Insurance Contracts - Summary of Information Related to Policies Currently Included in Ambac's Loss Reserves or Subrogation Recoverable (Phantom) (Details) - USD ($) $ in Millions	Jun. 30, 2024	Dec. 31, 2023	Jun. 30, 2023
Schedule of Insured Financial Obligations with Credit Deterioration [Line Items]
Subrogation recoverable	$ (128)	$ (137)
Liability for Claims	$ 890	$ 893
Ceded Loss And Loss Expenses Paid Not Yet Recovered			$ 5

Ceded Loss And Loss Expenses Paid Not Yet Recovered

No definition available.

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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- Definition

The amount needed to reflect the estimated ultimate cost of settling claims relating to insured events that have occurred on or before the balance sheet date, whether or not reported to the insurer at that date.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 944
-SubTopic 40
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (cc)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480081/944-40-50-3

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 944
-SubTopic 40
-Section 50
-Paragraph 3
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480081/944-40-50-3

+ Details

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Period Type:	instant

- Definition

The estimated amount as of the balance sheet date to be received by an insurer from the sale of property (usually damaged) on which the insurer has paid a total claim to the insured and has obtained title to the property and the right of an insurer to pursue any course of recovery of damages, in its name or in the name of the policyholder, against a third party who is liable for costs relating to an insured event that have been paid by the insurer. Estimated salvage and subrogation is generally deducted from the liability for unpaid claims.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 944
-SubTopic 40
-Section 30
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479224/944-40-30-2

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 944
-SubTopic 40
-Section 30
-Paragraph 3
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479224/944-40-30-3

+ Details

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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.

+ Details

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