Summary of Significant Accounting Policies - Adjusted Income Statement and Comprehensive Income to Apply Adopted Guidance (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Income Statement [Abstract]
Premiums	$ 33,254	$ 31,856	$ 31,285
Policy fees	2,797	2,913	3,005
Total net realized gains (losses)	(4,608)	7,064	2,271
Total revenues	46,802	54,450	52,157
Policyholder benefits and losses incurred	24,755	22,176	23,785
Change in the fair value of market risk benefits, net	2	(958)	(447)
Interest credited to policyholder account balances	4,424	3,744	3,570
Amortization of deferred policy acquisition costs	4,808	4,557	4,524
General operating and other expenses	8,499	9,122	8,728
Total benefits, losses and expenses	42,944	40,151	38,810
Income from continuing operations before income tax expense (benefit)	3,858	14,299	13,347
Income tax expense (benefit)	(20)	3,025	2,441
Income from continuing operations	3,878	11,274	10,906
Net income	3,878	11,273	10,906
Net income from continuing operations attributable to noncontrolling interests	235	1,046	539
Net income attributable to AIG	3,643	10,227	10,367
Net income (loss) attributable to AIG common shareholders	$ 3,614	$ 10,198	$ 10,338
Income (loss) attributable to AIG common shareholders (in dollars per share)	$ 5.02	$ 13.10	$ 12.10
Net income attributable to AIG common shareholders (in dollars per share)	$ 4.98	$ 12.94	$ 11.95
Statement of Comprehensive Income [Abstract]
Net income	$ 3,878	$ 11,273	$ 10,906
Change in unrealized appreciation (depreciation) of fixed maturity securities on which allowance for credit losses was taken	14	(94)	44
Change in unrealized appreciation (depreciation) of all other investments	7,134	(38,408)	(7,151)
Change in fair value of market risk benefits attributable to changes in our own credit risk	(544)	1,294	179
Change in the discount rates used to measure traditional and limited payment long-duration insurance contracts	(871)	5,544	1,361
Change in foreign currency translation adjustments	102	(613)	(180)
Other comprehensive income (loss)	5,940	(32,303)	(5,424)
Comprehensive income (loss)	9,818	(21,030)	5,482
Comprehensive income (loss) attributable to noncontrolling interests	1,534	(1,454)	440
Comprehensive income (loss) attributable to AIG	$ 8,284	(19,576)	5,042
As Previously Reported
Income Statement [Abstract]
Premiums		31,857	31,259
Policy fees		2,972	3,051
Total net realized gains (losses)		8,991	2,151
Total revenues		56,437	52,057
Policyholder benefits and losses incurred		22,771	24,388
Change in the fair value of market risk benefits, net		0	0
Interest credited to policyholder account balances		3,709	3,557
Amortization of deferred policy acquisition costs		4,970	4,573
General operating and other expenses		9,195	8,790
Total benefits, losses and expenses		42,155	39,958
Income from continuing operations before income tax expense (benefit)		14,282	12,099
Income tax expense (benefit)		3,006	2,176
Income from continuing operations		11,276	9,923
Net income		11,275	9,923
Net income from continuing operations attributable to noncontrolling interests		999	535
Net income attributable to AIG		10,276	9,388
Net income (loss) attributable to AIG common shareholders		$ 10,247	$ 9,359
Income (loss) attributable to AIG common shareholders (in dollars per share)		$ 13.16	$ 10.95
Net income attributable to AIG common shareholders (in dollars per share)		$ 13.01	$ 10.82
Statement of Comprehensive Income [Abstract]
Net income		$ 11,275	$ 9,923
Change in unrealized appreciation (depreciation) of fixed maturity securities on which allowance for credit losses was taken		(87)	35
Change in unrealized appreciation (depreciation) of all other investments		(32,775)	(6,001)
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		(514)	(187)
Other comprehensive income (loss)		(33,402)	(5,830)
Comprehensive income (loss)		(22,127)	4,093
Comprehensive income (loss) attributable to noncontrolling interests		(1,584)	430
Comprehensive income (loss) attributable to AIG		(20,543)	3,663
Effect of Change
Income Statement [Abstract]
Premiums		(1)	26
Policy fees		(59)	(46)
Total net realized gains (losses)		(1,927)	120
Total revenues		(1,987)	100
Policyholder benefits and losses incurred		(595)	(603)
Change in the fair value of market risk benefits, net		(958)	(447)
Interest credited to policyholder account balances		35	13
Amortization of deferred policy acquisition costs		(413)	(49)
General operating and other expenses		(73)	(62)
Total benefits, losses and expenses		(2,004)	(1,148)
Income from continuing operations before income tax expense (benefit)		17	1,248
Income tax expense (benefit)		19	265
Income from continuing operations		(2)	983
Net income		(2)	983
Net income from continuing operations attributable to noncontrolling interests		47	4
Net income attributable to AIG		(49)	979
Net income (loss) attributable to AIG common shareholders		$ (49)	$ 979
Income (loss) attributable to AIG common shareholders (in dollars per share)		$ (0.06)	$ 1.15
Net income attributable to AIG common shareholders (in dollars per share)		$ (0.07)	$ 1.13
Statement of Comprehensive Income [Abstract]
Net income		$ (2)	$ 983
Change in unrealized appreciation (depreciation) of fixed maturity securities on which allowance for credit losses was taken		(7)	9
Change in unrealized appreciation (depreciation) of all other investments		(5,633)	(1,150)
Change in fair value of market risk benefits attributable to changes in our own credit risk		1,294	179
Change in the discount rates used to measure traditional and limited payment long-duration insurance contracts		5,544	1,361
Change in foreign currency translation adjustments		(99)	7
Other comprehensive income (loss)		1,099	406
Comprehensive income (loss)		1,097	1,389
Comprehensive income (loss) attributable to noncontrolling interests		130	10
Comprehensive income (loss) attributable to AIG		$ 967	$ 1,379