Equity - Reclassification of significant items out of accumulated other comprehensive income (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Reclassification of significant items out of Accumulated Other Comprehensive Income
Total net realized gains (losses)	$ 3,392	$ (1,926)	$ 7,811	$ 1,324
Net income attributable to AIG	3,036	99	7,296	3,975
Amount Reclassified from AOCI
Reclassification of significant items out of Accumulated Other Comprehensive Income
Net income attributable to AIG	(611)	124	(758)	501
Unrealized appreciation (depreciation) of fixed maturity securities on which allowance for credit losses was taken | Amount Reclassified from AOCI
Reclassification of significant items out of Accumulated Other Comprehensive Income
Total net realized gains (losses)	(8)	(4)	(8)	(6)
Unrealized appreciation (depreciation) of all other investments | Amount Reclassified from AOCI
Reclassification of significant items out of Accumulated Other Comprehensive Income
Total net realized gains (losses)	(596)	139	(735)	530
Change in retirement plan liabilities adjustment | Amount Reclassified from AOCI
Reclassification of significant items out of Accumulated Other Comprehensive Income
Total net realized gains (losses)	(7)	(11)	(15)	(23)
Prior-service credit | Amount Reclassified from AOCI
Reclassification of significant items out of Accumulated Other Comprehensive Income
Total net realized gains (losses)	0	(1)	(1)	(2)
Actuarial losses | Amount Reclassified from AOCI
Reclassification of significant items out of Accumulated Other Comprehensive Income
Total net realized gains (losses)	$ (7)	$ (10)	$ (14)	$ (21)