Summary of Significant Accounting Policies - Adjusted Income Statement and Comprehensive Income to Apply Adopted Guidance (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Income Statement [Abstract]
Premiums	$ 9,057	$ 7,512	$ 17,538	$ 14,632
Policy fees	694	728	1,392	1,458
Total net realized gains (losses)	(297)	2,632	(2,206)	6,211
Total revenues	13,218	13,663	24,202	28,607
Policyholder benefits and losses incurred	6,858	4,984	13,255	10,044
Change in the fair value of market risk benefits, net	(262)	(45)	(66)	(278)
Interest credited to policyholder account balances	1,062	911	2,102	1,790
Amortization of deferred policy acquisition costs	1,190	1,116	2,483	2,253
General operating and other expenses	2,268	2,206	4,248	4,370
Total benefits, losses and expenses	11,351	9,738	22,566	18,968
Income (loss) from continuing operations before income tax expense (benefit)	1,867	3,925	1,636	9,639
Income tax expense (benefit)	176	845	32	1,999
Income (loss) from continuing operations	1,691	3,080	1,604	7,640
Net income (loss)	1,691	3,079	1,604	7,639
Net income (loss) from continuing operations attributable to noncontrolling interests	198	325	81	712
Net income (loss) attributable to AIG	1,493	2,754	1,523	6,927
Net income attributable to AIG common shareholders	$ 1,485	$ 2,746	$ 1,508	$ 6,912
Income (loss) attributable to AIG common shareholders (in dollars per share)	$ 2.05	$ 3.47	$ 2.06	$ 8.60
Net income attributable to AIG common shareholders (in dollars per share)	$ 2.03	$ 3.43	$ 2.05	$ 8.50
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 1,691	$ 3,079	$ 1,604	$ 7,639
Change in unrealized appreciation (depreciation) of fixed maturity securities on which allowance for credit losses was taken	84	36	90	(9)
Change in unrealized appreciation (depreciation) of all other investments	(1,998)	(14,782)	2,254	(30,923)
Change in fair value of market risk benefits attributable to changes in our own credit risk	(190)	582	(115)	1,364
Change in the discount rates used to measure traditional and limited payment long-duration insurance contracts	373	1,870	(47)	4,160
Change in foreign currency translation adjustments	(59)	(335)	(87)	(341)
Other comprehensive income (loss)	(1,738)	(12,617)	2,175	(25,728)
Comprehensive income (loss)	(47)	(9,538)	3,779	(18,089)
Comprehensive income (loss) attributable to noncontrolling interests	(60)	(673)	449	(1,298)
Comprehensive income (loss) attributable to AIG	$ 13	(8,865)	$ 3,330	(16,791)
As Previously Reported
Income Statement [Abstract]
Premiums		7,516		14,626
Policy fees		742		1,506
Total net realized gains (losses)		3,392		7,811
Total revenues		14,441		30,249
Policyholder benefits and losses incurred		5,123		10,378
Change in the fair value of market risk benefits, net		0		0
Interest credited to policyholder account balances		910		1,787
Amortization of deferred policy acquisition costs		1,298		2,735
General operating and other expenses		2,223		4,404
Total benefits, losses and expenses		10,120		20,093
Income (loss) from continuing operations before income tax expense (benefit)		4,321		10,156
Income tax expense (benefit)		928		2,107
Income (loss) from continuing operations		3,393		8,049
Net income (loss)		3,392		8,048
Net income (loss) from continuing operations attributable to noncontrolling interests		356		752
Net income (loss) attributable to AIG		3,036		7,296
Net income attributable to AIG common shareholders		$ 3,028		$ 7,281
Income (loss) attributable to AIG common shareholders (in dollars per share)		$ 3.83		$ 9.06
Net income attributable to AIG common shareholders (in dollars per share)		$ 3.78		$ 8.95
Statement of Comprehensive Income [Abstract]
Net income (loss)		$ 3,392		$ 8,048
Change in unrealized appreciation (depreciation) of fixed maturity securities on which allowance for credit losses was taken		40		(5)
Change in unrealized appreciation (depreciation) of all other investments		(12,538)		(26,145)
Change in fair value of market risk benefits attributable to changes in our own credit risk		0		0
Change in the discount rates used to measure traditional and limited payment long-duration insurance contracts		0		0
Change in foreign currency translation adjustments		(281)		(286)
Other comprehensive income (loss)		(12,767)		(26,415)
Comprehensive income (loss)		(9,375)		(18,367)
Comprehensive income (loss) attributable to noncontrolling interests		(655)		(1,320)
Comprehensive income (loss) attributable to AIG		(8,720)		(17,047)
Effect of Change
Income Statement [Abstract]
Premiums		(4)		6
Policy fees		(14)		(48)
Total net realized gains (losses)		(760)		(1,600)
Total revenues		(778)		(1,642)
Policyholder benefits and losses incurred		(139)		(334)
Change in the fair value of market risk benefits, net		(45)		(278)
Interest credited to policyholder account balances		1		3
Amortization of deferred policy acquisition costs		(182)		(482)
General operating and other expenses		(17)		(34)
Total benefits, losses and expenses		(382)		(1,125)
Income (loss) from continuing operations before income tax expense (benefit)		(396)		(517)
Income tax expense (benefit)		(83)		(108)
Income (loss) from continuing operations		(313)		(409)
Net income (loss)		(313)		(409)
Net income (loss) from continuing operations attributable to noncontrolling interests		(31)		(40)
Net income (loss) attributable to AIG		(282)		(369)
Net income attributable to AIG common shareholders		$ (282)		$ (369)
Income (loss) attributable to AIG common shareholders (in dollars per share)		$ (0.36)		$ (0.46)
Net income attributable to AIG common shareholders (in dollars per share)		$ (0.35)		$ (0.45)
Statement of Comprehensive Income [Abstract]
Net income (loss)		$ (313)		$ (409)
Change in unrealized appreciation (depreciation) of fixed maturity securities on which allowance for credit losses was taken		(4)		(4)
Change in unrealized appreciation (depreciation) of all other investments		(2,244)		(4,778)
Change in fair value of market risk benefits attributable to changes in our own credit risk		582		1,364
Change in the discount rates used to measure traditional and limited payment long-duration insurance contracts		1,870		4,160
Change in foreign currency translation adjustments		(54)		(55)
Other comprehensive income (loss)		150		687
Comprehensive income (loss)		(163)		278
Comprehensive income (loss) attributable to noncontrolling interests		(18)		22
Comprehensive income (loss) attributable to AIG		$ (145)		$ 256