Consolidated Statements Of Operations - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Change in fair value of insured derivatives:
Unrealized gains (losses) on insured derivatives	$ 25	$ 31	$ 0
Net change in fair value of insured derivatives			(51)
Net investment losses related to other-than-temporary impairments:
Net investment losses related to other-than-temporary impairments			(106)
Net gains (losses) on extinguishment of debt	(1)
Total revenues	280	162	433
Expenses:
Total expenses	637	458	1,094
Income (loss) before income taxes	(357)	(296)	(661)
Provision (benefit) for income taxes	2	0	944
Net income (loss)	$ (359)	$ (296)	$ (1,605)
Net income (loss) per common share:
Basic	$ (4.43)	$ (3.33)	$ (13.50)
Diluted	$ (4.43)	$ (3.33)	$ (13.50)
Weighted average number of common shares outstanding:
Basic	81,014,285	89,013,711	118,930,282
Diluted	81,014,285	89,013,711	118,930,282
Non Variable Interest Entity [Member]
Premiums earned:
Scheduled premiums earned	$ 68	$ 114	$ 107
Refunding premiums earned	17	48	94
Premiums earned (net of ceded premiums of $5, $5 and $6)	85	162	201
Net investment income	114	130	154
Fees and reimbursements	1	25	15
Change in fair value of insured derivatives:
Realized gains (losses) and other settlements on insured derivatives	(10)	(56)	(51)
Unrealized gains (losses) on insured derivatives	25	31	0
Net change in fair value of insured derivatives	15	(25)	(51)
Net gains (losses) on financial instruments at fair value and foreign exchange	52	(17)	(24)
Net investment losses related to other-than-temporary impairments:
Investment losses related to other-than-temporary impairments	0	0	(101)
Other-than-temporary impairments recognized in accumulated other comprehensive income (loss)	(67)	(5)	(5)
Net investment losses related to other-than-temporary impairments	(67)	(5)	(106)
Net gains (losses) on extinguishment of debt	(1)	3	28
Other net realized gains (losses)	4	0	31
Expenses:
Losses and loss adjustment	242	63	683
Amortization of deferred acquisition costs	11	20	23
Operating	92	71	106
Interest	201	206	197
Variable Interest Entity Primary Beneficiary [Member]
Premiums earned:
Net investment income	34	35	27
Change in fair value of insured derivatives:
Net gains (losses) on financial instruments at fair value and foreign exchange	105	25	130
Net investment losses related to other-than-temporary impairments:
Other net realized gains (losses)	(62)	(171)	28
Expenses:
Operating	9	11	10
Interest	$ 82	$ 87	$ 75