Investments and Cash - Summarized Financial Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Schedule of Equity Method Investments [Line Items]
Investments	$ 8,663	$ 9,115
Assets of consolidated investment vehicles (includes $99 and $331, at fair value)	101	366
Other assets (includes $131 and $123, at fair value)	746	706
Total assets	11,901	12,539
Other liabilities (includes $34000000 and $53000000 at fair value)	498	492
Total liabilities	6,348	6,774
Total shareholders’ equity attributable to AGL	5,495	5,713
Nonredeemable noncontrolling interests (Note 8)	58	52
Total equity	5,553	5,765	$ 5,292	$ 6,478
Net realized investment gains (losses)	9	(14)	(56)
Other income (loss)	23	61	17
Total revenues	872	1,373	723
Total expenses	446	733	536
Net income (loss)	392	761	137
Equity in earnings (losses) of investees	62	28	(39)
Nonconsolidated Investees, Other
Schedule of Equity Method Investments [Line Items]
Equity in earnings (losses) of investees	400	127	(364)
Equity Method Investment
Schedule of Equity Method Investments [Line Items]
Investments	2,324	1,735
Assets of consolidated investment vehicles (includes $99 and $331, at fair value)	1,611	1,449
Other assets (includes $131 and $123, at fair value)	754	792
Total assets	4,689	3,976
Liabilities of consolidated funds and CLOs	1,494	1,342
Other liabilities (includes $34000000 and $53000000 at fair value)	526	365
Total liabilities	2,020	1,707
Total shareholders’ equity attributable to AGL	2,629	2,234
Nonredeemable noncontrolling interests (Note 8)	40	35
Total equity	2,669	2,269
Fee income	196	57	15
Net realized investment gains (losses)	400	129	(365)
Income of consolidated funds and CLOs	138	37	0
Other income (loss)	48	39	35
Total revenues	782	262	(315)
Expenses of consolidated funds and CLOs	93	25	0
Other expenses	279	108	49
Total expenses	372	133	49
Net income (loss)	$ 410	$ 129	$ (364)