Financial Derivatives (Derivatives Designated in GAAP Hedge Relationships - Fair Value Hedges) (Details) (Fair Value Hedging [Member], Designated as Hedging Instrument [Member], Interest Rate Contracts [Member], USD $) In Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Derivatives, Fair Value [Line Items]
Gain (Loss) Recognized in Income on Derivatives	$ 270	$ 215	$ 314	$ 614
Gain (Loss) on Related Hedged Items Recognized in Income	(263)	(225)	(329)	(622)
US Treasury and Government Agencies Securities [Member] | Investment Securities Interest Income [Member]
Derivatives, Fair Value [Line Items]
Gain (Loss) Recognized in Income on Derivatives	(129)	(48)	(154)	(75)
Gain (Loss) on Related Hedged Items Recognized in Income	135	45	161	71
Other Debt Securities [Member] | Investment Securities Interest Income [Member]
Derivatives, Fair Value [Line Items]
Gain (Loss) Recognized in Income on Derivatives	(15)		(24)
Gain (Loss) on Related Hedged Items Recognized in Income	15		24
Federal Home Loans Bank Borrowings [Member] | Borrowed Funds Interest Expense [Member]
Derivatives, Fair Value [Line Items]
Gain (Loss) Recognized in Income on Derivatives		(17)		(65)
Gain (Loss) on Related Hedged Items Recognized in Income		16		63
Subordinated Debts [Member] | Borrowed Funds Interest Expense [Member]
Derivatives, Fair Value [Line Items]
Gain (Loss) Recognized in Income on Derivatives	193	135	223	395
Gain (Loss) on Related Hedged Items Recognized in Income	(193)	(137)	(236)	(409)
Bank Notes And Senior Debt [Member] | Borrowed Funds Interest Expense [Member]
Derivatives, Fair Value [Line Items]
Gain (Loss) Recognized in Income on Derivatives	221	145	269	359
Gain (Loss) on Related Hedged Items Recognized in Income	$ (220)	$ (149)	$ (278)	$ (347)