Debt instrument, call date for first fifth anniversary.

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- Definition

Debt instrument maturity year.

+ References

No definition available.

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- Definition

long-term debt principal amount previously purchased.

+ References

No definition available.

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- Definition

Amount of amortization expense attributable to debt issuance costs.

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- Definition

Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

+ References

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- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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- Definition

Date when the debt instrument is scheduled to be fully repaid, in CCYY-MM-DD format.

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- Definition

Percentage of principal amount of debt redeemed.

+ References

No definition available.

+ Details

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- Definition

Weighted average interest rate of debt outstanding.

+ References

No definition available.

+ Details

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- Definition

Difference between the fair value of payments made and the carrying amount of debt which is extinguished prior to maturity.

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- Definition

The cash outflow paid to third parties in connection with debt origination, which will be amortized over the remaining maturity period of the associated long-term debt.

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- Definition

The cash inflow from a borrowing where a lender is placed in a lien position behind debt having a higher priority of repayment (senior) in liquidation of the entity's assets or underlying collateral.

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Debt (Narrative) (Detail) - USD ($) $ in Millions	12 Months Ended
Debt (Narrative) (Detail) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Net gains (losses) on extinguishment of debt		$ (1)	$ 3
long-term debt principal amount issued	$ 2,229	2,228
MBIA Inc. Senior Notes [Member]
Debt Instrument [Line Items]
Debt instrument interest rate	5.70%
Long-term debt, maturity year	2034
MBIA Corp Surplus Notes [Member]
Debt Instrument [Line Items]
Callable date for fifth anniversary of initial callable date	Jan. 15, 2023
Mbia Inc. Debentures [Member]
Debt Instrument [Line Items]
Debt instrument interest rate	7.00%
Long-term debt, maturity year	2025
6.400% Senior Notes due 2022 [Member]
Debt Instrument [Line Items]
Percentage of debt redemption	100.00%
Debt instrument interest rate	6.40%
Long-term debt, maturity year	2022
long-term debt principal amount issued	$ 0	115
Long-term debt principal amount previously purchased	$ 115	$ 150
Medium-term notes [Member]
Debt Instrument [Line Items]
Weighted average interest rate	2.97%	3.07%
Investment Agreement Obligations [Member]
Debt Instrument [Line Items]
Weighted average interest rate	5.86%	5.86%
Refinanced Facility [Member]
Debt Instrument [Line Items]
Proceeds from issuance of senior notes		$ 54
Debt issuance cost paid		6
Refinanced Facility [Member] \| Expenses Of Consolidated Variable Interest Entities [Member]
Debt Instrument [Line Items]
Debt issuance cost expensed		3
MBIA Corp Financing Facility [Member]
Debt Instrument [Line Items]
Debt instrument interest rate	12.00%
Long-term debt, maturity date	Jan. 20, 2022
MBIA Corp Financing Facility [Member] \| Initial [Member]
Debt Instrument [Line Items]
long-term debt principal amount issued		278
MBIA Corp Financing Facility [Member] \| Outstanding [Member]
Debt Instrument [Line Items]
long-term debt principal amount issued	$ 273	$ 246
Mbia Inc [Member] \| MBIA Corp Surplus Notes [Member]
Debt Instrument [Line Items]
Long-term debt principal amount previously purchased	13
National [Member] \| MBIA Inc. Senior Notes [Member]
Debt Instrument [Line Items]
Long-term debt principal amount previously purchased	308
National [Member] \| Mbia Inc. Debentures [Member]
Debt Instrument [Line Items]
Long-term debt principal amount previously purchased	10
Variable Interest Entity [Member]
Debt Instrument [Line Items]
Weighted average interest rate		5.57%
Variable Interest Entity Primary Beneficiary [Member]
Debt Instrument [Line Items]
long-term debt principal amount issued	1,400	$ 2,300
MBIA Insured Variable Interest Entity Primary Beneficiary [Member]
Debt Instrument [Line Items]
long-term debt principal amount issued	$ 722	$ 1,600
Maximum [Member] \| Medium-term notes [Member]
Debt Instrument [Line Items]
Debt instrument interest rate	6.00%	6.00%
Maximum [Member] \| Investment Agreement Obligations [Member]
Debt Instrument [Line Items]
Debt instrument interest rate	6.88%	6.88%
Maximum [Member] \| Variable Interest Entity [Member]
Debt Instrument [Line Items]
Debt instrument interest rate		12.00%
Minimum [Member] \| Medium-term notes [Member]
Debt Instrument [Line Items]
Debt instrument interest rate	0.00%	0.00%
Minimum [Member] \| Investment Agreement Obligations [Member]
Debt Instrument [Line Items]
Debt instrument interest rate	4.78%	4.78%
Minimum [Member] \| Variable Interest Entity [Member]
Debt Instrument [Line Items]
Debt instrument interest rate		3.71%