Consolidated Balance Sheets (USD $) In Millions, unless otherwise specified	Dec. 31, 2012		Dec. 31, 2011
Assets
Cash and cash equivalents	$ 990		$ 633
Deferred income taxes, net	1,200
Total assets	21,724		26,873
Liabilities:
Total liabilities	18,530		25,150
Commitments and contingencies (See Note 20)
Equity:
Preferred stock, par value $1 per share; authorized shares-10,000,000; issued and outstanding-none
Common stock, par value $1 per share; authorized shares-400,000,000; issued shares-277,405,039 and 274,896,162	277		275
Additional paid-in capital	3,076		3,072
Retained earnings	2,039		805
Accumulated other comprehensive income (loss), net of tax of $21 and $105	56		(176)
Treasury stock, at cost-81,733,530 and 81,752,966 shares	(2,275)		(2,276)
Total shareholders' equity of MBIA Inc.	3,173		1,700
Preferred stock of subsidiary and noncontrolling interest	21		23
Total equity	3,194		1,723
Total liabilities and equity	21,724		26,873
Non Variable Interest Entities [Member]
Assets
Fixed-maturity securities held as available-for-sale, at fair value	4,485		6,177
Fixed-maturity securities at fair value	244		295
Investments pledged as collateral, at fair value (amortized cost $489 and $642)	443		543
Short-term investments held as available-for-sale, at fair value (amortized cost $662 and $1,577)	669		1,571
Other investments (includes investments at fair value of $12 and $96)	21		107
Total investments	5,862		8,693
Cash and cash equivalents	814		473
Premiums receivable	1,228		1,360
Deferred acquisition costs	302		351
Insurance loss recoverable	3,648		3,046
Property and equipment, at cost (less accumulated depreciation of $146 and $139)	69		69
Deferred income taxes, net	1,199		1,745
Other assets	268		243
Liabilities:
Unearned Premium Revenue	2,938		3,515
Loss and loss adjustment expense reserves	853		836
Investment agreements	944		1,578
Medium-term notes (includes financial instruments carried at fair value of $165 and $165)	1,598		1,656
Securities sold under agreements to repurchase			287
Long-term debt	1,662		1,840
Derivative liabilities	2,934		5,164
Other liabilities	315		391
Variable Interest Entity [Member]
Assets
Cash	176		160
Investments held-to-maturity, at amortized cost (fair value $2,674 and $3,489)	2,829		3,843
Fixed-maturity securities held as available-for-sale, at fair value	625		432
Fixed-maturity securities at fair value	1,735		2,884
Loans receivable at fair value	1,881		2,046
Loan repurchase commitments	1,086		1,077
Derivative assets			450
Other assets	2		1
Total assets	8,300		10,900
Liabilities:
Variable interest entity notes (includes financial instruments carried at fair value of $3,659 and $4,754)	7,124	[1]	8,697
Long-term debt			360
Derivative liabilities	162		825
Other liabilities			1
Total liabilities	$ 7,300		$ 9,900

[1] Includes $3.7 billion of VIE notes accounted for at fair value as of December 31, 2012.