Financial Guarantee Insurance - Summary of Percentage Ceded to Reinsurers and Reinsurance Recoverable and Rating Levels (Detail) $ in Millions	Dec. 31, 2021 USD ($)
Summary of Ceded Par and Net Unsecured Reinsurance Recoverable [Line Items]
Net unsecured reinsurance recoverable	$ 31
Reinsurance Recoverables, Gross	$ 55
Percentage of Ceded Reinsurance Recoverable Represented by Top Three	98.00%
QBE Insurance Corporation \| Property and Casualty, Commercial Insurance
Summary of Ceded Par and Net Unsecured Reinsurance Recoverable [Line Items]
Net unsecured reinsurance recoverable	$ 27
Reinsurance Recoverables, Gross	27
Assured Guaranty Re Ltd [Member] \| Financial Guarantee
Summary of Ceded Par and Net Unsecured Reinsurance Recoverable [Line Items]
Net unsecured reinsurance recoverable	0
Reinsurance Recoverables, Gross	18
Sompo Japan Nipponkoa Holdings, Inc [Member] \| Financial Guarantee
Summary of Ceded Par and Net Unsecured Reinsurance Recoverable [Line Items]
Net unsecured reinsurance recoverable	0
Reinsurance Recoverables, Gross	$ 9

Percentage of Ceded Reinsurance Recoverable Represented by Top Three

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- Definition

Summary of Ceded Par and Net Unsecured Reinsurance Recoverable [Line Items]

+ References

No definition available.

+ Details

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- Definition

Represents reinsurance recoverables on paid and unpaid losses and deferred ceded premiums, net of ceded premiums payables due to reinsurers, letters of credit, and collateral posted for the benefit of the cedant.

+ References

No definition available.

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- Definition

Amount before valuation allowance recoverable under reinsurance contracts. Examples include, but are not limited to, settled and unsettled claims, incurred but not reported losses, loss adjustment expense, premium paid, policy benefits and policy reserves.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 14
-URI http://asc.fasb.org/extlink&oid=124255953&loc=SL82919253-210447

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 7A
-URI http://asc.fasb.org/extlink&oid=123577603&loc=SL6953401-111524

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