Acquisition And Restructuring Costs (Narrative) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended				12 Months Ended		3 Months Ended	9 Months Ended	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Mar. 31, 2012 Business Operations And Information Technology Transformation Program [Member] employees	Mar. 31, 2011 Business Operations And Information Technology Transformation Program [Member]	Dec. 31, 2011 Business Operations And Information Technology Transformation Program [Member] employees	Dec. 31, 2010 Business Operations And Information Technology Transformation Program [Member] employees	Mar. 31, 2012 Expenses Control Measures [Member] employees	Sep. 30, 2011 Expenses Control Measures [Member] employees	Mar. 31, 2012 Intesa, Mourant International Finance Administration And BIAM [Member]	Mar. 31, 2011 Intesa, Mourant International Finance Administration And BIAM [Member]	Mar. 31, 2012 Withdrawal From Fixed Income Trading Initiative [Member]	Mar. 31, 2012 Pre-Tax Restructuring Charges [Member] Business Operations And Information Technology Transformation Program [Member]	Mar. 31, 2012 Pre-Tax Restructuring Charges [Member] Expenses Control Measures [Member]	Dec. 31, 2011 Pre-Tax Restructuring Charges [Member] Expenses Control Measures [Member]	Mar. 31, 2012 Employee Severance [Member] Business Operations And Information Technology Transformation Program [Member] employees	Mar. 31, 2012 Involuntarily Terminated [Member] employees	Mar. 31, 2012 Involuntarily Terminated [Member] Business Operations And Information Technology Transformation Program [Member] employees
Business Acquisition [Line Items]
Acquisition and restructuring costs	$ 21	$ 19
Acquisition Related Costs									13	14
Additional restructuring-related accruals	15		15		133	156						304	7	120
Number of employees involuntarily terminated			49		530	1,400	215	442							1,930	230	1,381
Percentage of global workforce						5.00%
Restructuring Charges	$ 8	$ 5	$ 15	$ 5							$ 7