Fair Value Measurements (Estimated Fair Values Of Financial Instruments Not Recorded At Fair Value In Their Entirety On A Recurring Basis) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013		Dec. 31, 2012
Cash and due from banks	$ 1,140		$ 1,395
Federal funds sold	0		100
Interest-bearing deposits with banks	5,311		3,039
Total loans, net of allowance for loan losses	44,872		45,428
Demand deposits (noninterest-bearing)	23,875		23,279
Customer certificates of deposit	5,063		5,531
Total deposits	53,292		52,191
Short-term borrowings	253		110
Medium- and long-term debt	3,543		4,720
Fair value assets measured on nonrecurring basis impaired loans	128		214
Fair value assets measured on nonrecurring basis nonmarketable equity securities	2		2
Carrying Amount [Member]
Cash and due from banks	1,140		1,395
Federal funds sold			100
Interest-bearing deposits with banks	5,311		3,039
Loans held-for-sale	4		12
Total loans, net of allowance for loan losses	44,872	[1]	45,428	[1]
Customers' liability on acceptances outstanding	11		18
Nonmarketable equity securities	12	[2]	13	[2]
Restricted equity investments	133		174
Demand deposits (noninterest-bearing)	23,875		23,279
Interest-bearing deposits	24,354		23,381
Customer certificates of deposit	5,063		5,531
Total deposits	53,292		52,191
Short-term borrowings	253		110
Acceptances outstanding	11		18
Medium- and long-term debt	3,543		4,720
Credit-related financial instruments	(88)		(103)
Estimated Fair Value [Member]
Cash and due from banks	1,140		1,395
Federal funds sold			100
Interest-bearing deposits with banks	5,311		3,039
Loans held-for-sale	4		12
Total loans, net of allowance for loan losses	44,801	[1]	45,649	[1]
Customers' liability on acceptances outstanding	11		18
Nonmarketable equity securities	19	[2]	22	[2]
Restricted equity investments	133		174
Demand deposits (noninterest-bearing)	23,875		23,279
Interest-bearing deposits	24,354		23,381
Customer certificates of deposit	5,055		5,535
Total deposits	53,284		52,195
Short-term borrowings	253		110
Acceptances outstanding	11		18
Medium- and long-term debt	3,540		4,685
Credit-related financial instruments	(88)		(103)
Level 1
Cash and due from banks	1,140		1,395
Federal funds sold			100
Interest-bearing deposits with banks	5,311		3,039
Loans held-for-sale	0		0
Total loans, net of allowance for loan losses	0	[1]	0	[1]
Customers' liability on acceptances outstanding	11		18
Nonmarketable equity securities	0	[2]	0	[2]
Restricted equity investments	133		174
Demand deposits (noninterest-bearing)	0		0
Interest-bearing deposits	0		0
Customer certificates of deposit	0		0
Total deposits	0		0
Short-term borrowings	253		110
Acceptances outstanding	11		18
Medium- and long-term debt	0		0
Credit-related financial instruments	0		0
Level 2
Cash and due from banks	0		0
Federal funds sold			0
Interest-bearing deposits with banks	0		0
Loans held-for-sale	4		12
Total loans, net of allowance for loan losses	0	[1]	0	[1]
Customers' liability on acceptances outstanding	0		0
Nonmarketable equity securities	0	[2]	0	[2]
Restricted equity investments	0		0
Demand deposits (noninterest-bearing)	23,875		23,279
Interest-bearing deposits	24,354		23,381
Customer certificates of deposit	5,055		5,535
Total deposits	53,284		52,195
Short-term borrowings	0		0
Acceptances outstanding	0		0
Medium- and long-term debt	3,540		4,685
Credit-related financial instruments	0		0
Level 3
Cash and due from banks	0		0
Federal funds sold			0
Interest-bearing deposits with banks	0		0
Loans held-for-sale	0		0
Total loans, net of allowance for loan losses	44,801	[1]	45,649	[1]
Customers' liability on acceptances outstanding	0		0
Nonmarketable equity securities	19	[2]	22	[2]
Restricted equity investments	0		0
Demand deposits (noninterest-bearing)	0		0
Interest-bearing deposits	0		0
Customer certificates of deposit	0		0
Total deposits	0		0
Short-term borrowings	0		0
Acceptances outstanding	0		0
Medium- and long-term debt	0		0
Credit-related financial instruments	$ (88)		$ (103)

[1] Included $128 million and $214 million of impaired loans recorded at fair value on a nonrecurring basis at December 31, 2013 and 2012, respectively.

[2] Included $2 million of nonmarketable equity securities recorded at fair value on a nonrecurring basis at both December 31, 2013 and 2012.