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				6 Months Ended
	Jun. 30, 2017		Jun. 30, 2016		Jun. 30, 2017		Jun. 30, 2016	Dec. 31, 2016
Derivative [Line Items]
Total derivatives, Notional amount	$ 6,314				$ 6,314			$ 6,209
Amount of derivative gain (loss), recognized in OCI	2		$ 8		0		$ 28
Amount of derivative gain (loss), Reclassified from AOCI to interest income	1		3		3		6
Derivatives instruments, Noninterest income (expense)	7		6		11		8
Derivatives designated as hedging instruments, Offset to interest expense	0		0		0		0
Other Assets [Member]
Derivative [Line Items]
Derivatives hedging instruments, assets	46				46			64
Other Liabilities [Member]
Derivative [Line Items]
Derivatives hedging instruments, liabilities	38				38			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			1,388
Amount of derivative gain (loss), recognized in OCI	2		8		0		28
Amount of derivative gain (loss), Reclassified from AOCI to interest income	1	[1]	3	[1]	3	[1]	6
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	4,926				4,926			4,821
Derivatives Not Designated As Hedging Instruments [Member] | Other Assets [Member]
Derivative [Line Items]
Derivatives hedging instruments, assets	46				46			62
Derivatives Not Designated As Hedging Instruments [Member] | Other Liabilities [Member]
Derivative [Line Items]
Derivatives hedging instruments, liabilities	38				38			58
Derivatives Not Designated As Hedging Instruments [Member] | Foreign Exchange [Member]
Derivative [Line Items]
Total derivatives, Notional amount	318				318			424
Derivatives instruments, Noninterest income (expense)	4		3		7		5
Derivatives Not Designated As Hedging Instruments [Member] | Foreign Exchange [Member] | Other Assets [Member]
Derivative [Line Items]
Derivatives hedging instruments, assets	8				8			11
Derivatives Not Designated As Hedging Instruments [Member] | Foreign Exchange [Member] | Other Liabilities [Member]
Derivative [Line Items]
Derivatives hedging instruments, liabilities	6				6			9
Derivatives Not Designated As Hedging Instruments [Member] | Interest Rate Swaps [Member]
Derivative [Line Items]
Total derivatives, Notional amount	196				196			235
Derivatives instruments, Noninterest income (expense)	0		2		0		2
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	4,412				4,412			4,162
Derivatives instruments, Noninterest income (expense)	3		$ 1		4		$ 1
Derivatives Not Designated As Hedging Instruments [Member] | Interest Rate Swaps For Customers [Member] | Other Assets [Member]
Derivative [Line Items]
Derivatives hedging instruments, assets	37				37			49
Derivatives Not Designated As Hedging Instruments [Member] | Interest Rate Swaps For Customers [Member] | Other Liabilities [Member]
Derivative [Line Items]
Derivatives hedging instruments, liabilities	$ 32				$ 32			$ 49

[1] Amounts recognized in OCI and reclassified from AOCI represent the effective portion of the derivative gain (loss). For the 12 months following June 30, 2017, we estimate that no significant amount will be reclassified from AOCI into interest income.