Condensed Financial Information of Parent Company - Condensed Statement of Cash Flows (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Operating Activities:
Net earnings	$ 887	$ 852	$ 898
Adjustments:
Net cash provided by operating activities	1,152	1,970	1,153
Investing Activities:
Payments to acquire subsidiaries	(9)	(234)	(10)
Net cash provided by (used in) investing activities	95	414	(1,051)
Financing Activities:
Reductions of long-term debt	0	(21)	(477)
Issuances of Common Stock	17	15	16
Repurchases of Common Stock	0	(213)	(11)
Cash dividends paid on Common Stock	(788)	(684)	(1,213)
Net cash used in financing activities	(1,066)	(2,031)	(1,361)
Cash and cash equivalents, period increase (decrease)	181	353	(1,259)
Cash and cash equivalents at beginning of year	1,225
Cash and cash equivalents at end of year	1,406	1,225
AFG
Operating Activities:
Net earnings	887	852	898
Adjustments:
Equity in net earnings of subsidiaries	(1,030)	(967)	(1,030)
Dividends from subsidiaries	812	896	539
Other operating activities, net	43	(62)	(80)
Net cash provided by operating activities	712	719	327
Investing Activities:
Capital contributions to subsidiaries	(36)	(180)	(26)
Returns of capital from subsidiaries	30	7	29
Purchases of investments, property and equipment	(55)	(35)	(223)
Proceeds from maturities and redemptions of investments	129	255	556
Sales of investments, property and equipment	4	178	656
Net cash provided by (used in) investing activities	72	225	992
Financing Activities:
Reductions of long-term debt	0	(21)	(477)
Issuances of Common Stock	19	17	18
Repurchases of Common Stock	0	(213)	(11)
Cash dividends paid on Common Stock	(788)	(684)	(1,213)
Net cash used in financing activities	(769)	(901)	(1,683)
Cash and cash equivalents, period increase (decrease)	15	43	(364)
Cash and cash equivalents at beginning of year	268	225	589
Cash and cash equivalents at end of year	$ 283	$ 268	$ 225