Insurance in Force (Narrative) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Guarantor Obligations [Line Items]
Transactions guaranteed by MBIA on behalf of affiliated companies	$ 2,200	$ 2,600
Derivative liabilities	88	246
Amount available under these letters of credit and trust arrangements	33
Aggregate amount of insurance in force ceded to reinsurers	9,500	11,100
Aggregate amount of insured par outstanding ceded to reinsurers	5,294	6,100
Recoveries received on claims for financial guarantee policies under reinsurance contracts	0	5	$ 4
Ceding commissions from reinsurance	1	$ 2	$ 2
Guarantees Of Derivative Contracts [Member]
Guarantor Obligations [Line Items]
Guarantee Obligations Maximum Exposure	$ 3,800
Minimum [Member]
Guarantor Obligations [Line Items]
Insurance in force, expected maturity range, years	1 year
Guarantees of derivative contracts, maturity range, minimum (Years)	1 year
Minimum [Member] | Investment Agreement Contracts and MTNs [Member]
Guarantor Obligations [Line Items]
Future guarantee payments, maturity range, (years)	1 year
Maximum [Member]
Guarantor Obligations [Line Items]
Insurance in force, expected maturity range, years	42 years
Guarantees of derivative contracts, maturity range, maximum (Years)	67 years
Maximum [Member] | Investment Agreement Contracts and MTNs [Member]
Guarantor Obligations [Line Items]
Future guarantee payments, maturity range, (years)	24 years