not Designated As Hedging Instruments [Member] | Foreign Exchange [Member] | Other Liabilities [Member]
Derivative [Line Items]
Derivatives hedging instruments, liabilities	7			9
Derivatives Not Designated As Hedging Instruments [Member] | Interest Rate Swaps [Member]
Derivative [Line Items]
Total derivatives, Notional amount	201			235
Derivatives instruments, Noninterest income (expense)	(1)		0
Derivatives Not Designated As Hedging Instruments [Member] | Interest Rate Swaps [Member] | Other Assets [Member]
Derivative [Line Items]
Derivatives hedging instruments, assets	1			2
Derivatives Not Designated As Hedging Instruments [Member] | Interest Rate Swaps [Member] | Other Liabilities [Member]
Derivative [Line Items]
Derivatives hedging instruments, liabilities	1			0
Derivatives Not Designated As Hedging Instruments [Member] | Interest Rate Swaps For Customers [Member]
Derivative [Line Items]
Total derivatives, Notional amount	4,106			4,162
Derivatives instruments, Noninterest income (expense)	1		$ 0
Derivatives Not Designated As Hedging Instruments [Member] | Interest Rate Swaps For Customers [Member] | Other Assets [Member]
Derivative [Line Items]
Derivatives hedging instruments, assets	44			49
Derivatives Not Designated As Hedging Instruments [Member] | Interest Rate Swaps For Customers [Member] | Other Liabilities [Member]
Derivative [Line Items]
Derivatives hedging instruments, liabilities	$ 45			$ 49

[1] Amounts recognized in OCI and reclassified from AOCI represent the effective portion of the derivative gain (loss).