Fair Value Measurements (Carrying Amount and Estimated Fair Value of Financial Instruments Not Recorded at Fair Value) (Details) (USD $) In Millions				6 Months Ended		12 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2011	Dec. 31, 2010	Jun. 30, 2010	Jun. 30, 2011 Carrying Amount [Member]		Dec. 31, 2010 Carrying Amount [Member]		Jun. 30, 2011 Estimated Fair Value [Member]		Dec. 31, 2010 Estimated Fair Value [Member]
Cash and due from banks	$ 987	$ 668	$ 816	$ 987		$ 668		$ 987		$ 668
Interest-bearing deposits with banks	2,479	1,415	3,409	2,479		1,415		2,479		1,415
Loans held-for-sale				20		23		20		23
Total loans, net of allowance for loan losses	38,387	39,335	39,635	38,387	[1]	39,335	[1]	38,456	[1]	39,212	[1]
Customers' liability on acceptances outstanding	10	9	24	10		9		10		9
Nonmarketable equity securities				16	[2]	47	[2]	28	[2]	77	[2]
Loan servicing rights				4		5		4		5
Demand deposits (noninterest-bearing)	16,344	15,538	15,769	16,344		15,538		16,344		15,538
Interest-bearing deposits	25,414	24,933	24,011	25,414		24,933		25,423		24,945
Total deposits	41,758	40,471	39,780	41,758		40,471		41,767		40,483
Short-term borrowings	67	130	200	67		130		67		130
Acceptances outstanding	10	9	24	10		9		10		9
Medium- and long-term debt	5,206	6,138	9,041	5,206		6,138		5,129		6,008
Credit-related financial instruments				(93)		(99)		(93)		(99)
Fair value assets measured on nonrecurring basis impaired loans	736	854
Fair value assets measured on nonrecurring basis nonmarketable equity securities	$ 2	$ 9

[1] Included $736 million and $854 million of impaired loans recorded at fair value on a nonrecurring basis at June 30, 2011 and December 31, 2010, respectively.

[2] Included $2 million and $9 million of nonmarketable equity securities recorded at fair value on a nonrecurring basis at June 30, 2011 and December 31, 2010, respectively.