Net Interest Revenue (Components of Interest Revenue and Interest Expenses) (Details) (USD $) In Millions	3 Months Ended				6 Months Ended
	Jun. 30, 2011		Jun. 30, 2010		Jun. 30, 2011		Jun. 30, 2010
Net Interest Revenue
Deposits with banks	$ 28		$ 22		$ 55		$ 41
U.S. Treasury and federal agencies	198		170		404		309
State and political subdivisions	55		56		111		110
Other investments	364		517		719		1,067
Securities purchased under resale agreements	6		6		16		10
Loans and leases	67	[1]	74	[1]	147	[1]	185	[1]
Other interest-earning assets	1		1		1		2
Total interest revenue	719		846		1,453		1,724
Deposits	44		46		102		79
Short-term borrowings	24	[1]	70	[1]	51	[1]	181	[1]
Long-term debt	76		71		147		143
Other interest-bearing liabilities	3		1		4		2
Total interest expense	147		188		304		405
Net interest revenue	572		658		1,149		1,319
Interest expense included in short-term borrowings relating to third-party asset-backed securitization trusts			$ 14				$ 67

[1] Amounts for the three and six months ended June 30, 2010 included $14 million and $67 million, respectively, 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 during the three months ended September 30, 2010.