Investments and Cash - Summarized Financial Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Schedule of Equity Method Investments [Line Items]
Investments	$ 9,115	$ 8,365
Assets of consolidated investment vehicles (includes $331 and $5,363, at fair value)	366	5,493
Other assets (includes $123 and $148, at fair value)	700	597
Total assets	12,539	16,843
Liabilities of consolidated investment vehicles (includes $0 and $4,431, at fair value)	4	4,625
Other liabilities	435	457
Total liabilities	6,774	11,551
Total shareholders’ equity attributable to AGL	5,713	5,064
Nonredeemable noncontrolling interests (Note 8)	52	228
Total equity	5,765	5,292	$ 6,478	$ 6,684
Net realized investment gains (losses)	(14)	(56)	15
Other income (loss)	61	17	21
Total revenues	1,373	723	848
Total expenses	733	536	465
Net income (loss)	761	137	419
Equity in earnings (losses) of investees	28	(39)	94
Nonconsolidated Investees, Other
Schedule of Equity Method Investments [Line Items]
Equity in earnings (losses) of investees	127	(364)	484
Equity Method Investment
Schedule of Equity Method Investments [Line Items]
Investments	1,735	444
Assets of consolidated investment vehicles (includes $331 and $5,363, at fair value)	1,449	0
Other assets (includes $123 and $148, at fair value)	792	253
Total assets	3,976	697
Liabilities of consolidated investment vehicles (includes $0 and $4,431, at fair value)	1,342	0
Other liabilities	365	76
Total liabilities	1,707	76
Total shareholders’ equity attributable to AGL	2,234	621
Nonredeemable noncontrolling interests (Note 8)	35	0
Total equity	2,269	621
Fee income	57	15	29
Net realized investment gains (losses)	129	(365)	456
Income of consolidated funds and CLOs	37	0	0
Other income (loss)	39	35	63
Total revenues	262	(315)	548
Expenses of consolidated funds and CLOs	25	0	0
Other expenses	108	49	64
Total expenses	133	49	64
Net income (loss)	$ 129	$ (364)	$ 484