Consolidated Statements Of Operations - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Revenues:
Net realized investment gains (losses)				$ (23)	$ (37)
Net gains (losses) on financial instruments at fair value and foreign exchange		$ 21	$ 25	20	51
Net gains (losses) on extinguishment of debt		0	0	1	4
Fees and reimbursements		0	0	0	4
Total revenues		8	17	38	97
Expenses:
Losses and loss adjustment		123	(12)	158	57
Interest		53	46	157	130
Total expenses		193	52	384	241
Income (loss) from continuing operations before income taxes		(185)	(35)	(346)	(144)
Provision (benefit) for income taxes		0	0	0	0
Income (loss) from continuing operations		(185)	(35)	(346)	(144)
Income (loss) from discontinued operations, net of income taxes		(1)	1	(2)	1
Net income (loss)		(186)	(34)	(348)	(143)
Less: Net income from discontinued operations attributable to noncontrolling interest		(1)	0	5	0
Net income (loss) attributable to MBIA Inc.		$ (185)	$ (34)	$ (353)	$ (143)
Net income (loss) per common share attributable to MBIA Inc. - basic and diluted
Continuing operations - basic		$ (3.93)	$ (0.68)	$ (7.1)	$ (2.88)
Continuing operations - diluted		(3.93)	(0.68)	(7.1)	(2.88)
Discontinued operations - basic		(0.01)	0.01	(0.15)	0.01
Discontinued operations - diluted		(0.01)	0.01	(0.15)	0.01
Net income (loss) per common share attributable to MBIA Inc. - basic		(3.94)	(0.67)	(7.25)	(2.87)
Net income (loss) per common share attributable to MBIA Inc. - diluted		$ (3.94)	$ (0.67)	$ (7.25)	$ (2.87)
Weighted average number of common shares outstanding:
Basic	[1]	47,009,765	49,878,191	48,654,638	49,779,681
Diluted	[1]	47,009,765	49,878,191	48,654,638	49,779,681
Non Variable Interest Entity [Member]
Revenues:
Scheduled premiums earned		$ 9	$ 10	$ 27	$ 31
Refunding premiums earned		1	1	1	6
Premiums earned (net of ceded premiums of $0, $0, $0 and $1)		10	11	28	37
Net investment income		26	24	89	67
Net realized investment gains (losses)		(13)	(13)	(23)	(37)
Net gains (losses) on financial instruments at fair value and foreign exchange		21	25	20	51
Other net realized gains (losses)		(6)	1	(5)	(18)
Expenses:
Losses and loss adjustment		123	(12)	158	57
Amortization of deferred acquisition costs		1	2	3	5
Operating		15	14	0	44
Interest		53	46	157	130
Variable Interest Entity, Primary Beneficiary [Member]
Revenues:
Net gains (losses) on financial instruments at fair value and foreign exchange		(23)	(36)	(47)	(16)
Other net realized gains (losses)		(7)	5	(25)	5
Expenses:
Operating		$ 1	$ 2	$ 9	$ 5

[1] Includes approximately 1 million of participating securities that met the service condition and were eligible to receive nonforfeitable dividends or dividend equivalents for the three and nine months ended September 30, 2023 and 2022.