Consolidated Statement Of Changes In Shareholders' Equity - USD ($) $ in Millions	Total	Preferred Stock Of Subsidiary And Noncontrolling Interest [Member]	Total Shareholders' Equity Of MBIA Inc. [Member]	Common Stock [Member]	Additional Paid In Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Treasury Stock [Member]
Total equity balance at Dec. 31, 2014	$ 3,950	$ 21	$ 3,929	$ 281	$ 3,128	$ 2,858	$ 21	$ (2,359)
Balance (in common stock shares) at Dec. 31, 2014				281,352,782
Balance (in treasury stock shares) at Dec. 31, 2014								(89,409,887)
Balance (in preferred stock shares) at Dec. 31, 2014		1,315
ASU 2015-02 transition adjustment	(9)	$ (9)
Net income (loss)	180		180			180
Total other comprehensive income (loss)	(82)		(82)				(82)
Share-based compensation	5		5	$ 1	10			$ (6)
Share-based compensation (in shares)				480,836				(986,455)
Treasury shares acquired	$ (303)		(303)					$ (303)
Treasury shares acquired (in shares)	(39,900,000)							(39,906,899)
Total equity balance at Dec. 31, 2015	$ 3,741	$ 12	3,729	$ 282	3,138	3,038	(61)	$ (2,668)
Balance (in common stock shares) at Dec. 31, 2015				281,833,618
Balance (in treasury stock shares) at Dec. 31, 2015								(130,303,241)
Balance (in preferred stock shares) at Dec. 31, 2015		1,315
Net income (loss)	(338)		(338)			(338)
Total other comprehensive income (loss)	(67)		(67)				(67)
Share-based compensation	8		8	$ 2	22			$ (16)
Share-based compensation (in shares)				2,156,381				(1,925,990)
Treasury shares acquired	$ (105)		(105)					$ (105)
Treasury shares acquired (in shares)	(16,600,000)							(16,559,937)
Total equity balance at Dec. 31, 2016	$ 3,239	$ 12	3,227	$ 284	3,160	2,700	(128)	$ (2,789)
Balance (in common stock shares) at Dec. 31, 2016	283,989,999			283,989,999
Balance (in treasury stock shares) at Dec. 31, 2016	(148,789,168)							(148,789,168)
Balance (in preferred stock shares) at Dec. 31, 2016	0	1,315
Net income (loss)	$ (1,605)		(1,605)			(1,605)
Total other comprehensive income (loss)	109		109				109
Share-based compensation	7		7	$ 0	11			$ (4)
Share-based compensation (in shares)				(272,026)				(402,707)
Treasury shares acquired	$ (325)		(325)					$ (325)
Treasury shares acquired (in shares)	(43,000,000)							(43,041,651)
Total equity balance at Dec. 31, 2017	$ 1,425	$ 12	$ 1,413	$ 284	$ 3,171	$ 1,095	$ (19)	$ (3,118)
Balance (in common stock shares) at Dec. 31, 2017	283,717,973			283,717,973
Balance (in treasury stock shares) at Dec. 31, 2017	(192,233,526)							(192,233,526)
Balance (in preferred stock shares) at Dec. 31, 2017	0	1,315