Consolidated Statements Of Cash Flows - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014
Cash flows from operating activities:
Premiums, fees and reimbursements received	$ 66	$ 72
Investment income received	181	214
Insured derivative commutations and losses paid	(19)	(371)
Financial guarantee losses and loss adjustment expenses paid	(36)	(139)
Proceeds from recoveries and reinsurance	43	60
Operating and employee related expenses paid	(80)	(142)
Interest paid, net of interest converted to principal	(111)	(95)
Income taxes (paid) received	(10)	5
Net cash provided (used) by operating activities	34	(396)
Cash flows from investing activities:
Purchases of available-for-sale investments	(948)	(975)
Sales of available-for-sale investments	379	463
Paydowns and maturities of available-for-sale investments	290	255
Purchases of investments at fair value	(261)	(259)
Sales, paydowns and maturities of investments at fair value	328	343
Sales, paydowns and maturities (purchases) of short-term investments, net	305	309
Sales, paydowns and maturities of held-to-maturity investments	32	14
Paydowns and maturities of loans receivable	109	112
Consolidation of variable interest entities including cash acquired	7	0
Deconsolidation of variable interest entities	0	(1)
(Payments) proceeds for derivative settlements	54	(15)
Collateral (to) from swap counterparty	(54)	81
Capital expenditures	(2)	(3)
Other investing	47	0
Net cash provided (used) by investing activities	286	324
Cash flows from financing activities:
Proceeds from investment agreements	11	11
Principal paydowns of investment agreements	(49)	(57)
Principal paydowns of medium-term notes	(63)	(166)
Principal paydowns of variable interest entity notes	(242)	(377)
Principal paydowns of long-term debt	(11)	0
Purchases of treasury stock	(177)	0
Net cash provided (used) by financing activities	(531)	(589)
Effect of exchange rate changes on cash and cash equivalents	(4)	3
Net increase (decrease) in cash and cash equivalents	(215)	(658)
Cash and cash equivalents - beginning of period	782	1,258
Cash and cash equivalents - end of period	567	600
Reconciliation of net income (loss) to net cash provided (used) by operating activities: [Abstract]
Net income (loss)	133	376
Change in: [Abstract]
Premiums receivable	42	83
Deferred acquisition costs	24	17
Unearned premium revenue	(184)	(204)
Loss and loss adjustment expense reserves	(5)	(87)
Insurance loss recoverable	50	70
Accrued interest payable	50	51
Accrued expenses	(5)	(27)
Realized (gains) losses and other settlements on insured derivatives	0	30
Unrealized (gains) losses on insured derivatives	(100)	(815)
Net (gains) losses on financial instruments at fair value and foreign exchange	(71)	(32)
Other net realized (gains) losses	(19)	(1)
Deferred income tax provision (benefit)	70	76
Interest on variable interest entities, net	33	37
Other operating	16	30
Total adjustments to net income (loss)	(99)	(772)
Net cash provided (used) by operating activities	$ 34	$ (396)