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Contracts Accounted for as Insurance - Narrative (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Guarantor Obligations [Line Items]
Weighted average risk-free rates for U.S. dollar denominated financial guaranty insurance obligations	2.26%		1.02%
Net Economic Loss Development (Benefit)	$ (44)	$ 13
Public finance
Guarantor Obligations [Line Items]
Net Economic Loss Development (Benefit)	$ (50)	$ 3
Minimum
Guarantor Obligations [Line Items]
Weighted average risk-free rates for U.S. dollar denominated financial guaranty insurance obligations	0.00%		0.00%
Maximum
Guarantor Obligations [Line Items]
Weighted average risk-free rates for U.S. dollar denominated financial guaranty insurance obligations	2.61%		1.98%
Foreign Currency Concentration Risk | Premiums Receivable | Premiums Receivable
Guarantor Obligations [Line Items]
Percentage of installment premiums denominated in currencies other than the U.S. dollar	77.00%		78.00%

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- Definition

Guarantor Obligations, Net Expected Loss Development After Recoveries for Representations and Warranties

+ References

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- Definition

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

+ References

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- Definition

This element represents the weighted average risk free rate used to discount the claim liability related to financial guarantee insurance contracts.

+ References

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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.

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