Consolidated Balance Sheets (USD $) In Millions, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Assets
Cash and cash equivalents	$ 733	$ 1,258
Deferred income taxes, net	917
Investments held-to-maturity, at amortized cost (fair value $2,695 and $2,651)	2,793	2,801
Total assets	16,087	16,953
Liabilities:
Total liabilities	12,462	13,654
Commitments and contingencies (See Note 13)
Equity:
Preferred stock, par value $1 per share; authorized shares--10,000,000; issued and outstanding--none	0	0
Common stock, par value $1 per share; authorized shares--400,000,000; issued shares--281,291,579 and 277,812,430	281	278
Additional paid-in capital	3,115	3,115
Retained earnings	2,545	2,289
Accumulated other comprehensive income (loss), net of tax of $16 and $54	(13)	(86)
Treasury stock, at cost--86,086,648 and 85,562,546 shares	(2,324)	(2,318)
Total shareholders' equity of MBIA Inc.	3,604	3,278
Preferred stock of subsidiary and noncontrolling interest	21	21
Total equity	3,625	3,299
Total liabilities and equity	16,087	16,953
Non Variable Interest Entity [Member]
Assets
Fixed-maturity securities held as available-for-sale, at fair value (amortized cost $5,173 and $5,064) Investments held as available-for-sale, at fair value (amortized cost $35 and $136)	5,200	4,987
Investments carried at fair value	212	204
Investments pledged as collateral, at fair value (amortized cost $329 and $483)	278	424
Short-term investments held as available-for-sale, at fair value (amortized cost $1,318 and $1,203)	1,319	1,204
Other investments (includes investments at fair value of $12 and $11)	16	16
Total investments	7,025	6,835
Cash and cash equivalents	679	1,161
Premiums receivable	1,009	1,051
Deferred acquisition costs	250	260
Insurance loss recoverable	671	694
Assets held for sale	29	29
Deferred income taxes, net	917	1,109
Other assets	200	222
Liabilities:
Unearned premium revenue	2,337	2,441
Loss and loss adjustment expense reserves	602	641
Investment agreements	689	700
Medium-term notes (includes financial instruments carried at fair value of $215 and $203)	1,418	1,427
Long-term debt	1,731	1,702
Derivative liabilities	381	1,152
Other liabilities	287	294
Variable Interest Entity Primary Beneficiary [Member]
Assets
Fixed-maturity securities held as available-for-sale, at fair value (amortized cost $5,173 and $5,064) Investments held as available-for-sale, at fair value (amortized cost $35 and $136)	35	136
Investments carried at fair value	504	587
Cash	54	97
Investments held-to-maturity, at amortized cost (fair value $2,695 and $2,651)	2,793	2,801
Loans receivable at fair value	1,557	1,612
Loan repurchase commitments	364	359
Liabilities:
Derivative liabilities	5	11
Variable interest entity notes (includes financial instruments carried at fair value of $2,194 and $2,356)	$ 5,012	$ 5,286