Condensed Financial Information of Parent Company - Condensed Statement of Cash Flows (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Operating Activities:
Net earnings attributable to shareholders	$ 898	$ 1,995	$ 732
Adjustments:
Net cash provided by operating activities	1,153	1,714	2,183
Investing Activities:
Payments to acquire subsidiaries	(10)	(123)	(3)
Net cash used in investing activities	(1,051)	(436)	(1,564)
Financing Activities:
Additional long-term borrowings	0	0	634
Reductions of long-term debt	(477)	0	(150)
Issuances of Common Stock	16	66	22
Repurchases of Common Stock	(11)	(319)	(313)
Cash dividends paid on Common Stock	(1,213)	(2,374)	(334)
Net cash used in financing activities	(1,361)	(1,957)	(123)
Cash and cash equivalents, period increase (decrease)	(1,259)	(679)	496
Cash and cash equivalents at beginning of year	2,131
Cash and cash equivalents at end of year	872	2,131
AFG
Operating Activities:
Net earnings attributable to shareholders	898	1,995	732
Adjustments:
Equity in net earnings of subsidiaries	(1,030)	(2,144)	(780)
Dividends from subsidiaries	539	830	543
Other operating activities, net	(80)	152	(12)
Net cash provided by operating activities	327	833	483
Investing Activities:
Capital contributions to subsidiaries	(26)	(107)	(297)
Returns of capital from subsidiaries	29	3	0
Investments, property and equipment	(223)	(1,478)	(2)
Payments to acquire subsidiaries	0	(120)	0
Proceeds from maturities and redemptions of investments	556	277	2
Sales of investments, property and equipment	656	11	0
Proceeds from sales of businesses	0	3,581	3
Net cash used in investing activities	992	2,167	(294)
Financing Activities:
Additional long-term borrowings	0	0	634
Reductions of long-term debt	(477)	0	(150)
Issuances of Common Stock	18	67	23
Repurchases of Common Stock	(11)	(319)	(313)
Cash dividends paid on Common Stock	(1,213)	(2,374)	(334)
Net cash used in financing activities	(1,683)	(2,626)	(140)
Cash and cash equivalents, period increase (decrease)	(364)	374	49
Cash and cash equivalents at beginning of year	589	215	166
Cash and cash equivalents at end of year	$ 225	$ 589	$ 215