Business Segments (Summary Of Segments Within Wind-Down Operations) (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
Segment Reporting Information [Line Items]
Total revenues	$ 2,435		$ (1,557)		$ 894
Total expenses	837		682		989
Income (loss) before income taxes	1,598		(2,239)		(95)
Identifiable assets	21,724		26,873		32,279
Net gains (losses) on extinguishment of debt	49		26		60
Non Variable Interest Entities [Member]
Segment Reporting Information [Line Items]
Revenues	880	[1]	1,038	[1]	1,211	[2]
Net gains (losses) on financial instruments at fair value and foreign exchange	55		(99)		88
Net investment losses related to other-than-temporary impairments	(105)		(101)		(64)
Net gains (losses) on extinguishment of debt			26		35
Other net realized gains (losses)	7		(1)		29
Operating	431		371		349
Interest	284		300		325
Variable Interest Entity [Member]
Segment Reporting Information [Line Items]
Identifiable assets	8,300		10,900
Net gains (losses) on financial instruments at fair value and foreign exchange	18		59		342
Net gains (losses) on extinguishment of debt	49				25
Other net realized gains (losses)			263		(76)
Revenues of consolidated VIEs	134		392		364
Interest	55		62		59
Expenses of consolidated VIEs	72		91		83
Asset/Liability Products [Member]
Segment Reporting Information [Line Items]
Inter-segment revenues	(10)	[3]	(19)	[3]	(13)	[3]
Total revenues	(186)		(197)		40
Inter-segment expenses	19	[3]	29	[3]	58	[3]
Total expenses	119		143		188
Income (loss) before income taxes	(305)		(340)		(148)
Identifiable assets	1,877		3,752		5,125
Asset/Liability Products [Member] | Non Variable Interest Entities [Member]
Segment Reporting Information [Line Items]
Revenues	53	[4]	90	[4]	109	[4]
Net gains (losses) on financial instruments at fair value and foreign exchange	(176)		(276)		(76)
Net investment losses related to other-than-temporary impairments	(56)		(31)		(59)
Net gains (losses) on extinguishment of debt	2		24		35
Other net realized gains (losses)	1		4
Operating	5		3		5
Interest	95		109		125
Asset/Liability Products [Member] | Variable Interest Entity [Member]
Segment Reporting Information [Line Items]
Revenues of consolidated VIEs			11		44
Expenses of consolidated VIEs			2
Conduits [Member]
Segment Reporting Information [Line Items]
Inter-segment revenues	(2)	[3]	(4)	[3]	(4)	[3]
Total revenues	61		16		52
Inter-segment expenses	97	[3]	66	[3]	3	[3]
Total expenses	110		85		21
Income (loss) before income taxes	(49)		(69)		31
Identifiable assets	694		1,531		1,565
Conduits [Member] | Non Variable Interest Entities [Member]
Segment Reporting Information [Line Items]
Revenues					4	[4]
Operating					(1)
Conduits [Member] | Variable Interest Entity [Member]
Segment Reporting Information [Line Items]
Revenues of consolidated VIEs	63		20		52
Expenses of consolidated VIEs	13		19		19
Eliminations [Member]
Segment Reporting Information [Line Items]
Inter-segment revenues	(2)	[3]			(1)	[3]
Total revenues	(2)				(1)
Inter-segment expenses					(1)	[3]
Total expenses					(1)
Income (loss) before income taxes	(2)
Identifiable assets	(32)		(80)		(258)
Wind-Down Operations [Member]
Segment Reporting Information [Line Items]
Inter-segment revenues	(14)	[3],[5]	(23)	[3],[6]	(18)	[3],[7]
Total revenues	(127)		(181)		91
Inter-segment expenses	116	[3],[5]	95	[3],[8]	60	[3],[7]
Total expenses	229		228		208
Income (loss) before income taxes	(356)		(409)		(117)
Identifiable assets	2,539		5,203		6,432
Wind-Down Operations [Member] | Non Variable Interest Entities [Member]
Segment Reporting Information [Line Items]
Revenues	53	[1],[4]	90	[1],[4]	113	[2],[4]
Net gains (losses) on financial instruments at fair value and foreign exchange	(176)		(276)		(76)
Net investment losses related to other-than-temporary impairments	(56)		(31)		(59)
Net gains (losses) on extinguishment of debt	2		24		35
Other net realized gains (losses)	1		4
Operating	5		3		4
Interest	95		109		125
Wind-Down Operations [Member] | Variable Interest Entity [Member]
Segment Reporting Information [Line Items]
Revenues of consolidated VIEs	63		31		96
Expenses of consolidated VIEs	$ 13		$ 21		$ 19

[1] Represents the sum of third-party financial guarantee net premiums earned, net investment income, insurance-related fees and reimbursements, investment management fees and other fees.

[2] Represents the sum of third-party financial guarantee net premiums earned, net investment income, insurance-related fees and reimbursements, investment management fees and other fees.

[3] Represents intercompany asset management fees and expenses plus intercompany interest income and expense pertaining to intercompany debt.

[4] Represents the sum of third-party interest income, investment management services fees and other fees.

[5] Represents intercompany premium income and expense, intercompany asset management fees and expenses, intercompany interest income, expenses pertaining to intercompany receivables and payables and intercompany loans.

[6] Represents intercompany premium income and expense, intercompany asset management fees and expenses, and intercompany interest income and expense pertaining to intercompany receivables and payables.

[7] Represents intercompany premium income and expense, intercompany asset management fees and expenses, and intercompany interest income and expense pertaining to intercompany receivables and payables.

[8] Consists of intercompany reinsurance balances, repurchase agreements, deferred taxes, and loans.