Consolidated Statements Of Cash Flows (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Cash flows from operating activities:
Premiums, fees and reimbursements received	$ 30	$ 54
Investment income received	110	115
Insured derivative commutations and losses paid	(343)	0
Financial guarantee losses and loss adjustment expenses paid	(86)	(115)
Proceeds from recoveries and reinsurance	20	13
Operating and employee related expenses paid	(111)	(84)
Interest paid, net of interest converted to principal	(48)	(61)
Income taxes (paid) received	4	0
Net cash provided (used) by operating activities	(424)	(78)
Cash flows from investing activities:
Purchases of available-for-sale investments	(325)	(471)
Sales of available-for-sale investments	16	620
Paydowns and maturities of available-for-sale investments	135	148
Purchases of investments at fair value	(386)	(87)
Sales, paydowns and maturities of investments at fair value	452	151
Sales, paydowns and maturities (purchases) of short-term investments, net	219	(103)
Sales, paydowns and maturities of held-to-maturity investments	8	4
Paydowns and maturities of loans	55	69
Consolidation (deconsolidation) of variable interest entities, net	(1)	0
(Payments) proceeds for derivative settlements	(8)	(31)
Collateral (to) from swap counterparty	46	23
Capital expenditures	(1)	0
Net cash provided (used) by investing activities	210	323
Cash flows from financing activities:
Proceeds from investment agreements	6	8
Principal paydowns of investment agreements	(20)	(39)
Principal paydowns of medium-term notes	(28)	(23)
Principal paydowns of variable interest entity notes	(270)	(246)
Payments for retirement of debt	0	(1)
Net cash provided (used) by financing activities	(312)	(301)
Effect of exchange rate changes on cash and cash equivalents	1	0
Net increase (decrease) in cash and cash equivalents	(525)	(56)
Cash and cash equivalents - beginning of period	1,258	990
Cash and cash equivalents - end of period	733	934
Reconciliation of net income (loss) to net cash provided (used) by operating activities: [Abstract]
Net income (loss)	256	164
Change in: [Abstract]
Premiums receivable	41	44
Deferred acquisition costs	10	12
Unearned premium revenue	(107)	(130)
Loss and loss adjustment expense reserves	(39)	(68)
Insurance loss recoverable	23	(229)
Accrued interest payable	27	2
Accrued expenses	(63)	57
Realized (gains) losses and other settlements on insured derivatives	30	0
Unrealized (gains) losses on insured derivatives	(838)	73
Net (gains) losses on financial instruments at fair value and foreign exchange	52	(96)
Deferred income tax provision (benefit)	148	53
Interest on variable interest entities, net	18	24
Other operating	18	16
Total adjustments to net income (loss)	(680)	(242)
Net cash provided (used) by operating activities	$ (424)	$ (78)