Insurance [Line Items]

No definition available.

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- Definition

The valuation allowance as of the balance sheet date to reduce the gross amount of receivables to estimated net realizable value, which would be presented in parentheses on the face of the balance sheet.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=118936363&loc=d3e5074-111524

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- Definition

Amount after tax of increase (decrease) to equity or (increase) decrease to net assets, resulting from the cumulative effect adjustment of a new accounting principle applied in the period of adoption.

+ References

No definition available.

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- Definition

This element represents the amount of premium revenue on financial guarantee insurance contracts recognized during the period that was accelerated for revenue recognition purposes.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 605
-Section 50
-Paragraph 4
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=6933581&loc=SL5749298-161291

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- Definition

Amount of the premium receivable for financial guarantee insurance contracts reported in the statement of financial position. This element primarily would consist of those financial guarantee insurance contracts which premiums are to be collected over the contract period, but may, on occasion, include premiums which are to be collected in full at inception, but which straddle a financial reporting period.

+ References

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- Definition

Amount of cash inflow from premiums received for premium receivable on financial guarantee insurance contracts.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
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- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

+ References

No definition available.

+ Details

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- Definition

Amount of accretion of the discount for premiums receivable on financial guarantee insurance contracts.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
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-Paragraph 3
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- Definition

Amount of increase (decrease) in the premium receivable on financial guarantee insurance contracts from changes in the period of the contract.

+ References

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-Publisher FASB
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- Definition

Amount of increase (decrease) in the premiums receivable on financial guarantee insurance contracts from adjustments classified as other.

+ References

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- Definition

Amount of financing receivable 90 days or more past due and still accruing.

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- Definition

Amount of financing receivable past due.

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- Definition

Amount of expense (reversal of expense) for expected credit loss on premium receivable.

+ References

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- Definition

The carrying value as of the balance sheet date of the estimated valuation allowance to reduce gross premiums receivable to net realizable value.

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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-Name Accounting Standards Codification
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- Definition

Amount of increase (decrease) in allowance for credit loss on premium receivable.

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- Definition

Amount of recoveries of premiums receivable that were previously written off as bad debts.

+ References

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- Definition

Amount of writeoff of premium receivable, charged against allowance for credit loss.

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- Definition

Gross amount, as of the balance sheet date, due the entity from (a) agents and insureds, (b) uncollected premiums and (c) others, before deducting the allowance for doubtful accounts.

+ References

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-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03.5)
-URI http://asc.fasb.org/extlink&oid=119400593&loc=d3e572229-122910

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Financial Guarantee Insurance Contracts - Summary of Gross Premium Receivable Roll-Forward (Direct and Assumed Contracts) (Details) $ in Thousands, € in Millions, £ in Millions	3 Months Ended
	Mar. 31, 2021 USD ($)	Mar. 31, 2021 GBP (£)	Mar. 31, 2021 EUR (€)	Mar. 31, 2020 USD ($)	Mar. 31, 2020 GBP (£)	Mar. 31, 2020 EUR (€)	Dec. 31, 2020 USD ($)	Jan. 01, 2020 USD ($)	Dec. 31, 2019 USD ($)
Insurance [Line Items]
Allowance for Doubtful Accounts, Premiums and Other Receivables	$ 13,000			$ 14,000			$ 17,000		$ 9,000
Financial Guarantee Insurance Contracts, Accelerated Premium Revenue, Amount	0			187
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Beginning premium receivable	370,000			416,000
Premium receipts	12,000			12,000
Adjustments for changes in expected and contractual cash flows	(8,000)			10,000
Accretion of premium receivable discount	2,000			2,000
Uncollectable premiums	4,000			(2,000)
Other adjustments (including foreign exchange)	0			(8,000)
Ending premium receivable	356,000			403,000
Premium Receivable, Allowance for Credit Loss	13,000						17,000
Premium Receivable, Credit Loss Expense (Reversal)	(4,000)			5,000
Premium Receivable, Allowance for Credit Loss, Writeoff	0			0
Premium Receivable, Allowance for Credit Loss, Recovery	0			0
Financing Receivable, Past Due	69						74
Financing Receivable, 90 Days or More Past Due, Still Accruing	63						98
Premiums Receivable, Gross	369,000						387,000
Public Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	167,000						185,000
Structured Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	55,000						59,000
International Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	148,000						144,000
I/SL [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	302,000						302,000
I/SL [Member] \| Public Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	154,000						157,000
I/SL [Member] \| Structured Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	25,000						27,000
I/SL [Member] \| International Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	123,000						118,000
IA [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	25,000						40,000
IA [Member] \| Public Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	13,000						27,000
IA [Member] \| Structured Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	0						0
IA [Member] \| International Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	12,000						13,000
II [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	3,000						3,000
II [Member] \| Public Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	0						0
II [Member] \| Structured Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	3,000						3,000
II [Member] \| International Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	0						0
III [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	25,000						27,000
III [Member] \| Public Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	0						0
III [Member] \| Structured Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	13,000						14,000
III [Member] \| International Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	12,000						13,000
IV [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	14,000						15,000
IV [Member] \| Public Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	0						0
IV [Member] \| Structured Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	14,000						15,000
IV [Member] \| International Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	0						0
United Kingdom, Pounds
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Ending premium receivable	122,000	£ 89		128,000	£ 103
Euro Member Countries, Euro
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Ending premium receivable	21,000		€ 18	24,000		€ 22
Accounting Standards Update 2016-13 [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Cumulative Effect of New Accounting Principle in Period of Adoption				$ (4,000)
Premiums Receivable [Member] \| Accounting Standards Update 2016-13 [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Cumulative Effect of New Accounting Principle in Period of Adoption								$ (3,000)
Other Public Finance Sectors [Member] \| Public Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	2,000						17,000
Other Public Finance Sectors [Member] \| I/SL [Member] \| Public Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	2,000						2,000
Other Public Finance Sectors [Member] \| IA [Member] \| Public Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	0						15,000
Other Public Finance Sectors [Member] \| II [Member] \| Public Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	0						0
Other Public Finance Sectors [Member] \| III [Member] \| Public Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	0						0
Other Public Finance Sectors [Member] \| IV [Member] \| Public Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	0						0
Other International [Member] \| International Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	6,000						5,000
Other International [Member] \| I/SL [Member] \| International Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	6,000						5,000
Other International [Member] \| IA [Member] \| International Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	0						0
Other International [Member] \| II [Member] \| International Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	0						0
Other International [Member] \| III [Member] \| International Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	0						0
Other International [Member] \| IV [Member] \| International Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	0						0
Mortgage Backed And Home Equity [Member] \| Structured Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	20,000						22,000
Mortgage Backed And Home Equity [Member] \| I/SL [Member] \| Structured Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	2,000						3,000
Mortgage Backed And Home Equity [Member] \| IA [Member] \| Structured Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	0						0
Mortgage Backed And Home Equity [Member] \| II [Member] \| Structured Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	1,000						1,000
Mortgage Backed And Home Equity [Member] \| III [Member] \| Structured Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	3,000						3,000
Mortgage Backed And Home Equity [Member] \| IV [Member] \| Structured Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	14,000						15,000
Structured Insurance [Domain] \| Structured Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	14,000						14,000
Structured Insurance [Domain] \| I/SL [Member] \| Structured Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	14,000						14,000
Structured Insurance [Domain] \| IA [Member] \| Structured Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	0						0
Structured Insurance [Domain] \| II [Member] \| Structured Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	0						0
Structured Insurance [Domain] \| III [Member] \| Structured Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	0						0
Structured Insurance [Domain] \| IV [Member] \| Structured Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	0						0
Student Loans [Member] \| Structured Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	14,000						16,000
Student Loans [Member] \| I/SL [Member] \| Structured Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	2,000						3,000
Student Loans [Member] \| IA [Member] \| Structured Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	0						0
Student Loans [Member] \| II [Member] \| Structured Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	2,000						2,000
Student Loans [Member] \| III [Member] \| Structured Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	10,000						11,000
Student Loans [Member] \| IV [Member] \| Structured Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	0						0
Other Structured Finance [Member] \| Structured Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	7,000						7,000
Other Structured Finance [Member] \| I/SL [Member] \| Structured Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	7,000						7,000
Other Structured Finance [Member] \| IA [Member] \| Structured Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	0						0
Other Structured Finance [Member] \| II [Member] \| Structured Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	0						0
Other Structured Finance [Member] \| III [Member] \| Structured Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	0						0
Other Structured Finance [Member] \| IV [Member] \| Structured Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	0						0
Sovereign And Sub Sovereign [Member] \| International Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	111,000						108,000
Sovereign And Sub Sovereign [Member] \| I/SL [Member] \| International Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	86,000						82,000
Sovereign And Sub Sovereign [Member] \| IA [Member] \| International Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	12,000						13,000
Sovereign And Sub Sovereign [Member] \| II [Member] \| International Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	0						0
Sovereign And Sub Sovereign [Member] \| III [Member] \| International Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	12,000						13,000
Sovereign And Sub Sovereign [Member] \| IV [Member] \| International Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	0						0
Investor Owned And Public Utilities [Member] \| International Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	30,000						31,000
Investor Owned And Public Utilities [Member] \| I/SL [Member] \| International Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	30,000						31,000
Investor Owned And Public Utilities [Member] \| IA [Member] \| International Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	0						0
Investor Owned And Public Utilities [Member] \| II [Member] \| International Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	0						0
Investor Owned And Public Utilities [Member] \| III [Member] \| International Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	0						0
Investor Owned And Public Utilities [Member] \| IV [Member] \| International Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	0						0
Housing Revenue [Member] \| Public Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	165,000						168,000
Housing Revenue [Member] \| I/SL [Member] \| Public Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	152,000						155,000
Housing Revenue [Member] \| IA [Member] \| Public Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	13,000						13,000
Housing Revenue [Member] \| II [Member] \| Public Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	0						0
Housing Revenue [Member] \| III [Member] \| Public Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	0						0
Housing Revenue [Member] \| IV [Member] \| Public Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	$ 0						$ 0