Consolidated Statement Of Changes In Shareholders' Equity (USD $) In Millions, except Share data	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 of Subsidiary [Member]	Total
Beginning Balance at Dec. 31, 2010	$ 275	$ 3,064	$ 2,124	$ (406)	$ (2,225)	$ 2,832	$ 14	$ 2,832
Beginning Balance (in shares) at Dec. 31, 2010	274,719,578				(74,973,978)		1,426
Comprehensive income (loss):
Net income (loss)			(1,138)			(1,138)		(1,138)
Other comprehensive income (loss):
Change in unrealized gains and losses on investments net of tax of $93				217		217
Portion of other-than-temporary impairment losses recognized in other comprehensive loss, net of tax of $13				24		24
Change in fair value of derivative instruments net of tax of $4				6		6
Change in foreign currency translation net of tax of $5				(36)		(36)
Other comprehensive income (loss)						211
Total comprehensive income (loss)						(927)
Share-based compensation, net of tax of $4 (in shares)	202,773				(146,172)
Share-based compensation, net of tax of $4		2			(1)	1
Treasury shares acquired under share repurchase program (in shares)					(3,021,722)
Treasury shares acquired under share repurchase program					(25)	(25)
Preferred shares of subsidiary acquired (in shares)							(41)
Preferred shares of subsidiary acquired							(1)
Change in noncontrolling interest in subsidiary							11
Significant Accounting Policies
Change in unrealized gains and losses and other-than-temporary impairments on investments arising during the period, net of taxes								251
Reclassification adjustment, net of taxes								(10)
Change in net unrealized gains and losses and other-than-temporary impairment losses, net of taxes								241
Ending Balance at Jun. 30, 2011	$ 275	$ 3,066	$ 986	$ (195)	$ (2,251)	$ 1,881	$ 24	$ 1,881
Ending Balance (in shares) at Jun. 30, 2011	274,922,351				(78,141,872)		1,385