Consolidated Statement Of Changes In Shareholders' Equity - USD ($) $ in Millions	Total	Preferred Stock [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, 2017		$ 12	$ 1,413	$ 284	$ 3,171	$ 1,095	$ (19)	$ (3,118)
Balance (in common stock shares) at Dec. 31, 2017				283,717,973
Balance (in treasury stock shares) at Dec. 31, 2017								(192,233,526)
Balance (in preferred stock shares) at Dec. 31, 2017		1,315
Cumulative effect of prospective application of new accounting principle | ASU 2016-01 [Member]						164	(164)
Cumulative effect of prospective application of new accounting principle | ASU 2018-02 [Member]						3	(3)
Net income (loss)	$ (98)					(98)
Total other comprehensive income (loss)	(55)						(55)
Share-based compensation, net of tax					3			$ (1)
Share-based compensation (in shares)				(148,719)				(48,452)
Treasury shares acquired								$ (14)
Treasury shares acquired (in shares)								(1,961,711)
Total equity balance at Mar. 31, 2018	1,260	$ 12	1,248	$ 284	3,174	1,164	(241)	$ (3,133)
Balance (in common stock shares) at Mar. 31, 2018				283,569,254
Balance (in treasury stock shares) at Mar. 31, 2018								(194,243,689)
Balance (in preferred stock shares) at Mar. 31, 2018		1,315
Total equity balance at Dec. 31, 2018	$ 1,132	$ 13	1,119	$ 284	3,025	966	(156)	$ (3,000)
Balance (in common stock shares) at Dec. 31, 2018	283,625,689			283,625,689
Balance (in treasury stock shares) at Dec. 31, 2018	(193,803,976)							(193,803,976)
Balance (in preferred stock shares) at Dec. 31, 2018	0	1,315
Cumulative effect of prospective application of new accounting principle | ASU 2016-01 [Member]						0	0
Cumulative effect of prospective application of new accounting principle | ASU 2018-02 [Member]						0	0
Net income (loss)	$ (17)					(17)
Total other comprehensive income (loss)	82						82
Share-based compensation, net of tax					(29)			$ 37
Share-based compensation (in shares)				0				845,414
Treasury shares acquired								$ (4)
Treasury shares acquired (in shares)								(487,606)
Total equity balance at Mar. 31, 2019	$ 1,201	$ 13	$ 1,188	$ 284	$ 2,996	$ 949	$ (74)	$ (2,967)
Balance (in common stock shares) at Mar. 31, 2019	283,625,689			283,625,689
Balance (in treasury stock shares) at Mar. 31, 2019	(193,446,168)							(193,446,168)
Balance (in preferred stock shares) at Mar. 31, 2019	0	1,315