Consolidated Statements Of Operations (Unaudited) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Change in fair value of insured derivatives:
Unrealized gains (losses) on insured derivatives				$ 0	$ 23
Net change in fair value of insured derivatives					13
Net gains (losses) on financial instruments at fair value and foreign exchange		$ 13	$ 44	(26)	40
Net investment losses related to other-than-temporary impairments:
Net investment losses related to other-than-temporary impairments					(37)
Net gains (losses) on extinguishment of debt			(1)		(1)
Other net realized gains (losses)			0		2
Total revenues		71	172	179	252
Expenses:
Losses and loss adjustment		48	(13)	427	89
Interest		43	50	135	154
Total expenses		129	83	676	389
Income (loss) before income taxes		(58)	89	(497)	(137)
Provision (benefit) for income taxes		0	6	0	8
Net income (loss)		$ (58)	$ 83	$ (497)	$ (145)
Net income (loss) per common share:
Basic		$ (1.11)	$ 1.00	$ (7.97)	$ (1.75)
Diluted		$ (1.11)	$ 1.00	$ (7.97)	$ (1.75)
Weighted average number of common shares outstanding:
Basic	[1]	52,588,533	78,686,542	62,391,826	82,813,523
Diluted		52,588,533	78,686,542	62,391,826	82,813,523
Non Variable Interest Entity [Member]
Premiums earned:
Scheduled premiums earned		$ 14	$ 17	$ 45	$ 52
Refunding premiums earned		2	3	10	13
Premiums earned (net of ceded premiums of $1, $1, $3 and $4)		16	20	55	65
Net investment income		16	27	59	89
Fees and reimbursements		2	0	2	1
Change in fair value of insured derivatives:
Realized gains (losses) and other settlements on insured derivatives		0	(9)	0	(10)
Unrealized gains (losses) on insured derivatives		0	9	0	23
Net change in fair value of insured derivatives		0	0	0	13
Net gains (losses) on financial instruments at fair value and foreign exchange		13	44	(26)	40
Net investment losses related to other-than-temporary impairments:
Other-than-temporary impairments recognized in accumulated other comprehensive income (loss)		0	0	0	(37)
Net investment losses related to other-than-temporary impairments		0	0	0	(37)
Net gains (losses) on extinguishment of debt		0	(1)	0	(1)
Other net realized gains (losses)		0	0	0	2
Expenses:
Losses and loss adjustment		48	(13)	427	89
Amortization of deferred acquisition costs		2	3	7	9
Operating		21	23	61	68
Interest		43	50	135	154
Variable Interest Entity Primary Beneficiary [Member]
Premiums earned:
Net investment income		5	10	18	30
Change in fair value of insured derivatives:
Net gains (losses) on financial instruments at fair value and foreign exchange		(4)	76	34	112
Net investment losses related to other-than-temporary impairments:
Other net realized gains (losses)		23	(4)	37	(62)
Expenses:
Operating		1	2	4	6
Interest		$ 14	$ 18	$ 42	$ 63

[1] Includes 1.0 million and 1.1 million of participating securities that met the service condition and were eligible to receive nonforfeitable dividends or dividend equivalents for the three months ended September 30, 2020 and 2019, respectively. Includes 0.9 million and 1.0 million of participating securities that met the service condition and were eligible to receive nonforfeitable dividends or dividend equivalents for the nine months ended September 30, 2020 and 2019, respectively.