Contracts Accounted for as Insurance - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2024	Dec. 31, 2023
Guarantor Obligations [Line Items]
Weighted average risk-free rates for U.S. dollar denominated financial guaranty insurance obligations	4.38%	4.15%
Gross	$ 416,463	$ 398,037
Gross Exposure	4,500
Ceded Business
Guarantor Obligations [Line Items]
Insured financial obligations insured contractual payments outstanding, amount represented	$ 497
Insured financial obligations insured contractual payments outstanding, percentage represented	0.10%
Gross Insured Specialty and Reinsurance Business
Guarantor Obligations [Line Items]
Insured financial obligations insured contractual payments outstanding, amount represented	$ 383
Minimum
Guarantor Obligations [Line Items]
Risk free discount rate	1.98%	1.90%
Maximum
Guarantor Obligations [Line Items]
Risk free discount rate	5.22%	5.40%
Premiums Receivable \| Foreign Currency Concentration Risk \| Premiums Receivable
Guarantor Obligations [Line Items]
Percentage of installment premiums denominated in currencies other than the U.S. dollar	69.00%	70.00%

Financial Guarantee Insurance Contracts, Claim Liability, Risk Free Discount Rate

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- Definition

Insured Financial Obligations Insured Contractual Payments Outstanding, Amount Represented

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No definition available.

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- Definition

Represents the amount of insured contractual payments (principal and interest) outstanding on the underlying insured obligations for direct financial guaranty contracts.

+ References

No definition available.

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Insured Financial Obligations Insured Contractual Payments Outstanding, Percentage Represented

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No definition available.

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- Definition

Specialty Insurance and Reinsurance, Gross Par

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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

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition

Weighted-average risk-free rate used to discount claim liability for financial guarantee insurance contract.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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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

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-Topic 460
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