Fair Value Measurements (Details 2) (USD $) In Millions	3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended	9 Months Ended			3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended
	Sep. 30, 2011 Interest rate [Member] Level 3 [Member]	Sep. 30, 2010 Interest rate [Member] Level 3 [Member]	Sep. 30, 2011 Interest rate [Member] Level 3 [Member]	Sep. 30, 2010 Interest rate [Member] Level 3 [Member]	Sep. 30, 2011 Energy and commodity [Member] Level 3 [Member]	Sep. 30, 2010 Energy and commodity [Member] Level 3 [Member]	Sep. 30, 2011 Energy and commodity [Member] Level 3 [Member]	Sep. 30, 2010 Energy and commodity [Member] Level 3 [Member]	Sep. 30, 2011 Credit [Member] Level 3 [Member]	Sep. 30, 2010 Credit [Member] Level 3 [Member]	Sep. 30, 2011 Credit [Member] Level 3 [Member]	Sep. 30, 2010 Credit [Member] Level 3 [Member]	Sep. 30, 2011 Mortgage Backed Securities, Other [Member] Level 3 [Member]	Sep. 30, 2010 Mortgage Backed Securities, Other [Member] Level 3 [Member]	Sep. 30, 2011 Mortgage Backed Securities, Other [Member] Level 3 [Member]	Sep. 30, 2010 Mortgage Backed Securities, Other [Member] Level 3 [Member]	Sep. 30, 2011 Other Debt Securities [Member] Level 3 [Member]	Sep. 30, 2011 Other Debt Securities [Member] Level 3 [Member]	Sep. 30, 2010 Other Debt Securities [Member] Level 3 [Member]	Jun. 30, 2010 Other Debt Securities [Member] Level 3 [Member]	Sep. 30, 2011 Commercial Loan [Member] Level 3 [Member]	Sep. 30, 2010 Commercial Loan [Member] Level 3 [Member]	Sep. 30, 2011 Commercial Loan [Member] Level 3 [Member]	Sep. 30, 2010 Commercial Loan [Member] Level 3 [Member]	Sep. 30, 2011 Principal Direct Investments [Member] Level 3 [Member]	Sep. 30, 2010 Principal Direct Investments [Member] Level 3 [Member]	Sep. 30, 2011 Principal Direct Investments [Member] Level 3 [Member]	Sep. 30, 2010 Principal Direct Investments [Member] Level 3 [Member]	Sep. 30, 2011 Principal Indirect Investments [Member] Level 3 [Member]	Sep. 30, 2010 Principal Indirect Investments [Member] Level 3 [Member]	Sep. 30, 2011 Principal Indirect Investments [Member] Level 3 [Member]	Sep. 30, 2010 Principal Indirect Investments [Member] Level 3 [Member]	Sep. 30, 2011 Equity and Mezzanine Direct Investments [Member] Level 3 [Member]	Sep. 30, 2010 Equity and Mezzanine Direct Investments [Member] Level 3 [Member]	Sep. 30, 2011 Equity and Mezzanine Direct Investments [Member] Level 3 [Member]	Sep. 30, 2010 Equity and Mezzanine Direct Investments [Member] Level 3 [Member]	Sep. 30, 2011 Equity and Mezzanine Indirect Investments [Member] Level 3 [Member]	Sep. 30, 2010 Equity and Mezzanine Indirect Investments [Member] Level 3 [Member]	Sep. 30, 2011 Equity and Mezzanine Indirect Investments [Member] Level 3 [Member]	Sep. 30, 2010 Equity and Mezzanine Indirect Investments [Member] Level 3 [Member]	Sep. 30, 2011 Level 3 [Member] Accrued Income and Other Assets [Member]	Sep. 30, 2010 Level 3 [Member] Accrued Income and Other Assets [Member]	Sep. 30, 2011 Level 3 [Member] Accrued Income and Other Assets [Member]	Dec. 31, 2009 Level 3 [Member] Accrued Income and Other Assets [Member]	Sep. 30, 2011 Commercial Loan [Member]	Dec. 31, 2010 Commercial Loan [Member]
Changes in Level 3 Fair Value Measurements
Balance at January 1, 2011	$ 81	$ 87	$ 75	$ 99	$ 0	$ 0	$ 1	$ 0	$ 8	$ 10	$ 11	$ 9	$ 1	$ 4	$ 1	$ 29	$ 0	$ 21	$ 423	$ 24	$ 0	$ 9		$ 19	$ 270	$ 419	$ 372	$ 538	$ 470	$ 530	$ 526	$ 497	$ 14	$ 24	$ 20	$ 26	$ 33	$ 31	$ 30	$ 31	$ 0	$ 3	$ 0	$ 0	$ 0	$ 0
Gain (losses) included in earnings	40	18	54	18			(1)		(1)	(20)	(11)	(19)				3	(1)	2				(1)		(2)	2	2	4	20	33	15	76	51	4	3	17	8		(1)		(5)
Purchases			11																						8		38		10		56						3		12
Sales	(4)		(24)						(1)		(1)														(15)		(24)		(19)		(55)
Issuances
Settlements									1		8						1	(23)															(5)		(24)				(3)
Purchases, sales, issuances and settlements		(4)		(8)						8		8		(1)		(30)			(399)			2		(7)		(9)		(138)		(16)		(19)		(6)		(19)				4		(3)
Transfers into Level 3	1		11										33		33
Transfers out of Level 3	(4)		13																								125				109								3
Net transfers into (out of) Level 3		(3)		(11)		3		3						(1)								(10)		(10)				(8)								6
Balance at Sep 30, 2011	114	98	114	98	0	3	0	3	7	(2)	7	(2)	34	2	34	2	0	0	24	24	0		0		265	412	265	412	494	529	494	529	13	21	13	21	36	30	36	30	0	0	0	0	0	0
Unrealized gains (losses) included in earnings														$ 1		$ 3	$ (1)	$ 2							$ (3)	$ 1	$ 5	$ 3	$ 27	$ 8	$ 55	$ 40	$ 4	$ 23	$ 36	$ 64		$ (1)	$ (3)	$ (5)