Derivative Financial Instruments (Notional Amount of Interest Rate Swap Agreements Designated as Fair Value and Cash Flow Hedges) (Details) (USD $) In Millions	6 Months Ended		12 Months Ended
	Jun. 30, 2011		Dec. 31, 2010
Notional Amount of Fair Value Hedges	$ 4,520		$ 1,761
Notional Amount of Cash Flow Hedges	128		125
Notional Amount of Derivatives	4,648		1,886
Increase in carrying value of long-term debt	90		81
Total Investment Securities Available for Sale [Member]
Notional Amount of Fair Value Hedges	3,820		1,561
Notional Amount of Cash Flow Hedges	128		125
Notional Amount of Derivatives	3,948		1,686
Long-Term Debt [Member]
Notional Amount of Fair Value Hedges	700	[1]	200	[1]
Notional Amount of Derivatives	$ 700	[1]	$ 200	[1]

[1] As of June 30, 2011 and December 31, 2010, fair value hedges of long-term debt increased the carrying value of long-term debt presented in our consolidated statement of condition by $90 million and $81 million, respectively.