Fair Value Measurements (Details 2) (USD $) In Millions	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	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		3 Months Ended	6 Months Ended			6 Months Ended
	Jun. 30, 2010	Jun. 30, 2011 Interest rate [Member] Level 3 [Member]	Jun. 30, 2010 Interest rate [Member] Level 3 [Member]	Jun. 30, 2011 Interest rate [Member] Level 3 [Member]	Jun. 30, 2010 Interest rate [Member] Level 3 [Member]	Jun. 30, 2011 Energy and commodity [Member] Level 3 [Member]	Jun. 30, 2011 Energy and commodity [Member] Level 3 [Member]	Jun. 30, 2010 Energy and commodity [Member] Level 3 [Member]	Mar. 31, 2010 Energy and commodity [Member] Level 3 [Member]	Dec. 31, 2009 Energy and commodity [Member] Level 3 [Member]	Jun. 30, 2011 Credit [Member] Level 3 [Member]	Jun. 30, 2011 Credit [Member] Level 3 [Member]	Jun. 30, 2010 Credit [Member] Level 3 [Member]	Mar. 31, 2010 Credit [Member] Level 3 [Member]	Jun. 30, 2011 Mortgage Backed Securities, Other [Member] Level 3 [Member]	Jun. 30, 2010 Mortgage Backed Securities, Other [Member] Level 3 [Member]	Jun. 30, 2011 Mortgage Backed Securities, Other [Member] Level 3 [Member]	Jun. 30, 2010 Mortgage Backed Securities, Other [Member] Level 3 [Member]	Jun. 30, 2011 Other Debt Securities [Member] Level 3 [Member]	Jun. 30, 2010 Other Debt Securities [Member] Level 3 [Member]	Jun. 30, 2011 Other Debt Securities [Member] Level 3 [Member]	Jun. 30, 2010 Other Debt Securities [Member] Level 3 [Member]	Jun. 30, 2011 Commercial Loan [Member] Level 3 [Member]	Jun. 30, 2010 Commercial Loan [Member] Level 3 [Member]	Jun. 30, 2010 Commercial Loan [Member] Level 3 [Member]	Jun. 30, 2011 Principal Direct Investments [Member] Level 3 [Member]	Jun. 30, 2010 Principal Direct Investments [Member] Level 3 [Member]	Jun. 30, 2011 Principal Direct Investments [Member] Level 3 [Member]	Jun. 30, 2010 Principal Direct Investments [Member] Level 3 [Member]	Jun. 30, 2011 Principal Indirect Investments [Member] Level 3 [Member]	Jun. 30, 2010 Principal Indirect Investments [Member] Level 3 [Member]	Jun. 30, 2011 Principal Indirect Investments [Member] Level 3 [Member]	Jun. 30, 2010 Principal Indirect Investments [Member] Level 3 [Member]	Jun. 30, 2011 Equity and Mezzanine Direct Investments [Member] Level 3 [Member]	Jun. 30, 2010 Equity and Mezzanine Direct Investments [Member] Level 3 [Member]	Jun. 30, 2011 Equity and Mezzanine Direct Investments [Member] Level 3 [Member]	Jun. 30, 2010 Equity and Mezzanine Direct Investments [Member] Level 3 [Member]	Jun. 30, 2011 Equity and Mezzanine Indirect Investments [Member] Level 3 [Member]	Jun. 30, 2010 Equity and Mezzanine Indirect Investments [Member] Level 3 [Member]	Jun. 30, 2011 Equity and Mezzanine Indirect Investments [Member] Level 3 [Member]	Jun. 30, 2010 Equity and Mezzanine Indirect Investments [Member] Level 3 [Member]	Jun. 30, 2011 Level 3 [Member]	Dec. 31, 2009 Level 3 [Member]	Jun. 30, 2011 Level 3 [Member] Accrued Income and Other Assets [Member]	Jun. 30, 2011 Level 3 [Member] Accrued Income and Other Assets [Member]	Jun. 30, 2010 Level 3 [Member] Accrued Income and Other Assets [Member]	Mar. 31, 2010 Level 3 [Member] Accrued Income and Other Assets [Member]	Jun. 30, 2011 Commercial Loan [Member]
Changes in Level 3 Fair Value Measurements
Balance at January 1, 2011		$ 81	$ 80	$ 75	$ 99	$ 0	$ 1	$ 0	$ 0	$ 0	$ 4	$ 11		$ 10	$ 1	$ 29	$ 1	$ 29	$ 0	$ 199	$ 21	$ 423	$ 0	$ 11	$ 19	$ 395	$ 534	$ 372	$ 538	$ 548	$ 518	$ 526	$ 497	$ 25	$ 32	$ 20	$ 26	$ 27	$ 33	$ 30	$ 31		$ 9	$ 0	$ 0	$ 0	$ 3	$ 0
Gain (losses) included in earnings		10	9	14		0	(1)				(9)	(10)	1			3		3	3		3			(1)	(1)	0	3	2	18	10	13	43	36	8	3	13	5	1	(2)	0	(4)
Purchases		11		11							6	0														2		30		32		46						7		9
Sales		18		(20)							0															2		(9)		11		(36)
Issuances		0		0		0	0				0	0			0		0		0		0		0			0		0		0		0		0		0		0		0				0	0			0
Settlements											7	7							(3)		(24)													(19)		(19)				(3)		(2)
Purchases, sales, issuances and settlements			(1)		(4)											(29)		(29)		(175)		(399)		(1)	(9)		(118)		(129)		(1)		(3)		(11)		(13)				4					3
Transfers into Level 3				10																																						3
Transfers out of Level 3		(6)		(9)																						(125)		(125)		(109)		(109)						0		(3)
Net transfers into (out of) Level 3			(1)		(8)											1		1											(8)								6
Balance at June 30, 2011		81	87	81	87	0	0	0	0	0	8	8	10	10	1	4	1	4	0	24	0	24	0	9	9	270	419	270	419	470	530	470	530	14	24	14	24	33	31	33	31		9	0	0	3	3	0
Unrealized gains (losses) included in earnings	$ (1)				$ 0											$ 2		$ 2								$ 6	$ (14)	$ 8	$ 2	$ 4	$ 13	$ 28	$ 32	$ 22	$ 34	$ 32	$ 41	$ 1	$ (2)	$ (3)	$ (4)