Commitments and Guarantees (Net Outstanding Standby Letters of Credit) (Details) (Financial Standby Letter of Credit [Member], USD $) In Billions, unless otherwise specified	Sep. 30, 2012		Dec. 31, 2011
Financial Standby Letter of Credit [Member]
Loss Contingencies [Line Items]
Standby letters of credit	$ 11.4		$ 10.8
Standby letters of credit - Pass	95.00%	[1]	94.00%	[1]
Standby letters of credit - Below pass	5.00%	[2]	6.00%	[2]

[1] Indicates that expected risk of loss is currently low.

[2] Indicates a higher degree of risk of default.