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				9 Months Ended
	Sep. 30, 2017		Sep. 30, 2016		Sep. 30, 2017		Sep. 30, 2016	Dec. 31, 2016
Derivative [Line Items]
Total derivatives, Notional amount	$ 6,221				$ 6,221			$ 6,209
Amount of derivative gain (loss), recognized in OCI	0		$ (5)		0		$ 23
Amount of derivative gain (loss), Reclassified from AOCI to interest income	0		3		3		9
Derivatives instruments, Noninterest income (expense)	8		8		19		16
Derivatives designated as hedging instruments, Offset to interest expense	0		0		0		0
Other Assets [Member]
Derivative [Line Items]
Derivatives hedging instruments, assets	43				43			64
Other Liabilities [Member]
Derivative [Line Items]
Derivatives hedging instruments, liabilities	35				35			59
Derivatives Designated As Hedging Instruments [Member] | Interest Rate Swaps [Member] | Cash Flow Hedging [Member]
Derivative [Line Items]
Total derivatives, Notional amount	1,138				1,138			1,388
Amount of derivative gain (loss), recognized in OCI	0		(5)		0		23
Amount of derivative gain (loss), Reclassified from AOCI to interest income	0	[1]	3	[1]	3	[1]	9
Derivatives Designated As Hedging Instruments [Member] | Interest Rate Swaps [Member] | Other Assets [Member] | Cash Flow Hedging [Member]
Derivative [Line Items]
Derivatives hedging instruments, assets	0				0			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	0				0			1
Derivatives Not Designated As Hedging Instruments [Member]
Derivative [Line Items]
Total derivatives, Notional amount	5,083				5,083			4,821
Derivatives Not Designated As Hedging Instruments [Member] | Other Assets [Member]
Derivative [Line Items]
Derivatives hedging instruments, assets	43				43			62
Derivatives Not Designated As Hedging Instruments [Member] | Other Liabilities [Member]
Derivative [Line Items]
Derivatives hedging instruments, liabilities	35				35			58
Derivatives Not Designated As Hedging Instruments [Member] | Foreign Exchange [Member]
Derivative [Line Items]
Total derivatives, Notional amount	280				280			424
Derivatives instruments, Noninterest income (expense)	4		3		12		8
Derivatives Not Designated As Hedging Instruments [Member] | Foreign Exchange [Member] | Other Assets [Member]
Derivative [Line Items]
Derivatives hedging instruments, assets	6				6			11
Derivatives Not Designated As Hedging Instruments [Member] | Foreign Exchange [Member] | Other Liabilities [Member]
Derivative [Line Items]
Derivatives hedging instruments, liabilities	5				5			9
Derivatives Not Designated As Hedging Instruments [Member] | Interest Rate Swaps [Member]
Derivative [Line Items]
Total derivatives, Notional amount	205				205			235
Derivatives instruments, Noninterest income (expense)	0		1		(1)		3
Derivatives Not Designated As Hedging Instruments [Member] | Interest Rate Swaps [Member] | Other Assets [Member]
Derivative [Line Items]
Derivatives hedging instruments, assets	1				1			2
Derivatives Not Designated As Hedging Instruments [Member] | Interest Rate Swaps [Member] | Other Liabilities [Member]
Derivative [Line Items]
Derivatives hedging instruments, liabilities	0				0			0
Derivatives Not Designated As Hedging Instruments [Member] | Interest Rate Swaps For Customers [Member]
Derivative [Line Items]
Total derivatives, Notional amount	4,598				4,598			4,162
Derivatives instruments, Noninterest income (expense)	4		$ 4		8		$ 5
Derivatives Not Designated As Hedging Instruments [Member] | Interest Rate Swaps For Customers [Member] | Other Assets [Member]
Derivative [Line Items]
Derivatives hedging instruments, assets	36				36			49
Derivatives Not Designated As Hedging Instruments [Member] | Interest Rate Swaps For Customers [Member] | Other Liabilities [Member]
Derivative [Line Items]
Derivatives hedging instruments, liabilities	$ 30				$ 30			$ 49

[1] Amounts recognized in OCI and reclassified from AOCI represent the effective portion of the derivative gain (loss). For the 12 months following September 30, 2017, we estimate that $2 million will be reclassified from AOCI into interest income.