Fair Value (Level 3 Total Realized And Unrealized Gains And Losses Recorded In Revenue) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Total Revenue [Member]
Realized and Unrealized Gains and Losses [Line Items]
Total Realized and Unrealized Gains (Losses) Recorded in Revenue	$ 24	$ 81	$ 92	$ 233
Change in Unrealized Gains (Losses) Related to Financial Instruments Held	5	0	14	(5)
Trading services
Realized and Unrealized Gains and Losses [Line Items]
Total Realized and Unrealized Gains (Losses) Recorded in Revenue	7	1	60	7
Change in Unrealized Gains (Losses) Related to Financial Instruments Held	5		14	(5)
Total fee revenue
Realized and Unrealized Gains and Losses [Line Items]
Total Realized and Unrealized Gains (Losses) Recorded in Revenue	7	1	60	7
Change in Unrealized Gains (Losses) Related to Financial Instruments Held	5		14	(5)
Net interest revenue
Realized and Unrealized Gains and Losses [Line Items]
Total Realized and Unrealized Gains (Losses) Recorded in Revenue	17	80	32	226
Change in Unrealized Gains (Losses) Related to Financial Instruments Held	$ 0		$ 0	$ 0