Summary of Significant Accounting Policies - Adjusted Balance Sheet to Apply Adopted Guidance (Details) - USD ($) $ in Millions	Dec. 31, 2023		Dec. 31, 2022		Dec. 31, 2021	Jan. 01, 2021	Dec. 31, 2020
Assets:
Premiums and other receivables, net of allowance for credit losses and disputes of $139 in 2023 and $169 in 2022	$ 10,561		$ 13,243
Deferred income taxes	14,445		14,804			$ 12,963
Deferred policy acquisition costs	12,085		12,857			12,955
Market risk benefit assets, at fair value	912		796			338	$ 338
Other assets	13,089	[1]	12,384	[1]		13,520
Total assets	539,306		522,228			598,841
Liabilities:
Future policy benefits for life and accident and health insurance contracts	58,576		51,914			67,364
Policyholder contract deposits	161,979		155,984			148,223
Market risk benefit liabilities, at fair value	5,705		4,736			8,739	8,739
Other policyholder funds	3,356		3,463			3,796
Other liabilities(c)	25,958	[1]	26,757	[1]		27,520
Total liabilities	488,005		478,774			532,906
Additional paid-in capital	75,810		79,915
Retained earnings	37,516		34,893			16,437
Accumulated other comprehensive loss	(14,037)		(22,616)			11,314
Total AIG shareholders’ equity	45,351		40,970			65,098
Non-redeemable noncontrolling interests	5,950		2,484
Total equity	51,301		43,454		$ 69,034	65,935	67,199
Total liabilities and equity	539,306		522,228			598,841
Fortitude RE
Assets:
Reinsurance assets, net of allowance for credit losses and disputes	30,612		30,751			42,244	36,801
Excluding Fortitude
Assets:
Reinsurance assets, net of allowance for credit losses and disputes	$ 36,914		38,971			39,432	36,300
As Previously Reported
Assets:
Deferred income taxes			15,144			12,624
Deferred policy acquisition costs			15,518			9,805
Market risk benefit assets, at fair value			0			0
Other assets			12,714			13,122
Total assets			526,634			586,481
Liabilities:
Future policy benefits for life and accident and health insurance contracts			59,223			56,878
Policyholder contract deposits			158,891			154,470
Market risk benefit liabilities, at fair value			0			0
Other policyholder funds			3,909			3,548
Other liabilities(c)			26,456			27,122
Total liabilities			484,399			519,282
Additional paid-in capital			80,284
Retained earnings			33,032			15,504
Accumulated other comprehensive loss			(22,092)			13,511
Total AIG shareholders’ equity			40,002			66,362
Non-redeemable noncontrolling interests			2,233
Total equity			42,235			67,199
Total liabilities and equity			526,634			586,481
As Previously Reported | Fortitude RE
Assets:
Reinsurance assets, net of allowance for credit losses and disputes			32,159			34,578	$ 29,135
As Previously Reported | Excluding Fortitude
Assets:
Reinsurance assets, net of allowance for credit losses and disputes			39,434			38,963
Cumulative effect adjustments
Assets:
Deferred income taxes			(340)			339
Deferred policy acquisition costs			(2,661)			3,150
Market risk benefit assets, at fair value			796			338
Other assets			(330)			398
Total assets			(4,406)			12,360
Liabilities:
Future policy benefits for life and accident and health insurance contracts			(7,309)			10,486
Policyholder contract deposits			(2,907)			(6,247)
Market risk benefit liabilities, at fair value			4,736			8,739
Other policyholder funds			(446)			248
Other liabilities(c)			301			398
Total liabilities			(5,625)			13,624
Additional paid-in capital			(369)
Retained earnings			1,861			933
Accumulated other comprehensive loss			(524)			(2,197)
Total AIG shareholders’ equity			968			(1,264)
Non-redeemable noncontrolling interests			251
Total equity			1,219			(1,264)
Total liabilities and equity			(4,406)			12,360
Cumulative effect adjustments | Fortitude RE
Assets:
Reinsurance assets, net of allowance for credit losses and disputes			(1,408)			7,666
Cumulative effect adjustments | Excluding Fortitude
Assets:
Reinsurance assets, net of allowance for credit losses and disputes			$ (463)			$ 469

[1] See Note 10 for details of balances associated with variable interest entities.