Fair Value Measurements (Details 2) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended						3 Months Ended		6 Months Ended							3 Months Ended		6 Months Ended			3 Months Ended		6 Months Ended		3 Months Ended		6 Months Ended		3 Months Ended		6 Months Ended		3 Months Ended		6 Months Ended
	Jun. 30, 2012 Interest rate [Member]	Jun. 30, 2011 Interest rate [Member]	Jun. 30, 2012 Interest rate [Member]	Jun. 30, 2011 Interest rate [Member]	Jun. 30, 2011 Energy and commodity [Member]	Jun. 30, 2012 Energy and commodity [Member]	Mar. 31, 2012 Energy and commodity [Member]	Dec. 31, 2011 Energy and commodity [Member]	Jun. 30, 2012 Credit [Member]	Jun. 30, 2011 Credit [Member]	Jun. 30, 2012 Credit [Member]	Jun. 30, 2011 Credit [Member]	Jun. 30, 2012 Trading Account Assets [Member] Other mortgage-backed securities [Member]	Mar. 31, 2012 Trading Account Assets [Member] Other mortgage-backed securities [Member]	Jun. 30, 2011 Trading Account Assets [Member] Other mortgage-backed securities [Member]	Mar. 31, 2011 Trading Account Assets [Member] Other mortgage-backed securities [Member]	Dec. 31, 2010 Trading Account Assets [Member] Other mortgage-backed securities [Member]	Jun. 30, 2012 Trading Account Assets [Member] Other securities [Member]	Jun. 30, 2011 Trading Account Assets [Member] Other securities [Member]	Jun. 30, 2012 Trading Account Assets [Member] Other securities [Member]	Jun. 30, 2011 Trading Account Assets [Member] Other securities [Member]	Jul. 31, 2012 Trading Account Assets [Member] Other securities [Member]	Jun. 30, 2012 Other Investments [Member] Principal Direct Investments [Member]	Jun. 30, 2011 Other Investments [Member] Principal Direct Investments [Member]	Jun. 30, 2012 Other Investments [Member] Principal Direct Investments [Member]	Jun. 30, 2011 Other Investments [Member] Principal Direct Investments [Member]	Jun. 30, 2012 Other Investments [Member] Principal Indirect Investments [Member]	Jun. 30, 2011 Other Investments [Member] Principal Indirect Investments [Member]	Jun. 30, 2012 Other Investments [Member] Principal Indirect Investments [Member]	Jun. 30, 2011 Other Investments [Member] Principal Indirect Investments [Member]	Jun. 30, 2012 Other Investments [Member] Equity and Mezzanine Direct Investments [Member]	Jun. 30, 2011 Other Investments [Member] Equity and Mezzanine Direct Investments [Member]	Jun. 30, 2012 Other Investments [Member] Equity and Mezzanine Direct Investments [Member]	Jun. 30, 2011 Other Investments [Member] Equity and Mezzanine Direct Investments [Member]	Jun. 30, 2012 Other Investments [Member] Equity and Mezzanine Indirect Investments [Member]	Jun. 30, 2011 Other Investments [Member] Equity and Mezzanine Indirect Investments [Member]	Jun. 30, 2012 Other Investments [Member] Equity and Mezzanine Indirect Investments [Member]	Jun. 30, 2011 Other Investments [Member] Equity and Mezzanine Indirect Investments [Member]
Changes in Level 3 Fair Value Measurements
Beginning Balance	$ 36	$ 81	$ 38	$ 75	$ 1	$ (1)	$ (1)	$ (1)	$ 5	$ 4	$ (21)	$ 11	$ 35	$ 1	$ 1	$ 1	$ 1				$ 21	$ 57	$ 226	$ 395	$ 225	$ 372	$ 485	$ 548	$ 473	$ 526	$ 15	$ 25	$ 15	$ 20	$ 42	$ 27	$ 36	$ 30
Gain (losses) included in earnings	2	10	(3)	14	(1)				(2)	(9)	(7)	(10)	2					(5)	3	(2)			7		8	2	20	10	43	43	3	8	3	13	5	1	6
Purchases		11	1	11						6											3		9	2	10	30	10	32	20	46					1	7	4	9
Sales		(18)	(1)	(20)									(32)										(11)	(2)	(12)	(9)	(33)	(11)	(54)	(36)
Settlements									2	7	33	7						5	(3)	2	(24)											(19)		(19)	(2)	(2)	(3)	(3)
Transfers into Level 3		3	4	10														57		57															(3)
Transfers out of Level 3	(3)	(6)	(4)	(9)									(4)											(125)		(125)		(109)		(109)								(3)
Ending Balance	35	81	35	81		(1)	(1)	(1)	5	8	5	8	1	1	1	1	1	57		57		57	231	270	231	270	482	470	482	470	18	14	18	14	43	33	43	33
Unrealized gains (losses) included in earnings																		$ (5)	$ 3	$ (2)	$ 3		$ 7	$ 6	$ 8	$ 8	$ 9	$ 4	$ 28	$ 28	$ 4	$ 22	$ 10	$ 32	$ 2	$ 1	$ 6	$ (3)