Consolidated Statements Of Operations - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Change in fair value of insured derivatives:
Unrealized gains (losses) on insured derivatives		$ 0	$ 7	$ 25
Net change in fair value of insured derivatives			6	15
Net gains (losses) on financial instruments at fair value and foreign exchange		40	(86)	(78)
Net investment losses related to other-than-temporary impairments:
Net investment losses related to other-than-temporary impairments				(67)
Net gains (losses) on extinguishment of debt		30		(1)
Other net realized gains (losses)		(6)	0	4
Total revenues		189	282	280
Expenses:
Losses and loss adjustment		350	530	242
Interest		163	178	201
Total expenses		634	860	637
Income (loss) before income taxes		(445)	(578)	(357)
Provision (benefit) for income taxes		0	0	2
Net income (loss)		$ (445)	$ (578)	$ (359)
Net income (loss) per common share:
Basic		$ (8.99)	$ (9.78)	$ (4.43)
Diluted		$ (8.99)	$ (9.78)	$ (4.43)
Weighted average number of common shares outstanding:
Basic	[1]	49,472,281	59,071,843	81,014,285
Diluted		49,472,281	59,071,843	81,014,285
Non Variable Interest Entity [Member]
Premiums earned:
Scheduled premiums earned		$ 64	$ 59	$ 68
Refunding premiums earned		10	14	17
Premiums earned (net of ceded premiums of $16, $5 and $5)		74	73	85
Net investment income		62	76	114
Net realized investment gains (losses)		5	48	130
Fees and reimbursements		7	2	1
Change in fair value of insured derivatives:
Realized gains (losses) and other settlements on insured derivatives		0	(1)	(10)
Unrealized gains (losses) on insured derivatives		0	7	25
Net change in fair value of insured derivatives		0	6	15
Net gains (losses) on financial instruments at fair value and foreign exchange		40	(86)	(78)
Net investment losses related to other-than-temporary impairments:
Other-than-temporary impairments recognized in accumulated other comprehensive income (loss)		0	0	(67)
Net investment losses related to other-than-temporary impairments		0	0	(67)
Net gains (losses) on extinguishment of debt		30	0	(1)
Other net realized gains (losses)		(6)	0	4
Expenses:
Losses and loss adjustment		350	530	242
Amortization of deferred acquisition costs		6	10	11
Operating		91	87	92
Interest		163	178	201
Variable Interest Entity Primary Beneficiary [Member]
Premiums earned:
Net investment income		0	18	34
Change in fair value of insured derivatives:
Net gains (losses) on financial instruments at fair value and foreign exchange		(8)	108	105
Net investment losses related to other-than-temporary impairments:
Other net realized gains (losses)		(15)	37	(62)
Expenses:
Operating		6	5	9
Interest		$ 18	$ 50	$ 82

[1] Includes 0.9 million, 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 years ended December 31, 2021, 2020 and 2019, respectively.