Consolidated Statements Of Cash Flows (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Cash flows from operating activities:
Premiums, fees and reimbursements received	$ 281	$ 397	$ 533
Investment income received	594	898	997
Insured derivative losses and commutations paid	(464)	(2,476)	(895)
Financial guarantee losses and loss adjustment expenses paid	(895)	(1,029)	(1,545)
Proceeds from reinsurance and recoveries	263	300	398
Operating and employee related expenses paid	(400)	(312)	(274)
Interest paid, net of interest converted to principal	(400)	(479)	(574)
Income taxes (paid) received	(6)	74	414
Net cash provided (used) by operating activities	(1,027)	(2,627)	(946)
Cash flows from investing activities:
Purchase of fixed-maturity securities	(4,463)	(7,744)	(9,967)
Sale and redemption of fixed-maturity securities	6,873	11,321	11,896
Proceeds from paydowns on variable interest entity loans	276	291	860
Purchase of held-to-maturity investments			(157)
Redemptions of held-to-maturity investments	1,014	196	756
Sale (purchase) of short-term investments, net	1,012	680	662
Sale (purchase) of other investments, net	114	73	53
Purchase of non-controlling interest in an affiliate, net of cash received			(27)
Consolidation (deconsolidation) of variable interest entities, net	(51)	(432)	754
(Payments) proceeds for derivative settlements	(288)	(373)	(216)
Collateral (to) from swap counterparty	(285)		166
Capital expenditures	(7)	(5)	(5)
Disposal of capital assets			3
Net cash provided (used) by investing activities	4,195	4,007	4,778
Cash flows from financing activities:
Proceeds from investment agreements	36	71	45
Payments for drawdowns of investment agreements	(688)	(524)	(767)
Principal paydowns of medium-term notes	(102)	(137)	(507)
Principal paydowns of variable interest entity notes	(1,229)	(1,100)	(1,793)
Payments for securities sold under agreements to repurchase	(287)	(184)	(31)
Dividends paid			(1)
Net proceeds from issuance of debt		105
Payments for retirement of debt	(540)	(65)	(393)
Purchase of treasury stock		(50)	(31)
Change in noncontrolling interest and redemption of subsidiary preferred stock, net	(2)	9	(29)
Restricted stock awards settlements, net	1	(2)	2
Net cash provided (used) by financing activities	(2,811)	(1,877)	(3,505)
Net increase (decrease) in cash and cash equivalents	357	(497)	327
Cash and cash equivalents-beginning of period	633	1,130	803
Cash and cash equivalents-end of period	990	633	1,130
Reconciliation of net income (loss) to net cash provided (used) by operating activities:
Net income (loss)	1,234	(1,319)	53
Adjustments to reconcile net income (loss) to net cash provided (used) by operating activities:
Premiums receivable	152	209	259
Deferred acquisition costs	49	61	61
Unearned premium revenue	(600)	(624)	(635)
Loss and loss adjustment expense reserves	17	(293)	(81)
Insurance loss recoverable	(602)	(514)	(769)
Current income taxes	(5)	86	501
Net investment losses related to other-than-temporary impairments	105	101	64
Realized losses and other settlements on insured derivatives			(607)
Unrealized (gains) losses on insured derivatives	(1,870)	441	607
Net (gains) losses on financial instruments at fair value and foreign exchange	(73)	40	(430)
Other net realized (gains) losses	(7)	(262)	47
Deferred income tax provision (benefit)	365	(935)	(221)
(Gains) losses on extinguishment of debt	(49)	(26)	(60)
Other operating	257	408	265
Total adjustments to net income (loss)	(2,261)	(1,308)	(999)
Net cash provided (used) by operating activities	$ (1,027)	$ (2,627)	$ (946)