Consolidated Statements Of Operations - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Change in fair value of insured derivatives:
Unrealized gains (losses) on insured derivatives	$ (14)	$ 37
Net change in fair value of insured derivatives	(28)	28
Net gains (losses) on financial instruments at fair value and foreign exchange	(69)	30
Investment losses related to other-than-temporary impairments:
Net investment losses related to other-than-temporary impairments	(1)	0
Net gains (losses) on extinguishment of debt	2
Other net realized gains (losses)	(1)	20
Total revenues	32	219
Expenses:
Losses and loss adjustment	22	(6)
Interest	50	50
Total expenses	133	106
Income (loss) before income taxes	(101)	113
Provision (benefit) for income taxes	(23)	44
Net income (loss)	$ (78)	$ 69
Net income (loss) per common share:
Basic	$ (0.58)	$ 0.37
Diluted	$ (0.58)	$ 0.37
Weighted average number of common shares outstanding:
Basic	135,814,835	181,735,876
Diluted	135,814,835	182,736,415
Non Variable Interest Entity [Member]
Premiums earned:
Scheduled premiums earned	$ 45	$ 55
Refunding premiums earned	30	46
Premiums earned (net of ceded premiums of $2 and $4)	75	101
Net investment income	39	37
Fees and reimbursements	1	1
Change in fair value of insured derivatives:
Realized gains (losses) and other settlements on insured derivatives	(14)	(9)
Unrealized gains (losses) on insured derivatives	(14)	37
Net change in fair value of insured derivatives	(28)	28
Net gains (losses) on financial instruments at fair value and foreign exchange	(69)	30
Investment losses related to other-than-temporary impairments:
Net investment losses related to other-than-temporary impairments	(1)	0
Net gains (losses) on extinguishment of debt	2	0
Other net realized gains (losses)	(1)	20
Expenses:
Losses and loss adjustment	22	(6)
Amortization of deferred acquisition costs	10	13
Operating	35	35
Interest	50	50
Variable Interest Entity Primary Beneficiary [Member]
Premiums earned:
Net investment income	15	12
Change in fair value of insured derivatives:
Net gains (losses) on financial instruments at fair value and foreign exchange	(1)	(10)
Expenses:
Operating	4	4
Interest	$ 12	$ 10