Insurance - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Insurance [Line Items]
Carrying value of cash and securities owned by U.S.-based insurance subsidiaries on deposit	$ 1,150
Workers' compensation insurance discount rate	4.50%	4.50%
Amortization of deferred policy acquisition costs	$ 766	$ 720	$ 641
Dividends on common stock	791	687	$ 1,220
Dividends payments without violating the most restrictive debt covenants, minimum	1,620
Maximum
Insurance [Line Items]
Maximum amount of dividends available to be paid by insurance subsidiaries to AFG without prior approval of regulatory authorities	1,000
Workers' Compensation Insurance
Insurance [Line Items]
Impact of discount on workers' compensation policies	$ 8
Impact of discount on workers' compensation policies, prior year amount		$ 9