Condensed Financial Information of Parent Company - Condensed Statement of Cash Flows (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Operating Activities:
Net earnings	$ 852	$ 898	$ 1,995
Adjustments:
Net cash provided by operating activities	1,970	1,153	1,714
Investing Activities:
Payments to acquire subsidiaries	(234)	(10)	(123)
Net cash provided by (used in) investing activities	414	(1,051)	(436)
Financing Activities:
Reductions of long-term debt	(21)	(477)	0
Issuances of Common Stock	15	16	66
Repurchases of Common Stock	(213)	(11)	(319)
Cash dividends paid on Common Stock	(684)	(1,213)	(2,374)
Net cash used in financing activities	(2,031)	(1,361)	(1,957)
Cash and cash equivalents, period increase (decrease)	353	(1,259)	(679)
Cash and cash equivalents at beginning of year	872
Cash and cash equivalents at end of year	1,225	872
AFG
Operating Activities:
Net earnings	852	898	1,995
Adjustments:
Equity in net earnings of subsidiaries	(967)	(1,030)	(2,144)
Dividends from subsidiaries	896	539	830
Other operating activities, net	(62)	(80)	152
Net cash provided by operating activities	719	327	833
Investing Activities:
Capital contributions to subsidiaries	(180)	(26)	(107)
Returns of capital from subsidiaries	7	29	3
Investments, property and equipment	(35)	(223)	(1,478)
Payments to acquire subsidiaries	0	0	(120)
Proceeds from maturities and redemptions of investments	255	556	277
Sales of investments, property and equipment	178	656	11
Proceeds from sales of businesses	0	0	3,581
Net cash provided by (used in) investing activities	225	992	2,167
Financing Activities:
Reductions of long-term debt	(21)	(477)	0
Issuances of Common Stock	17	18	67
Repurchases of Common Stock	(213)	(11)	(319)
Cash dividends paid on Common Stock	(684)	(1,213)	(2,374)
Net cash used in financing activities	(901)	(1,683)	(2,626)
Cash and cash equivalents, period increase (decrease)	43	(364)	374
Cash and cash equivalents at beginning of year	225	589	215
Cash and cash equivalents at end of year	$ 268	$ 225	$ 589