Consolidated Statements Of Operations (Unaudited) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2020	Mar. 31, 2019
Change in fair value of insured derivatives:
Unrealized gains (losses) on insured derivatives		$ 0	$ 14
Net investment losses related to other-than-temporary impairments:
Total revenues		(6)	50
Expenses:
Total expenses		327	69
Income (loss) before income taxes		(333)	(19)
Provision (benefit) for income taxes		0	2
Net income (loss)		$ (333)	$ (21)
Net income (loss) per common share:
Basic		$ (4.62)	$ (0.24)
Diluted		$ (4.62)	$ (0.24)
Weighted average number of common shares outstanding:
Basic	[1]	72,089,016	85,554,236
Diluted	[1]	72,089,016	85,554,236
Non Variable Interest Entity [Member]
Premiums earned:
Scheduled premiums earned		$ 16	$ 18
Refunding premiums earned		4	5
Premiums earned (net of ceded premiums of $1 and $1)		20	23
Net investment income		23	32
Change in fair value of insured derivatives:
Unrealized gains (losses) on insured derivatives		0	14
Net gains (losses) on financial instruments at fair value and foreign exchange		(63)	22
Net investment losses related to other-than-temporary impairments:
Investment losses related to other-than-temporary impairments		0	0
Other-than-temporary impairments recognized in accumulated other comprehensive income (loss)		0	(28)
Net investment losses related to other-than-temporary impairments		0	(28)
Other net realized gains (losses)		0	1
Expenses:
Losses and loss adjustment		243	(38)
Amortization of deferred acquisition costs		2	4
Operating		18	26
Interest		47	52
Variable Interest Entity Primary Beneficiary [Member]
Premiums earned:
Net investment income		8	10
Change in fair value of insured derivatives:
Net gains (losses) on financial instruments at fair value and foreign exchange		15	18
Net investment losses related to other-than-temporary impairments:
Other net realized gains (losses)		(9)	(42)
Expenses:
Operating		2	3
Interest		$ 15	$ 22

[1] Includes 0.9 million of participating securities that met the service condition and were eligible to receive nonforfeitable dividends or dividend equivalents for each of the three months ended March 31, 2020 and 2019, respectively.