Consolidated Statements Of Cash Flows (USD $) In Millions, unless otherwise specified	6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011
Cash flows from operating activities:
Premiums, fees and reimbursements received	$ 160	$ 189
Investment income received	316	372
Insured derivative losses and commutations paid	(463)	(389)
Financial guarantee losses and loss adjustment expenses paid	(363)	(473)
Proceeds from reinsurance and recoveries	38	70
Operating and employee related expenses paid	(232)	(173)
Interest paid	(241)	(332)
Income taxes (paid) received	(5)	55
Net cash provided (used) by operating activities	(790)	(681)
Cash flows from investing activities:
Purchase of fixed-maturity securities	(1,587)	(3,551)
Sale and redemption of fixed-maturity securities	3,376	4,939
Proceeds from paydowns on variable interest entity loans	131	157
Redemptions of held-to-maturity investments	792	105
Sale (purchase) of short-term investments, net	122	605
Sale (purchase) of other investments, net	76	33
Consolidation (deconsolidation) of variable interest entities, net	(51)	(1)
(Payments) proceeds for derivative settlements	(83)	(44)
Collateral (to) from swap counterparty	(327)
Capital expenditures	(4)	(2)
Net cash provided (used) by investing activities	2,445	2,241
Cash flows from financing activities:
Proceeds from issuance of investment agreements	33	58
Payments for drawdowns of investment agreements	(432)	(428)
Issuance of medium-term notes	13	13
Principal paydowns of medium-term notes	(42)	(107)
Principal paydowns of variable interest entity notes	(797)	(695)
Payments for securities sold under agreements to repurchase	(287)	(84)
Payments for retirement of debt	(363)	(70)
Purchase of treasury stock		(25)
Contribution from noncontrolling interest and redemption of subsidiary preferred stock, net		10
Restricted stock awards settlements	1	(1)
Net cash provided (used) by financing activities	(1,874)	(1,329)
Net increase (decrease) in cash and cash equivalents	(219)	231
Cash and cash equivalents - beginning of period	633	1,130
Cash and cash equivalents - end of period	414	1,361
Reconciliation of net income (loss) to net cash provided (used) by operating activities:
Net income (loss)	591	(1,138)
Adjustments to reconcile net income (loss) to net cash provided (used) by operating activities:
Premiums receivable	96	170
Deferred acquisition costs	27	37
Unearned premium revenue	(311)	(361)
Loss and loss adjustment expense reserves	(2)	(265)
Insurance loss recoverable	(166)	(126)
Current income taxes	(9)	60
Net investment losses related to other-than-temporary impairments	97	33
Realized losses and other settlements on insured derivatives		215
Unrealized (gains) losses on insured derivatives	(1,506)	1,307
Net Gains (Losses) on Financial Instruments at Fair Value and Foreign Exchange	86	212
Deferred income tax provision (benefit)	230	(777)
(Gains) losses on extinguishment of debt	(33)	(26)
Other operating	110	(22)
Total adjustments to net income (loss)	(1,381)	457
Net cash provided (used) by operating activities	$ (790)	$ (681)