Net Interest Revenue (Components Of Interest Revenue And Interest Expenses) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
Net Interest Revenue [Abstract]
Deposits with banks	$ 141		$ 149		$ 93
U.S. Treasury and federal agencies	799		775		682
State and political subdivisions	215		221		222
Other investments	1,552		1,493		2,109
Securities purchased under resale agreements	51		28		24
Loans and leases	253	[1]	278	[1]	329	[1]
Other interest-earning assets	3		2		3
Interest revenue	3,014		2,946		3,462
Deposits	166		220		213
Short-term borrowings	73		96		257
Long-term debt	222		289		286
Other interest-bearing liabilities	15		8		7
Total interest expense	476		613		763
Net interest revenue	2,538		2,333		2,699
Interest expense included in short term borrowings relating to third party asset backed securitization trusts					$ 67

[1] Amounts for 2010 included $67 million of interest revenue and interest expense 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.