Derivative Financial Instruments (Notional Amount Of Interest Rate Swap Agreements Designated As Fair Value And Cash Flow Hedges) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011		Dec. 31, 2010
Derivative [Line Items]
Notional Amount of Fair Value Hedges	$ 3,748		$ 1,761
Notional Amount of Cash Flow Hedges	124		125
Notional Amount of Derivatives	3,872		1,886
Increase in carrying value of long-term debt	140		81
Investment Securities Available For Sale [Member]
Derivative [Line Items]
Notional Amount of Fair Value Hedges	1,298		1,561
Notional Amount of Cash Flow Hedges	124		125
Notional Amount of Derivatives	1,422		1,686
Long-Term Debt [Member]
Derivative [Line Items]
Notional Amount of Fair Value Hedges	2,450	[1]	200	[1]
Notional Amount of Derivatives	$ 2,450	[1]	$ 200	[1]

[1] As of December 31, 2011 and 2010, fair value hedges of long-term debt increased the carrying value of long-term debt presented in our consolidated statement of condition by $140 million and $81 million, respectively.