Schedule II - Condensed Financial Information of Registrant (Parent Company Only) Schedule II - Condensed Financial Information of Registrant - Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information [Line Items]
Operating Loss Carryforwards	$ 1,690,842
AFG [Member]
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information [Line Items]
Operating Loss Carryforwards	$ 1,690,842
Ambac Assurance [Member]
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information [Line Items]
Operating Loss Carryforwards		$ 1,952,621
Ambac Assurance [Member] | Minimum [Member]
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information [Line Items]
Operating Loss Carryforwards, Expiration Date	Dec. 31, 2030
Ambac Assurance [Member] | Maximum [Member]
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information [Line Items]
Operating Loss Carryforwards, Expiration Date	Dec. 31, 2042
Interest Expense | U. S. Federal Net Operating Tax
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information [Line Items]
Operating Loss Carryforwards		$ 110,494