Debt (Narrative) (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended						12 Months Ended							0 Months Ended	12 Months Ended			0 Months Ended	12 Months Ended		0 Months Ended				12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2013 MBIA Inc Senior Notes [Member]	Dec. 31, 2012 MBIA Inc Senior Notes [Member]	Dec. 31, 2013 MBIA Corp Surplus Notes [Member]	Dec. 31, 2013 Medium Term Notes [Member]	Dec. 31, 2012 Medium Term Notes [Member]	Dec. 31, 2013 Medium Term Notes [Member] Conduits [Member]	Dec. 31, 2013 Medium Term Notes [Member] Global Funding Limited [Member]	Dec. 31, 2013 Investment Agreement Obligations [Member]	Dec. 31, 2012 Investment Agreement Obligations [Member]	May 06, 2013 Bank Of America [Member]	Dec. 31, 2013 Bank Of America [Member] MBIA Inc Senior Notes [Member]	Jan. 16, 2008 Mbia Corp [Member]	Jan. 16, 2008 Mbia Corp [Member] MBIA Corp Surplus Notes [Member]	May 06, 2013 Blue Ridge [Member]	Dec. 31, 2013 Blue Ridge [Member]	Nov. 30, 2013 Blue Ridge [Member]	May 06, 2013 Blue Ridge [Member] Libor Rate Loans [Member] Applicable Margin [Member]	May 06, 2013 Blue Ridge [Member] Base Rate Loans [Member] Applicable Margin [Member]	May 06, 2013 Blue Ridge [Member] Base Rate Loans [Member] Federal Funds Rate Margin [Member]	May 06, 2013 Blue Ridge [Member] Base Rate Loans [Member] Adjusted Libor Rate Margin [Member]	Dec. 31, 2012 Variable Interest Entity [Member] Medium Term Notes [Member]	Dec. 31, 2013 Variable Interest Entity [Member] Medium Term Notes [Member]
Debt Instrument [Line Items]
Aggregate principal amount in excess of stated amount	$ 10
Surplus notes outstanding	940	[1]	940	[1]												1,000
Long-term debt, interest rate																	14.00%
Interest rate terms							interest rate of 14% until January 15, 2013 and thereafter have an interest rate of three-month LIBOR plus 11.26%
Debt instrument, base reference rate	three-month LIBOR
Debt instrument, basis spread on variable rate	11.26%
Surplus notes purchased at par value							13
Surplus notes repurchased at outstanding par value							47
Surplus notes, weighted average price per unit	77.08
Annual interest rates, minimum								0.00%	0.00%			0.21%	0.28%												0.55%
Annual interest rates, maximum								8.93%	8.08%			7.38%	7.38%												1.71%
Weighted average interest rate								2.67%	2.89%			5.10%	5.04%												1.28%	1.02%
Accrued interest					8	9
Long-term debt	592		732
Amount received on litigation settlement														1,700	136
Par value redeemed										506	192
Weighted average percent of par										99.86%	91.35%
Line of credit maximum amount																		500
Line of credit amount outstanding																				70
Line of credit interest rate																					7.50%	6.50%	0.50%	1.00%
Line of credit commitment fee percentage																		2.00%
Line of credit interest and commitment fee																			7
Repayment of debt																			$ 72
Line of credit term																		3 years

[1] Callable on or after January 15, 2018 and every fifth anniversary thereafter at 100.00.