Credit Quality And Allowance For Credit Losses (Changes In The Allowance For Loan Losses And Related Loan Amounts) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013		Mar. 31, 2012		Dec. 31, 2012
Financing Receivable, Allowance for Credit Losses [Line Items]
Provision for loan losses	$ 16		$ 22
Total allowance for loan losses	617				629
PCI loans	29				36
Total loans	45,067				46,057
Allowance for PCI loans	0				0
Business loans
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans	41,343				42,377
Retail loans
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans	3,724				3,680
Financing Receivable [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at beginning of period	629		726
Loan charge-offs	(38)		(62)
Recoveries on loans previously charged-off	14		17
Net loan charge-offs	(24)		(45)
Provision for loan losses	12		23
Balance at end of period	617		704
As a percentage of total loans	1.37%		1.64%
Allowance for loan losses individually evaluated for impairment	60		144
Allowance for loan losses collectively evaluated for impairment	557		560
Loans individually evaluated for impairment	397		752
Loans collectively evaluated for impairment	44,641		42,188
PCI loans	29	[1]	72	[1]
Total loans	45,067		43,012
Financing Receivable [Member] | Business loans
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at beginning of period	552		648
Loan charge-offs	(34)		(55)
Recoveries on loans previously charged-off	12		14
Net loan charge-offs	(22)		(41)
Provision for loan losses	14		25
Balance at end of period	544		632
As a percentage of total loans	1.32%		1.61%
Allowance for loan losses individually evaluated for impairment	60		143
Allowance for loan losses collectively evaluated for impairment	484		489
Loans individually evaluated for impairment	355		702
Loans collectively evaluated for impairment	40,964		38,523
PCI loans	24	[1]	64	[1]
Total loans	41,343		39,289
Financing Receivable [Member] | Retail loans
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at beginning of period	77		78
Loan charge-offs	(4)		(7)
Recoveries on loans previously charged-off	2		3
Net loan charge-offs	(2)		(4)
Provision for loan losses	(2)		(2)
Balance at end of period	73		72
As a percentage of total loans	1.97%		1.94%
Allowance for loan losses individually evaluated for impairment	0		1
Allowance for loan losses collectively evaluated for impairment	73		71
Loans individually evaluated for impairment	42		50
Loans collectively evaluated for impairment	3,677		3,665
PCI loans	5	[1]	8	[1]
Total loans	$ 3,724		$ 3,723

[1] No allowance for loan losses was required for PCI loans at March 31, 2013 and 2012.