Schedule II - Condensed Financial Information of Registrant (Parent Company Only) Schedule II - Condensed Financial Information of Registrant - Income Taxes (Details) $ in Millions	12 Months Ended
	Dec. 31, 2023 USD ($)
Operating Loss Carryforwards	$ 3,400
AFG [Member]
Operating Loss Carryforwards	1,640
Ambac Assurance [Member]
Operating Loss Carryforwards	$ 1,760
Ambac Assurance [Member] | Minimum [Member]
Operating Loss Carryforwards, Expiration Date	Dec. 31, 2030
Ambac Assurance [Member] | Maximum [Member]
Operating Loss Carryforwards, Expiration Date	Dec. 31, 2042
Interest Expense | U. S. Federal Net Operating Tax [Member]
Operating Loss Carryforwards	$ 274