Schedule II (Condensed Balance Sheets) (Detail) - USD ($) $ / shares in Units, $ in Millions	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Assets [Abstract]
Cash and cash equivalents	$ 280	$ 146	$ 187	$ 522
Total assets	8,076	9,095	11,137
Liabilities:
Long-term debt	2,249	2,121
Total liabilities	6,944	7,670
Equity:
Preferred stock, par value $1 per share; authorized shares--10,000,000; issued and outstanding--none	0	0
Common stock, par value $1 per share; authorized shares--400,000,000; issued shares-- 283,625,689 and 283,717,973	284	284
Additional paid-in capital	3,025	3,171
Retained earnings	966	1,095
Cumulative changes in instrument-specific credit risk of liabilities elected under the fair value option	(156)	(19)	(128)	(61)
Treasury stock, at cost-- 193,803,976 and 192,233,526 shares	(3,000)	(3,118)
Total shareholders' equity of MBIA Inc.	1,119	1,413
Total liabilities and equity	8,076	9,095
Fixed-maturity securities held as available-for-sale, amortized cost	$ 3,817	$ 4,438
Preferred stock, par value	$ 1	$ 1
Preferred stock, authorized shares	10,000,000	10,000,000
Preferred stock, issued	0	0
Preferred stock, outstanding	0	0
Common stock, par value	$ 1	$ 1
Common stock, authorized shares	400,000,000	400,000,000
Common stock, issued shares	283,625,689	283,717,973
Treasury stock, shares	193,803,976	192,233,526
Parent Company [Member]
Assets [Abstract]
Fixed-maturity securities held as available-for-sale, at fair value (amortized cost $815 and $590)	$ 839	$ 639
Investments carried at fair value	7	8
Investments pledged as collateral, at fair value (amortized cost $49 and $155)	46	148
Short-term investments held as available-for-sale, at fair value (amortized cost $83 and $283)	83	283
Other investments	0	1
Total investments	975	1,079
Cash and cash equivalents	40	10	$ 13	$ 35
Investment in wholly-owned subsidiaries	1,876	2,290
Other assets	130	144
Total assets	3,021	3,523
Liabilities:
Investment agreements	276	301
Long-term debt	577	576
Affiliate loans payable	729	772
Income taxes payable	138	237
Other liabilities	182	224
Total liabilities	1,902	2,110
Equity:
Preferred stock, par value $1 per share; authorized shares--10,000,000; issued and outstanding--none	0	0
Common stock, par value $1 per share; authorized shares--400,000,000; issued shares-- 283,625,689 and 283,717,973	284	284
Additional paid-in capital	3,025	3,171
Retained earnings	966	1,095
Cumulative changes in instrument-specific credit risk of liabilities elected under the fair value option	(156)	(19)
Treasury stock, at cost-- 193,803,976 and 192,233,526 shares	(3,000)	(3,118)
Total shareholders' equity of MBIA Inc.	1,119	1,413
Total liabilities and equity	3,021	3,523
Fixed-maturity securities held as available-for-sale, amortized cost	815	590
Investments pledged as collateral, amortized cost	49	155
Short-term investments, amortized cost	$ 83	$ 283
Preferred stock, par value	$ 1	$ 1
Preferred stock, authorized shares	10,000,000	10,000,000
Preferred stock, issued	0	0
Preferred stock, outstanding	0	0
Common stock, par value	$ 1	$ 1
Common stock, authorized shares	400,000,000	400,000,000
Common stock, issued shares	283,625,689	283,717,973
Treasury stock, shares	193,803,976	192,233,526