Fair Value Of Financial Instruments (Changes In Level 3 Assets And Liabilities Measured At Fair Value On A Recurring Basis) (Details) (USD $) In Millions	3 Months Ended				9 Months Ended
	Sep. 30, 2011		Sep. 30, 2010		Sep. 30, 2011		Sep. 30, 2010
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning Balance, Fair Value Assets	$ 4,528		$ 5,270		$ 4,467		$ 1,627
Realized Gains / (Losses), Assets	(5)				(9)		(16)
Unrealized Gains / (Losses) Included in Earnings, Assets	(18)		(234)		311		60
Unrealized Gains / (Losses) Included in OCI, Assets	(45)		39		6		153
Foreign Exchange Recognized in OCI or Earnings, Assets	(13)		48		(9)		19
Purchases, Assets	126				183
Issuances, Assets	2				15
Settlements, Assets	(210)				480
Sales, Assets	(123)				170
Purchases, Issuances and Settlements, net, Assets			(669)				2,599
Transfers into Level 3, Assets	144	[1]	(323)	[1]	349	[1]	720	[1]
Transfers out of Level 3, Assets	(77)	[1]	(126)	[1]	(354)	[1]	(511)	[1]
Ending Balance, Fair Value Assets	4,309		4,651		4,309		4,651
Change in Unrealized Gains (Losses) for the Period Included in Earnings for Assets Still Held, Assets	(15)		2		357		79
Beginning Balance, Fair Value Liabilities	11,307		9,924		9,916		3,900
Realized Gains / (Losses), Liabilities	79		(519)		683		(374)
Unrealized Gains / (Losses) Included in Earnings, Liabilities	(1,191)		1,283		616		2,109
Unrealized Gains / (Losses) Included in OCI, Liabilities
Foreign Exchange Recognized in OCI or Earnings, Liabilities	(9)		49		3		29
Purchases, Liabilities
Issuances, Liabilities
Settlements, Liabilities	(286)				1,139
Sales, Liabilities	(981)				1,161
Purchases, Issuances and Settlements, net, Liabilities			134				5,207
Transfers into Level 3, Liabilities		[1]		[1]	1	[1]		[1]
Transfers out of Level 3, Liabilities		[1]		[1]		[1]		[1]
Ending Balance, Fair Value Liabilities	8,919		10,871		8,919		10,871
Change in Unrealized Gains (Losses) for the Period Included in Earnings for Assets still held, Liabilities	(798)		546		2,251		1,235
Other-Fixed Maturity Investments [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning Balance, Fair Value Assets							19
Purchases, Issuances and Settlements, net, Assets							(19)
Variable Interest Entity, Primary Beneficiary [Member] | Loans Receivable [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning Balance, Fair Value Assets	2,320		2,608		2,183
Realized Gains / (Losses), Assets
Unrealized Gains / (Losses) Included in Earnings, Assets	(36)		(167)		260		28
Foreign Exchange Recognized in OCI or Earnings, Assets			42				21
Settlements, Assets	(66)				223
Sales, Assets					2
Purchases, Issuances and Settlements, net, Assets			(540)				1,894
Ending Balance, Fair Value Assets	2,218		1,943		2,218		1,943
Change in Unrealized Gains (Losses) for the Period Included in Earnings for Assets Still Held, Assets	(36)				260
Variable Interest Entity, Primary Beneficiary [Member] | Loan Repurchase Commitments [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning Balance, Fair Value Assets	905		792		835
Realized Gains / (Losses), Assets
Unrealized Gains / (Losses) Included in Earnings, Assets	33		2		91		79
Issuances, Assets					12
Purchases, Issuances and Settlements, net, Assets							715
Ending Balance, Fair Value Assets	938		794		938		794
Change in Unrealized Gains (Losses) for the Period Included in Earnings for Assets Still Held, Assets	33		2		91		79
U.S. Treasury And Government Agency [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning Balance, Fair Value Assets			27				6
Realized Gains / (Losses), Assets
Purchases, Issuances and Settlements, net, Assets							21
Transfers out of Level 3, Assets			(27)	[1]			(27)	[1]
Foreign Governments [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning Balance, Fair Value Assets	13		12		11		12
Realized Gains / (Losses), Assets
Foreign Exchange Recognized in OCI or Earnings, Assets	(8)		1		(7)		1
Purchases, Assets	3				9
Settlements, Assets	3				2
Purchases, Issuances and Settlements, net, Assets			6				6
Transfers into Level 3, Assets					7	[1]
Transfers out of Level 3, Assets					(7)	[1]
Ending Balance, Fair Value Assets	11		19		11		19
Variable Interest Entity, Primary Beneficiary [Member] | Corporate Obligations [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning Balance, Fair Value Assets	62		129		82
Realized Gains / (Losses), Assets
Unrealized Gains / (Losses) Included in Earnings, Assets	(5)				(18)		76
Settlements, Assets	(1)				5
Purchases, Issuances and Settlements, net, Assets			7				68
Transfers into Level 3, Assets	7	[1]	(13)	[1]	11	[1]	13	[1]
Transfers out of Level 3, Assets					(7)	[1]	(8)	[1]
Ending Balance, Fair Value Assets	63		149		63		149
Change in Unrealized Gains (Losses) for the Period Included in Earnings for Assets Still Held, Assets	(2)				(2)
Corporate Obligations [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning Balance, Fair Value Assets	294		284		246		281
Realized Gains / (Losses), Assets	(1)				(2)		(1)
Unrealized Gains / (Losses) Included in OCI, Assets	(10)				(3)		31
Foreign Exchange Recognized in OCI or Earnings, Assets	(5)		3		(2)		(2)
Purchases, Assets	19				31
Settlements, Assets	(32)				65
Sales, Assets	(38)				50
Purchases, Issuances and Settlements, net, Assets			(101)				(142)
Transfers into Level 3, Assets	115	[1]	(18)	[1]	202	[1]	59	[1]
Transfers out of Level 3, Assets			(60)	[1]	(15)	[1]	(82)	[1]
Ending Balance, Fair Value Assets	342		144		342		144
Variable Interest Entity, Primary Beneficiary [Member] | Residential Mortgage-Backed Securities [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning Balance, Fair Value Assets					40		166
Realized Gains / (Losses), Assets							(1)
Unrealized Gains / (Losses) Included in Earnings, Assets					2		(253)
Unrealized Gains / (Losses) Included in OCI, Assets					3		3
Settlements, Assets					6
Sales, Assets					6
Purchases, Issuances and Settlements, net, Assets							(96)
Transfers into Level 3, Assets					2	[1]	311	[1]
Transfers out of Level 3, Assets					(20)	[1]	(52)	[1]
Ending Balance, Fair Value Assets	15		78		15		78
Change in Unrealized Gains (Losses) for the Period Included in Earnings for Assets Still Held, Assets					2
Residential Mortgage-Backed Securities [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning Balance, Fair Value Assets					41		48
Realized Gains / (Losses), Assets
Unrealized Gains / (Losses) Included in OCI, Assets					1		2
Purchases, Assets	1				2
Settlements, Assets					1
Sales, Assets					1
Purchases, Issuances and Settlements, net, Assets							(5)
Transfers into Level 3, Assets			(41)	[1]			41	[1]
Transfers out of Level 3, Assets					(41)	[1]	(45)	[1]
Ending Balance, Fair Value Assets	1		41		1		41
Variable Interest Entity, Primary Beneficiary [Member] | Residential Mortgage-Backed Non-Agency [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning Balance, Fair Value Assets	17		53
Realized Gains / (Losses), Assets
Unrealized Gains / (Losses) Included in Earnings, Assets	3
Settlements, Assets	(1)
Sales, Assets	(6)
Purchases, Issuances and Settlements, net, Assets			(5)
Transfers into Level 3, Assets	2	[1]	(30)	[1]
Ending Balance, Fair Value Assets	15		78		15		78
Change in Unrealized Gains (Losses) for the Period Included in Earnings for Assets Still Held, Assets	1
Residential Mortgage-Backed Non-Agency [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning Balance, Fair Value Assets	28		30		48		64
Realized Gains / (Losses), Assets	(1)				(2)		(3)
Unrealized Gains / (Losses) Included in OCI, Assets	1		2		11		34
Foreign Exchange Recognized in OCI or Earnings, Assets					(1)
Purchases, Assets	2				13
Settlements, Assets	(4)				14
Sales, Assets					19
Purchases, Issuances and Settlements, net, Assets			(2)				(23)
Transfers into Level 3, Assets	1	[1]	(50)	[1]	9	[1]	53	[1]
Transfers out of Level 3, Assets	(2)	[1]	(1)	[1]	(20)	[1]	(46)	[1]
Ending Balance, Fair Value Assets	25		79		25		79
Variable Interest Entity, Primary Beneficiary [Member] | Commercial Mortgage-Backed [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning Balance, Fair Value Assets	27		216		23		3
Realized Gains / (Losses), Assets
Unrealized Gains / (Losses) Included in Earnings, Assets	(1)		3		6		221
Settlements, Assets					2
Sales, Assets	(11)				12
Purchases, Issuances and Settlements, net, Assets			(20)				33
Transfers into Level 3, Assets	2	[1]	(17)	[1]	2	[1]	18	[1]
Transfers out of Level 3, Assets							(59)	[1]
Ending Balance, Fair Value Assets	17		216		17		216
Change in Unrealized Gains (Losses) for the Period Included in Earnings for Assets Still Held, Assets	(2)				3
Commercial Mortgage-Backed [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning Balance, Fair Value Assets	50		14		41		20
Realized Gains / (Losses), Assets	(2)				(2)
Unrealized Gains / (Losses) Included in OCI, Assets					2		1
Foreign Exchange Recognized in OCI or Earnings, Assets			2		1		(1)
Purchases, Assets					8
Settlements, Assets	(3)				3
Sales, Assets	(13)				14
Purchases, Issuances and Settlements, net, Assets			(1)				(5)
Transfers out of Level 3, Assets			(1)	[1]	(1)	[1]	(1)	[1]
Ending Balance, Fair Value Assets	32		14		32		14
Variable Interest Entity, Primary Beneficiary [Member] | Collateralized Debt Obligations [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning Balance, Fair Value Assets	201		327		245		42
Realized Gains / (Losses), Assets
Unrealized Gains / (Losses) Included in Earnings, Assets	(17)		(53)		(27)		(80)
Unrealized Gains / (Losses) Included in OCI, Assets	(7)				(7)
Purchases, Assets	60				60
Settlements, Assets	(1)				3
Sales, Assets	(21)				21
Purchases, Issuances and Settlements, net, Assets			37				321
Transfers into Level 3, Assets	12	[1]	(34)	[1]	48	[1]	74	[1]
Transfers out of Level 3, Assets	(21)	[1]			(89)	[1]	(12)	[1]
Ending Balance, Fair Value Assets	206		345		206		345
Change in Unrealized Gains (Losses) for the Period Included in Earnings for Assets Still Held, Assets	(14)				1
Collateralized Debt Obligations [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning Balance, Fair Value Assets	162		111		191		245
Realized Gains / (Losses), Assets	(2)				(4)		(12)
Unrealized Gains / (Losses) Included in OCI, Assets	(3)		5		25		65
Purchases, Assets	39				47
Issuances, Assets	2				3
Settlements, Assets	(79)				112
Sales, Assets	(28)				36
Purchases, Issuances and Settlements, net, Assets			(13)				(89)
Transfers into Level 3, Assets	1	[1]	(100)	[1]	49	[1]	116	[1]
Transfers out of Level 3, Assets	(25)	[1]	(2)	[1]	(96)	[1]	(124)	[1]
Ending Balance, Fair Value Assets	67		201		67		201
Variable Interest Entity, Primary Beneficiary [Member] | Other Asset-Backed [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning Balance, Fair Value Assets	73		153		81		193
Realized Gains / (Losses), Assets
Unrealized Gains / (Losses) Included in Earnings, Assets	5		(19)		(3)		(11)
Settlements, Assets					2
Sales, Assets	(6)				6
Purchases, Issuances and Settlements, net, Assets			(4)				(51)
Transfers into Level 3, Assets			(16)	[1]	2	[1]	18	[1]
Transfers out of Level 3, Assets	(1)	[1]	(26)	[1]	(1)	[1]	(29)	[1]
Ending Balance, Fair Value Assets	71		120		71		120
Change in Unrealized Gains (Losses) for the Period Included in Earnings for Assets Still Held, Assets	5				2
Other Asset-Backed [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning Balance, Fair Value Assets	331		391		350		401
Realized Gains / (Losses), Assets
Unrealized Gains / (Losses) Included in OCI, Assets	(27)		32		(26)		7
Purchases, Assets	2				11
Settlements, Assets	(9)				20
Sales, Assets					2
Purchases, Issuances and Settlements, net, Assets			(31)				(12)
Transfers into Level 3, Assets	3	[1]	(4)	[1]	16	[1]	17	[1]
Transfers out of Level 3, Assets	(28)	[1]	(9)	[1]	(57)	[1]	(26)	[1]
Ending Balance, Fair Value Assets	272		387		272		387
State And Municipal Tax-Exempt Bonds [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning Balance, Fair Value Assets	32		38		36		50
Realized Gains / (Losses), Assets							1
Unrealized Gains / (Losses) Included in OCI, Assets							1
Purchases, Assets					2
Settlements, Assets	(2)				7
Sales, Assets					1
Purchases, Issuances and Settlements, net, Assets			(2)				(16)
Ending Balance, Fair Value Assets	30		36		30		36
State And Municipal Taxable Bonds [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning Balance, Fair Value Assets	13				14
Realized Gains / (Losses), Assets	1				1
Unrealized Gains / (Losses) Included in OCI, Assets	1
Settlements, Assets	(15)				15
Perpetual Preferred Securities [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning Balance, Fair Value Assets			85				77
Realized Gains / (Losses), Assets
Unrealized Gains / (Losses) Included in OCI, Assets							9
Purchases, Issuances and Settlements, net, Assets							(1)
Transfers into Level 3, Assets	1	[1]			1	[1]
Ending Balance, Fair Value Assets	1		85		1		85
Liabilities Of Consolidated VIEs [Member] | Credit Derivatives [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning Balance, Fair Value Liabilities	920				768
Unrealized Gains / (Losses) Included in Earnings, Liabilities	(154)				(3)
Unrealized Gains / (Losses) Included in OCI, Liabilities
Purchases, Liabilities
Issuances, Liabilities
Settlements, Liabilities	(1)
Transfers into Level 3, Liabilities		[1]
Transfers out of Level 3, Liabilities		[1]				[1]
Ending Balance, Fair Value Liabilities	765				765
Change in Unrealized Gains (Losses) for the Period Included in Earnings for Assets still held, Liabilities	(154)				(3)
Credit Derivatives [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning Balance, Fair Value Liabilities	5,656		4,414		4,350		3,799
Realized Gains / (Losses), Liabilities	79		(519)		683		(366)
Unrealized Gains / (Losses) Included in Earnings, Liabilities	(777)		1,046		530		1,719
Unrealized Gains / (Losses) Included in OCI, Liabilities
Purchases, Liabilities
Issuances, Liabilities
Settlements, Liabilities	(78)				683
Purchases, Issuances and Settlements, net, Liabilities			519				308
Transfers into Level 3, Liabilities		[1]		[1]				[1]
Transfers out of Level 3, Liabilities		[1]		[1]		[1]		[1]
Ending Balance, Fair Value Liabilities	4,880		5,460		4,880		5,460
Change in Unrealized Gains (Losses) for the Period Included in Earnings for Assets still held, Liabilities	(388)		531		2,160		1,208
Interest Rate Derivatives [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning Balance, Fair Value Liabilities	(4)		(7)		(5)		(6)
Realized Gains / (Losses), Liabilities							(8)
Unrealized Gains / (Losses) Included in Earnings, Liabilities	1		4		1		7
Unrealized Gains / (Losses) Included in OCI, Liabilities
Foreign Exchange Recognized in OCI or Earnings, Liabilities			(4)
Purchases, Liabilities
Issuances, Liabilities
Transfers into Level 3, Liabilities		[1]		[1]	1	[1]		[1]
Transfers out of Level 3, Liabilities		[1]		[1]		[1]		[1]
Ending Balance, Fair Value Liabilities	(3)		(7)		(3)		(7)
Change in Unrealized Gains (Losses) for the Period Included in Earnings for Assets still held, Liabilities	5		17		6		23
Liabilities Of Consolidated VIEs [Member] | Currency Derivatives [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning Balance, Fair Value Liabilities	16				14
Unrealized Gains / (Losses) Included in Earnings, Liabilities	2				4
Unrealized Gains / (Losses) Included in OCI, Liabilities
Purchases, Liabilities
Issuances, Liabilities
Transfers into Level 3, Liabilities		[1]
Transfers out of Level 3, Liabilities		[1]				[1]
Ending Balance, Fair Value Liabilities	18				18
Change in Unrealized Gains (Losses) for the Period Included in Earnings for Assets still held, Liabilities	2				4
Currency Derivatives [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning Balance, Fair Value Liabilities			(7)				(3)
Unrealized Gains / (Losses) Included in Earnings, Liabilities			(7)				(9)
Unrealized Gains / (Losses) Included in OCI, Liabilities
Foreign Exchange Recognized in OCI or Earnings, Liabilities			(2)				(4)
Transfers into Level 3, Liabilities				[1]				[1]
Transfers out of Level 3, Liabilities				[1]				[1]
Ending Balance, Fair Value Liabilities			(16)				(16)
Change in Unrealized Gains (Losses) for the Period Included in Earnings for Assets still held, Liabilities			(10)				(22)
Medium-Term Notes [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning Balance, Fair Value Liabilities	206		109		116		110
Unrealized Gains / (Losses) Included in Earnings, Liabilities	(69)		(9)		9		6
Unrealized Gains / (Losses) Included in OCI, Liabilities
Foreign Exchange Recognized in OCI or Earnings, Liabilities	(9)		10		3		(6)
Purchases, Liabilities
Issuances, Liabilities
Transfers into Level 3, Liabilities		[1]		[1]				[1]
Transfers out of Level 3, Liabilities		[1]		[1]		[1]		[1]
Ending Balance, Fair Value Liabilities	128		110		128		110
Change in Unrealized Gains (Losses) for the Period Included in Earnings for Assets still held, Liabilities	(69)		(9)		9		6
Liabilities Of Consolidated VIEs [Member] | Variable Interest Entity Notes [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning Balance, Fair Value Liabilities	4,513		5,045		4,673
Unrealized Gains / (Losses) Included in Earnings, Liabilities	(194)		232		75		366
Unrealized Gains / (Losses) Included in OCI, Liabilities
Foreign Exchange Recognized in OCI or Earnings, Liabilities			45				39
Purchases, Liabilities
Issuances, Liabilities
Settlements, Liabilities	(207)				456
Sales, Liabilities	(981)				1,161
Purchases, Issuances and Settlements, net, Liabilities			(540)				4,377
Transfers into Level 3, Liabilities		[1]		[1]				[1]
Transfers out of Level 3, Liabilities		[1]		[1]		[1]		[1]
Ending Balance, Fair Value Liabilities	3,131		4,782		3,131		4,782
Change in Unrealized Gains (Losses) for the Period Included in Earnings for Assets still held, Liabilities	(194)				75
Derivative Contracts, Net [Member] | Liabilities Of Consolidated VIEs [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning Balance, Fair Value Liabilities			370
Unrealized Gains / (Losses) Included in Earnings, Liabilities			17				20
Unrealized Gains / (Losses) Included in OCI, Liabilities
Purchases, Issuances and Settlements, net, Liabilities			155				522
Transfers into Level 3, Liabilities				[1]				[1]
Transfers out of Level 3, Liabilities				[1]				[1]
Ending Balance, Fair Value Liabilities			542				542
Change in Unrealized Gains (Losses) for the Period Included in Earnings for Assets still held, Liabilities			$ 17				$ 20

[1] Transferred in and out at the end of the period.