Business Segments (Summary Of Company's Segment Results) (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Segment Reporting Information [Line Items]
Revenues	$ 644	[1]	$ 880	[1]	$ 1,038	[1]
Net change in fair value of insured derivatives	232		1,464		(2,812)
Net gains (losses) on financial instruments at fair value and foreign exchange	69		55		(99)
Net investment losses related to other-than-temporary impairments	0		(105)		(101)
Net gains (losses) on extinguishment of debt	60		0		26
Other net realized gains (losses)	(29)		7		(1)
Revenues of consolidated VIEs	233		134		392
Inter-segment revenues	0	[2]	0	[2]	0	[3]
Total revenues	1,209		2,435		(1,557)
Losses and loss adjustment	117		50		(80)
Operating	384		431		371
Interest	236		284		300
Expenses of consolidated VIEs	56		72		91
Inter-segment expenses	0	[2]	0	[2]	0	[3]
Total expenses	793		837		682
Income (loss) before income taxes	416		1,598		(2,239)
Identifiable assets	16,953		21,724		26,873
Reportable Subsegments [Member] | Asset Liability Products Business [Member]
Segment Reporting Information [Line Items]
Revenues	34	[4]	53	[4]	90	[4]
Net gains (losses) on financial instruments at fair value and foreign exchange	(23)		(176)		(276)
Net investment losses related to other-than-temporary impairments	0		(56)		(31)
Net gains (losses) on extinguishment of debt	22		2		24
Other net realized gains (losses)	0		1		4
Revenues of consolidated VIEs	0		0		11
Inter-segment revenues	(10)	[5]	(10)	[5]	(19)	[5]
Total revenues	23		(186)		(197)
Operating	2		5		3
Interest	76		95		109
Expenses of consolidated VIEs	0		0		2
Inter-segment expenses	7	[5]	19	[5]	29	[5]
Total expenses	85		119		143
Income (loss) before income taxes	(62)		(305)		(340)
Identifiable assets	1,468		1,877		3,752
Reportable Subsegments [Member] | Conduits [Member]
Segment Reporting Information [Line Items]
Revenues	0	[4]	0	[4]	0	[4]
Net gains (losses) on financial instruments at fair value and foreign exchange	0		0		0
Net investment losses related to other-than-temporary impairments	0		0		0
Net gains (losses) on extinguishment of debt	0		0		0
Other net realized gains (losses)	0		0		0
Revenues of consolidated VIEs	10		63		20
Inter-segment revenues	(9)	[5]	(2)	[5]	(4)	[5]
Total revenues	1		61		16
Operating	0		0		0
Interest	0		0		0
Expenses of consolidated VIEs	6		13		19
Inter-segment expenses	26	[5]	97	[5]	66	[5]
Total expenses	32		110		85
Income (loss) before income taxes	(31)		(49)		(69)
Identifiable assets	178		694		1,531
Intersubsegment Eliminations [Member]
Segment Reporting Information [Line Items]
Revenues	0	[4]	0	[4]	0	[4]
Net gains (losses) on financial instruments at fair value and foreign exchange	0		0		0
Net investment losses related to other-than-temporary impairments	0		0		0
Net gains (losses) on extinguishment of debt	0		0		0
Other net realized gains (losses)	0		0		0
Revenues of consolidated VIEs	0		0		0
Inter-segment revenues	7	[5]	(2)	[5]	0	[5]
Total revenues	7		(2)		0
Operating	0		0		0
Interest	0		0		0
Expenses of consolidated VIEs	0		0		0
Inter-segment expenses	0	[5]	0	[5]	0	[5]
Total expenses	0		0		0
Income (loss) before income taxes	7		(2)		0
Identifiable assets	1		(32)		(80)
U S Public Finance Insurance [Member]
Segment Reporting Information [Line Items]
Losses and loss adjustment	105
Advisory Services [Member]
Segment Reporting Information [Line Items]
Losses and loss adjustment					0
Operating Segments [Member] | U S Public Finance Insurance [Member]
Segment Reporting Information [Line Items]
Revenues	425	[1]	548	[1]	599	[1]
Net change in fair value of insured derivatives	3		1		2
Net gains (losses) on financial instruments at fair value and foreign exchange	29		121		96
Net investment losses related to other-than-temporary impairments	0		0		0
Net gains (losses) on extinguishment of debt	0		0		0
Other net realized gains (losses)	(29)		0		(31)
Revenues of consolidated VIEs	0		0		0
Inter-segment revenues	90	[2]	168	[2]	79	[3]
Total revenues	518		838		745
Losses and loss adjustment	105		21		4
Operating	66		124		52
Interest	0		0		0
Expenses of consolidated VIEs	0		0		0
Inter-segment expenses	96	[2]	124	[2]	114	[3]
Total expenses	267		269		170
Income (loss) before income taxes	251		569		575
Identifiable assets	6,056		6,887		7,848
Operating Segments [Member] | Structured Finance And International Insurance [Member]
Segment Reporting Information [Line Items]
Revenues	150	[1]	243	[1]	319	[1]
Net change in fair value of insured derivatives	229		1,463		(2,814)
Net gains (losses) on financial instruments at fair value and foreign exchange	28		93		58
Net investment losses related to other-than-temporary impairments	0		(45)		(62)
Net gains (losses) on extinguishment of debt	0		0		0
Other net realized gains (losses)	0		1		1
Revenues of consolidated VIEs	233		71		361
Inter-segment revenues	78	[2]	45	[2]	91	[3]
Total revenues	718		1,871		(2,046)
Losses and loss adjustment	12		29		(84)
Operating	108		147		166
Interest	112		132		133
Expenses of consolidated VIEs	50		59		70
Inter-segment expenses	136	[2]	208	[2]	124	[3]
Total expenses	418		575		409
Income (loss) before income taxes	300		1,296		(2,455)
Identifiable assets	11,696		17,264		19,985
Operating Segments [Member] | Advisory Services [Member]
Segment Reporting Information [Line Items]
Revenues	16	[1]	21	[1]	26	[1]
Net change in fair value of insured derivatives	0		0		0
Net gains (losses) on financial instruments at fair value and foreign exchange	1		(1)		0
Net investment losses related to other-than-temporary impairments	0		0		0
Net gains (losses) on extinguishment of debt	0		0		0
Other net realized gains (losses)	0		0		0
Revenues of consolidated VIEs	0		0		0
Inter-segment revenues	26	[2]	34	[2]	41	[3]
Total revenues	43		54		67
Losses and loss adjustment	0		0
Operating	53		46		58
Interest	0		0		0
Expenses of consolidated VIEs	0		0		0
Inter-segment expenses	7	[2]	13	[2]	6	[3]
Total expenses	60		59		64
Income (loss) before income taxes	(17)		(5)		3
Identifiable assets	44		46		53
Operating Segments [Member] | Corporate Operations [Member]
Segment Reporting Information [Line Items]
Revenues	19	[1]	15	[1]	4	[1]
Net change in fair value of insured derivatives	0		0		0
Net gains (losses) on financial instruments at fair value and foreign exchange	34		18		23
Net investment losses related to other-than-temporary impairments	0		(4)		(8)
Net gains (losses) on extinguishment of debt	0		(2)		0
Other net realized gains (losses)	0		5		25
Revenues of consolidated VIEs	(10)		0		0
Inter-segment revenues	71	[2]	176	[2]	152	[3]
Total revenues	114		208		196
Losses and loss adjustment	0		0		0
Operating	155		109		92
Interest	48		57		58
Expenses of consolidated VIEs	0		0		0
Inter-segment expenses	11	[2]	14	[2]	22	[3]
Total expenses	214		180		172
Income (loss) before income taxes	(100)		28		24
Identifiable assets	1,265		828		829
Operating Segments [Member] | Wind Down Operations [Member]
Segment Reporting Information [Line Items]
Revenues	34	[1],[4]	53	[1],[4]	90	[1],[4]
Net change in fair value of insured derivatives	0		0		0
Net gains (losses) on financial instruments at fair value and foreign exchange	(23)		(176)		(276)
Net investment losses related to other-than-temporary impairments	0		(56)		(31)
Net gains (losses) on extinguishment of debt	22		2		24
Other net realized gains (losses)	0		1		4
Revenues of consolidated VIEs	10		63		31
Inter-segment revenues	(12)	[2],[5]	(14)	[2],[5]	(23)	[3],[5]
Total revenues	31		(127)		(181)
Losses and loss adjustment	0		0		0
Operating	2		5		3
Interest	76		95		109
Expenses of consolidated VIEs	6		13		21
Inter-segment expenses	33	[2],[5]	116	[2],[5]	95	[3],[5]
Total expenses	117		229		228
Income (loss) before income taxes	(86)		(356)		(409)
Identifiable assets	1,647		2,539		5,203
Intersegment Elimination [Member]
Segment Reporting Information [Line Items]
Revenues	0	[1]	0	[1]	0	[1]
Net change in fair value of insured derivatives	0		0		0
Net gains (losses) on financial instruments at fair value and foreign exchange	0		0		0
Net investment losses related to other-than-temporary impairments	0		0		0
Net gains (losses) on extinguishment of debt	38	[6]	0		2
Other net realized gains (losses)	0		0		0
Revenues of consolidated VIEs	0		0		0
Inter-segment revenues	(253)	[2]	(409)	[2]	(340)	[3]
Total revenues	(215)		(409)		(338)
Losses and loss adjustment	0		0		0
Operating	0		0		0
Interest	0		0		0
Expenses of consolidated VIEs	0		0		0
Inter-segment expenses	(283)	[2]	(475)	[2]	(361)	[3]
Total expenses	(283)		(475)		(361)
Income (loss) before income taxes	68		66		23
Identifiable assets	$ (3,755)	[7]	$ (5,840)	[8]	$ (7,045)	[9]

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

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

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

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

[6] Represents the gain on the debt received as consideration in connection with the BofA Settlement Agreement.

[7] Consists of intercompany reinsurance balances, repurchase agreements and deferred income taxes.

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

[9] Consists of intercompany reinsurance balances, repurchase agreements and loans.