Insurance - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Insurance [Line Items]
Carrying value of cash and securities owned by U.S.-based insurance subsidiaries on deposit	$ 1,120
Workers' compensation insurance discount rate	3.50%	3.50%
Workers' compensation insurance discount, which has reduced the liability for unpaid losses and loss adjustment expenses	$ 9	$ 8
Pretax COVID-19 related losses		16	$ 115
Amortization of deferred policy acquisition costs	641	580	615
Dividends on common stock	1,220	2,380	336
Dividends payments without violating the most restrictive debt covenants, minimum	1,000
Maximum
Insurance [Line Items]
Maximum amount of dividends available to be paid by insurance subsidiaries to AFG without prior approval of regulatory authorities	$ 887
Catastrophe Bonds
Insurance [Line Items]
Catastrophe reinsurance coverage, excess retention percentage	94.00%
Reinsurance, excess retention, amount reinsured, per event	$ 325
Reinsurance, amount retained, per event	125
Catastrophe reinsurance coverage, annual cost	16
Neon exited lines charge
Insurance [Line Items]
Prior year claims and claims adjustment expense	0	0	19
Other
Insurance [Line Items]
Prior year claims and claims adjustment expense	(285)	(279)	(193)
Other | COVID-19
Insurance [Line Items]
Prior year claims and claims adjustment expense	$ (19)	$ (19)
Property and casualty insurance | Other lines
Insurance [Line Items]
Special A&E charges			47
Neon Capital Limited | Property and casualty insurance | Other lines
Insurance [Line Items]
Pretax COVID-19 related losses			$ 20