Fair Value (Level 3 Total Realized And Unrealized Gains And Losses Recorded In Revenue) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Realized and Unrealized Gains and Losses [Line Items]
Change in Unrealized Gains (Losses) Related to Financial Instruments Held	$ (461)	$ 605
Trading Services [Member]
Realized and Unrealized Gains and Losses [Line Items]
Total Realized and Unrealized Gains (Losses) Recorded in Revenue	9	(9)
Change in Unrealized Gains (Losses) Related to Financial Instruments Held	4	1
Total Fee Revenue [Member]
Realized and Unrealized Gains and Losses [Line Items]
Total Realized and Unrealized Gains (Losses) Recorded in Revenue	9	(9)
Change in Unrealized Gains (Losses) Related to Financial Instruments Held	4	1
Net Interest Revenue [Member]
Realized and Unrealized Gains and Losses [Line Items]
Total Realized and Unrealized Gains (Losses) Recorded in Revenue	146	144
Change in Unrealized Gains (Losses) Related to Financial Instruments Held	0	0
Total Revenue [Member]
Realized and Unrealized Gains and Losses [Line Items]
Total Realized and Unrealized Gains (Losses) Recorded in Revenue	155	135
Change in Unrealized Gains (Losses) Related to Financial Instruments Held	$ 4	$ 1