Acquisition and Restructuring Costs (Narrative) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended										3 Months Ended	12 Months Ended				26 Months Ended	1 Months Ended	12 Months Ended		13 Months Ended	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2012 Business Operations And Information Technology Transformation Program [Member]	Dec. 31, 2011 Business Operations And Information Technology Transformation Program [Member]	Dec. 31, 2010 Business Operations And Information Technology Transformation Program [Member]	Dec. 31, 2012 Expenses Control Measures [Member]	Dec. 31, 2012 Intesa Sanpaolo S Securities Services [Member]	Dec. 31, 2011 Intesa Sanpaolo S Securities Services [Member]	Dec. 31, 2012 Pre-Tax Restructuring Charges [Member] Business Operations And Information Technology Transformation Program [Member]	Dec. 31, 2011 Pre-Tax Restructuring Charges [Member] Expenses Control Measures [Member]	Dec. 31, 2012 Pre-Tax Restructuring Charges [Member] Expenses Control Measures [Member]	Dec. 31, 2012 Involuntarily Terminated [Member] Business Operations And Information Technology Transformation Program [Member] employees	Dec. 31, 2011 Involuntarily Terminated [Member] Business Operations And Information Technology Transformation Program [Member] employees	Dec. 31, 2010 Involuntarily Terminated [Member] Business Operations And Information Technology Transformation Program [Member] employees	Dec. 31, 2012 Involuntarily Terminated [Member] Business Operations And Information Technology Transformation Program [Member] employees	Dec. 31, 2012 Involuntarily Terminated [Member] Expenses Control Measures [Member] employees	Dec. 31, 2012 Involuntarily Terminated [Member] Expenses Control Measures [Member] employees	Dec. 31, 2011 Involuntarily Terminated [Member] Expenses Control Measures [Member] employees	Dec. 31, 2012 Involuntarily Terminated [Member] Expenses Control Measures [Member] employees	Dec. 31, 2012 2012 GSAS and 2010 Intesa Acquisitions [Member]	Dec. 31, 2011 Intesa and 2010 Mourant International Finance Administration and 2011 Bank of Ireland Asset Management [Member]
Business Acquisition [Line Items]
Income tax expense associated with an indemnification benefit from income tax claim related to acquisition	$ 40	$ 55						$ 40	$ 55
Business Combination, Acquisition Related Costs																					66	71
Restructuring charges, net	199	253	156				132
Restructuring charges, gross							133
Restructuring charges, djustment												(1)
Additional restructuring-related accruals	$ 67			$ 67	$ 133	$ 156				$ 356	$ 120							$ 133
Expected number of employees to be involuntary terminated													164	530	1,400	2,094	630	363	442
Percentage of global workforce															5.00%
Number of employees involuntarily terminated													697	782	550	2,029	40			378