Consolidated Statements Of Cash Flows - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Cash flows from operating activities:
Premiums, fees and reimbursements received	$ 87	$ 66
Investment income received	249	263
Insured derivative commutations and losses paid	(24)	(42)
Financial guarantee losses and loss adjustment expenses paid	(324)	(68)
Proceeds from recoveries and reinsurance	88	61
Operating and employee related expenses paid	(99)	(99)
Interest paid, net of interest converted to principal	(102)	(130)
Income taxes (paid) received	(4)	(9)
Net cash provided (used) by operating activities	(129)	42
Cash flows from investing activities:
Purchases of available-for-sale investments	(2,112)	(1,497)
Sales of available-for-sale investments	1,785	630
Paydowns and maturities of available-for-sale investments	410	463
Purchases of investments at fair value	(88)	(324)
Sales, paydowns and maturities of investments at fair value	197	447
Sales, paydowns and maturities (purchases) of short-term investments, net	90	582
Sales, paydowns and maturities of held-to-maturity investments	1,799	50
Sales, paydowns and maturities of other investments	1	0
Paydowns and maturities of loans receivable	188	172
Consolidation of variable interest entities	1	7
(Payments) proceeds for derivative settlements	(36)	33
Collateral (to) from swap counterparty	10	(64)
Capital expenditures	(1)	(3)
Other investing	(8)	47
Net cash provided (used) by investing activities	2,236	543
Cash flows from financing activities:
Proceeds from investment agreements	17	21
Principal paydowns of investment agreements	(63)	(88)
Principal paydowns of medium-term notes	(122)	(116)
Principal paydowns of variable interest entity notes	(2,136)	(392)
Principal paydowns of long-term debt	0	(11)
Purchases of treasury stock	(108)	(300)
Net cash provided (used) by financing activities	(2,412)	(886)
Effect of exchange rate changes on cash and cash equivalents	(1)	11
Net increase (decrease) in cash and cash equivalents	(306)	(290)
Cash and cash equivalents - beginning of period	522	782
Cash and cash equivalents - end of period	216	492
Reconciliation of net income (loss) to net cash provided (used) by operating activities: [Abstract]
Net income (loss)	(73)	98
Change in: [Abstract]
Premiums receivable	61	63
Deferred acquisition costs	31	35
Unearned premium revenue	(197)	(274)
Loss and loss adjustment expense reserves	(1)	(24)
Insurance loss recoverable	(98)	96
Accrued interest payable	82	78
Accrued expenses	4	0
Unrealized (gains) losses on insured derivatives	0	(121)
Net (gains) losses on financial instruments at fair value and foreign exchange	17	(29)
Other net realized (gains) losses	3	(18)
Deferred income tax provision (benefit)	(33)	50
Interest on variable interest entities, net	45	51
Other operating	30	37
Total adjustments to net income (loss)	(56)	(56)
Net cash provided (used) by operating activities	$ (129)	$ 42