Net Interest Revenue (Components Of Interest Revenue And Interest Expenses) (Details) (USD $) In Millions	3 Months Ended				9 Months Ended
	Sep. 30, 2011		Sep. 30, 2010		Sep. 30, 2011		Sep. 30, 2010
Net Interest Revenue
Deposits with banks	$ 39		$ 22		$ 94		$ 63
U.S. Treasury and federal agencies	186		198		590		507
State and political subdivisions	55		56		166		166
Other investments	374		551		1,093		1,619
Securities purchased under resale agreements	6		7		22		17
Loans and leases	68	[1]	69	[1]	215	[1]	254	[1]
Other interest-earning assets			1		1		2
Total interest revenue	728		904		2,181		2,628
Deposits	52		62		154		141
Short-term borrowings	23	[1]	46	[1]	74	[1]	229	[1]
Long-term debt	73		72		220		215
Other interest-bearing liabilities	2				6
Total interest expense	150		180		454		585
Net interest revenue	578		724		1,727		2,043
Interest expense included in short-term borrowings relating to third-party asset-backed securitization trusts							$ 67

[1] Amount for the nine months ended September 30, 2010 included $67 million related to the third-party asset-backed securitization trusts consolidated into our financial statements on January 1, 2010 in connection with our adoption of new GAAP. These trusts were de-consolidated in June 2010.