Consolidated Statements Of Operations (Unaudited) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Change in fair value of insured derivatives:
Unrealized gains (losses) on insured derivatives				$ 0	$ 14
Net change in fair value of insured derivatives			$ (1)		13
Net gains (losses) on financial instruments at fair value and foreign exchange		$ 24	(26)	(39)	(4)
Net investment losses related to other-than-temporary impairments:
Net investment losses related to other-than-temporary impairments			(9)		(37)
Other net realized gains (losses)			1		2
Total revenues		114	30	108	80
Expenses:
Losses and loss adjustment		136	140	379	102
Interest		45	52	92	104
Total expenses		220	237	547	306
Income (loss) before income taxes		(106)	(207)	(439)	(226)
Provision (benefit) for income taxes		0	0	0	2
Net income (loss)		$ (106)	$ (207)	$ (439)	$ (228)
Net income (loss) per common share:
Basic		$ (1.69)	$ (2.45)	$ (6.51)	$ (2.68)
Diluted		$ (1.69)	$ (2.45)	$ (6.51)	$ (2.68)
Weighted average number of common shares outstanding:
Basic	[1]	62,605,656	84,275,261	67,347,335	84,911,215
Diluted		62,605,656	84,275,261	67,347,335	84,911,215
Non Variable Interest Entity [Member]
Premiums earned:
Scheduled premiums earned		$ 15	$ 17	$ 31	$ 35
Refunding premiums earned		4	5	8	10
Premiums earned (net of ceded premiums of $1, $1, $2 and $2)		19	22	39	45
Net investment income		20	30	43	62
Fees and reimbursements		0	1	0	1
Change in fair value of insured derivatives:
Realized gains (losses) and other settlements on insured derivatives		0	(1)	0	(1)
Unrealized gains (losses) on insured derivatives		0	0	0	14
Net change in fair value of insured derivatives		0	(1)	0	13
Net gains (losses) on financial instruments at fair value and foreign exchange		24	(26)	(39)	(4)
Net investment losses related to other-than-temporary impairments:
Other-than-temporary impairments recognized in accumulated other comprehensive income (loss)		0	(9)	0	(37)
Net investment losses related to other-than-temporary impairments		0	(9)	0	(37)
Other net realized gains (losses)		0	1	0	2
Expenses:
Losses and loss adjustment		136	140	379	102
Amortization of deferred acquisition costs		3	2	5	6
Operating		22	19	40	45
Interest		45	52	92	104
Variable Interest Entity Primary Beneficiary [Member]
Premiums earned:
Net investment income		5	10	13	20
Change in fair value of insured derivatives:
Net gains (losses) on financial instruments at fair value and foreign exchange		23	18	38	36
Net investment losses related to other-than-temporary impairments:
Other net realized gains (losses)		23	(16)	14	(58)
Expenses:
Operating		1	1	3	4
Interest		$ 13	$ 23	$ 28	$ 45

[1] Includes 0.9 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 June 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 six months ended June 30, 2020 and 2019, respectively.