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	Jun. 30, 2012		Dec. 31, 2011		Jun. 30, 2011
Cash and due from banks	$ 1,076		$ 982		$ 987
Interest-bearing deposits with banks	3,065		2,574		2,479
Total loans, net of allowance for loan losses	43,325		41,953		38,387
Demand deposits (noninterest-bearing)	21,330		19,764		16,344
Customer certificates of deposit	6,045		5,808		5,551
Total deposits	49,388		47,755		41,758
Short-term borrowings	83		70		67
Medium- and long-term debt	4,742		4,944		5,206
Fair value assets measured on nonrecurring basis impaired loans	425		564
Fair value assets measured on nonrecurring basis nonmarketable equity securities	1		1
Carrying Amount [Member]
Cash and due from banks	1,076		982
Interest-bearing deposits with banks	3,065		2,574
Loans held-for-sale	32		34
Total loans, net of allowance for loan losses	43,325	[1]	41,953	[1]
Customers' liability on acceptances outstanding	18		22
Nonmarketable equity securities	14	[2]	16	[2]
Demand deposits (noninterest-bearing)	21,330		19,764
Interest-bearing deposits	22,013		22,183
Customer certificates of deposit	6,045		5,808
Total deposits	49,388		47,755
Short-term borrowings	83		70
Acceptances outstanding	18		22
Medium- and long-term debt	4,742		4,944
Credit-related financial instruments	(113)		(101)
Estimated Fair Value [Member]
Cash and due from banks	1,076		982
Interest-bearing deposits with banks	3,065		2,574
Loans held-for-sale	32		34
Total loans, net of allowance for loan losses	43,592	[1]	42,233	[1]
Customers' liability on acceptances outstanding	18		22
Nonmarketable equity securities	27	[2]	27	[2]
Demand deposits (noninterest-bearing)	21,330		19,764
Interest-bearing deposits	22,013		22,183
Customer certificates of deposit	6,046		5,809
Total deposits	49,389		47,756
Short-term borrowings	83		70
Acceptances outstanding	18		22
Medium- and long-term debt	4,655		4,794
Credit-related financial instruments	(113)		(101)
Fair Value, Inputs, Level 1 [Member]
Cash and due from banks	1,076		982
Interest-bearing deposits with banks	3,065		2,574
Loans held-for-sale	0		0
Total loans, net of allowance for loan losses	0	[1]	0	[1]
Customers' liability on acceptances outstanding	18		22
Nonmarketable equity securities	0	[2]	0	[2]
Demand deposits (noninterest-bearing)	0		0
Interest-bearing deposits	0		0
Customer certificates of deposit	0		0
Total deposits	0		0
Short-term borrowings	83		70
Acceptances outstanding	18		22
Medium- and long-term debt	0		0
Credit-related financial instruments	0		0
Fair Value, Inputs, Level 2 [Member]
Cash and due from banks	0		0
Interest-bearing deposits with banks	0		0
Loans held-for-sale	32		34
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]
Demand deposits (noninterest-bearing)	21,330		19,764
Interest-bearing deposits	22,013		22,183
Customer certificates of deposit	6,046		5,809
Total deposits	49,389		47,756
Short-term borrowings	0		0
Acceptances outstanding	0		0
Medium- and long-term debt	4,655		4,794
Credit-related financial instruments	0		0
Fair Value, Inputs, Level 3 [Member]
Cash and due from banks	0		0
Interest-bearing deposits with banks	0		0
Loans held-for-sale	0		0
Total loans, net of allowance for loan losses	43,592	[1]	42,233	[1]
Customers' liability on acceptances outstanding	0		0
Nonmarketable equity securities	27	[2]	27	[2]
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	$ (113)		$ (101)

[1] Included $425 million and $564 million of impaired loans recorded at fair value on a nonrecurring basis at June 30, 2012 and December 31, 2011, respectively.

[2] Included $1 million of nonmarketable equity securities recorded at fair value on a nonrecurring basis at both June 30, 2012 and December 31, 2011.