Summary of Significant Accounting Policies - Adjusted Balance Sheet to Apply Adopted Guidance (Details) - USD ($) $ in Millions	Mar. 31, 2023		Dec. 31, 2022		Mar. 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 $175 in 2023 and $169 in 2022	$ 15,523		$ 13,243
Reinsurance assets, net of allowance for credit losses and disputes								$ 3,176
Deferred income taxes	14,480		14,804				$ 12,963
Deferred policy acquisition costs	13,304		12,857				12,955
Market risk benefit assets, at fair value	830		796				338	338
Other assets	12,967	[1]	12,384	[1]			13,520
Total assets	536,627		522,228				598,841
Liabilities:
Future policy benefits for life and accident and health insurance contracts	54,846		51,914		$ 59,307		67,364
Policyholder contract deposits	157,896		155,984		152,315		148,223
Market risk benefit liabilities, at fair value	5,144		4,736				8,739	8,739
Other policyholder funds	3,461		3,463				3,796
Other liabilities	28,595	[1]	26,757	[1]			27,520
Total liabilities	490,321		478,774				532,906
Additional paid-in capital	79,562		79,915
Retained earnings	34,690		34,893				16,437
Accumulated other comprehensive loss	(19,329)		(22,616)				11,314
Total AIG shareholders’ equity	43,317		40,970				65,098
Non-redeemable noncontrolling interests	2,989		2,484
Total equity	46,306		43,454		$ 58,666	$ 69,034	65,935
Total liabilities and equity	536,627		522,228				598,841
Fortitude RE
Assets:
Reinsurance assets, net of allowance for credit losses and disputes	31,149		30,751				42,244	36,801
Excluding Fortitude
Assets:
Reinsurance assets, net of allowance for credit losses and disputes	$ 41,706		38,971				39,432	36,300
As Previously Reported
Assets:
Reinsurance assets, net of allowance for credit losses and disputes								2,707
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			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			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 9 for details of balances associated with variable interest entities.