Business, Developments, Risks And Uncertainties, Liquidity (Narrative) (Details) (USD $)	3 Months Ended	12 Months Ended											12 Months Ended					12 Months Ended					12 Months Ended								12 Months Ended				12 Months Ended			12 Months Ended			12 Months Ended
	Dec. 31, 2011	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2011 MBIA Insurance Corporation [Member]	Dec. 31, 2011 MBIA Corp. [Member]	Dec. 31, 2010 MBIA Corp. [Member]	Dec. 31, 2011 MBIA Inc. [Member]	Dec. 31, 2010 MBIA Inc. [Member]	Dec. 31, 2009 MBIA Inc. [Member]	Dec. 31, 2008 MBIA Inc. [Member]	Dec. 31, 2011 National [Member]	Dec. 31, 2011 During 2011 [Member]	Dec. 31, 2011 ABS CDO [Member]	Dec. 31, 2011 CRE CDO Pool Insured Gross Par [Member]	Dec. 31, 2011 CMBS Pool And CRECDO Gross Par Exposure Decrease Since 2007 [Member]	Dec. 31, 2011 ABSCDO Gross Par Exposure Decrease Since 2007 [Member] Decrease Since 2007 [Member]	Dec. 31, 2011 Maximum Amount [Member]	Dec. 31, 2011 Notional Amount Utilized [Member]	Dec. 31, 2011 Fair Value Of Collateral Pledged By National [Member]	Dec. 31, 2011 Fair Value Of Collateral Pledged By Asset Liability Products Segment [Member]	Dec. 31, 2011 Fair Value Of Collaterall Pledged [Member]	Dec. 31, 2011 Net Average Interest Rate [Member]	Dec. 31, 2010 Net Average Interest Rate [Member]	Dec. 31, 2009 Net Average Interest Rate [Member]	Dec. 31, 2011 Interest Rate [Member] MBIA Corp. [Member]	Dec. 31, 2011 Amount Outstanding [Member]	Dec. 31, 2011 Amount Outstanding [Member] MBIA Corp. [Member]	Dec. 31, 2011 Loan Repayments [Member]	Dec. 31, 2011 Loan Repayments [Member] MBIA Corp. [Member]	Dec. 31, 2011 Second-Lien RMBS Securitizations [Member]	Dec. 31, 2011 Second-Lien RMBS [Member]	Dec. 31, 2011 Maximum Amount At Inception [Member]	Dec. 31, 2011 Asset Liabilitiy Products [Member]	Dec. 31, 2011 Financial Guarantees [Member]	Dec. 31, 2011 Insured Credit Default Swaps [Member]	Dec. 31, 2011 Excluded Crecdo Pool Insured Gross Par [Member]	Dec. 31, 2011 Consolidated VIEs [Member] MBIA Insurance Corporation [Member]	Dec. 31, 2011 National [Member]	Dec. 31, 2011 CMBS Pool Insured Gross Par [Member]	Dec. 31, 2011 Total [Member] MBIA Insurance Corporation [Member]
Business Acquisition [Line Items]
Statutory capital					$ 2,300,000,000																																		$ 2,800,000,000
Estimated insurance recoveries, after income taxes	2,000,000,000	2,000,000,000	1,600,000,000
Estimated Insurance Recoveries																																3,100,000,000
Percentage of recognized estimated recoveries in relationship to consolidated total shareholder's equity	119.00%	119.00%	58.00%
Percentage of ineligible mortgage loan recoveries of statutory capital	89.00%	89.00%	59.00%
Total shareholders' equity of MBIA Inc.	1,700,000,000	1,700,000,000	2,832,000,000					1,700,000,000	2,832,000,000	2,590,000,000	994,000,000
Liquid assets						534,000,000	1,200,000,000	226,000,000				703,000,000																						160,000,000
Claim payments																																			835,000,000	2,500,000,000
Commuted gross insured exposure													32,400,000,000
Insured par exposure														6,100,000,000	5,600,000,000	29,100,000,000	29,800,000,000																				3,400,000,000			19,300,000,000
National Secured Loan	1,100,000,000	1,100,000,000
MBIA Corp secured loan																						168,000,000
National Secured Loan, interest rate		7.00%
National asset swap																		2,000,000,000	1,300,000,000
National asset swap, percentage																							0.34%	0.35%	1.70%
Secured Loan balance																											300,000,000	300,000,000	675,000,000	675,000,000			2,000,000,000
MBIA Secured Loan, average interest rate																										2.43%
Conduit Repurchase Agreement																		1,000,000,000									80,000,000
Conduit Repurchase Agreement, percentage																							2.41%
Contingency reserve release to surplus	582,000,000	900,000,000
Approved, secured loan maximum outstanding amount	450,000,000	450,000,000
Payment on tax agreement related to estimated taxes		144,000,000	114,000,000
Fair value of collateral pledged																				1,400,000,000	1,500,000,000
Cash payments for second lien RMBS securitizations and CDS contracts																															6,200,000,000							730,000,000			10,700,000,000
Invested assets at amortized cost to liabilities at amortized cost issued to third-parties and affiliates at amortized cost	591,000,000	591,000,000
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate		35.00%	35.00%	35.00%
Cash and available-for-sale investments						$ 1,500,000,000						$ 771,000,000
Federal statutory rate		35.00%	35.00%	35.00%