Consolidated Statements Of Changes In Shareholders' Equity (Unaudited) - USD ($) $ in Millions	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Treasury Stock [Member]	Total Shareholders' Equity Of MBIA Inc. [Member]	Preferred Stock [Member]
Total equity balance at Dec. 31, 2018		$ 284	$ 3,025	$ 966	$ (156)	$ (3,000)	$ 1,119
Balance (in common stock shares) at Dec. 31, 2018		283,625,689
Balance (in treasury stock shares) at Dec. 31, 2018						(193,803,976)
ASU 2016-13 transition adjustment | ASU 2016-13 [Member]				0
Net income (loss)	$ (21)			(21)
Other comprehensive income (loss)	86				86
Treasury shares acquired under share repurchase program						$ (4)
Treasury shares acquired under share repurchase program (in shares)						(487,606)
Other						$ 37
Others (in shares)						845,414
Period change			(29)				69
Total equity balance at Mar. 31, 2019	1,201		2,996	945	(70)	$ (2,967)	1,188	$ 13
Balance (in common stock shares) at Mar. 31, 2019		283,625,689
Balance (in treasury stock shares) at Mar. 31, 2019						(193,446,168)
Balance (in preferred stock shares) at Mar. 31, 2019								1,315
Total equity balance at Dec. 31, 2019	$ 839	$ 283	2,999	607	(2)	$ (3,061)	826
Balance (in common stock shares) at Dec. 31, 2019	283,433,401	283,433,401
Balance (in treasury stock shares) at Dec. 31, 2019	(204,000,108)					(204,000,108)
ASU 2016-13 transition adjustment | ASU 2016-13 [Member]				(42)
Net income (loss)	$ (333)			(333)
Other comprehensive income (loss)	93				93
Treasury shares acquired under share repurchase program						$ (65)
Treasury shares acquired under share repurchase program (in shares)						(8,082,756)
Other						$ 43
Others (in shares)						809,869
Period change			(38)				(342)
Total equity balance at Mar. 31, 2020	$ 497		$ 2,961	$ 232	$ 91	$ (3,083)	$ 484	$ 13
Balance (in common stock shares) at Mar. 31, 2020	283,433,401	283,433,401
Balance (in treasury stock shares) at Mar. 31, 2020	(211,272,995)					(211,272,995)
Balance (in preferred stock shares) at Mar. 31, 2020	0							1,315