Insurance - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Insurance [Line Items]
Carrying value of cash and securities owned by U.S.-based insurance subsidiaries on deposit	$ 1,220
Workers' compensation insurance discount rate	4.50%	3.50%
Amortization of deferred policy acquisition costs	$ 720	$ 641	$ 580
Dividends on common stock	687	1,220	$ 2,380
Dividends payments without violating the most restrictive debt covenants, minimum	1,500
Maximum
Insurance [Line Items]
Maximum amount of dividends available to be paid by insurance subsidiaries to AFG without prior approval of regulatory authorities	$ 944
Catastrophe Bonds
Insurance [Line Items]
Catastrophe reinsurance coverage, excess retention percentage	94.00%
Reinsurance, excess retention, amount reinsured, per event	$ 323
Reinsurance, amount retained, per event	127
Catastrophe reinsurance coverage, annual cost	16
Workers' Compensation Insurance
Insurance [Line Items]
Impact of discount on workers' compensation policies	$ 9
Impact of discount on workers' compensation policies, prior year amount		$ 9