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
	Mar. 31, 2023	Mar. 31, 2022
Income Statement [Abstract]
Premiums	$ 8,481	$ 7,120
Policy fees	698	730
Total net realized gains (losses)	(1,909)	3,579
Total revenues	10,984	14,944
Policyholder benefits and losses incurred	6,397	5,060
Change in the fair value of market risk benefits, net	196	(233)
Interest credited to policyholder account balances	1,040	879
Amortization of deferred policy acquisition costs	1,293	1,137
General operating and other expenses	1,980	2,164
Total benefits, losses and expenses	11,215	9,230
Income (loss) from continuing operations before income tax expense (benefit)	(231)	5,714
Income tax expense (benefit)	(144)	1,154
Income (loss) from continuing operations	(87)	4,560
Net income (loss)	(87)	4,560
Net income (loss) from continuing operations attributable to noncontrolling interests	(117)	387
Net income (loss) attributable to AIG	30	4,173
Net income (loss) attributable to AIG common shareholders	$ 23	$ 4,166
Income (loss) attributable to AIG common shareholders (in dollars per share)	$ 0.03	$ 5.10
Net income attributable to AIG common shareholders (in dollars per share)	$ 0.03	$ 5.04
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ (87)	$ 4,560
Change in unrealized appreciation (depreciation) of all other investments	4,252	(16,141)
Change in fair value of market risk benefits related to our own credit risk	75	782
Change in the discount rates used to measure traditional and limited payment long-duration insurance contracts	(420)	2,290
Other comprehensive income (loss)	3,913	(13,111)
Comprehensive income (loss)	3,826	(8,551)
Comprehensive income (loss) attributable to noncontrolling interests	509	(625)
Comprehensive income (loss) attributable to AIG	$ 3,317	(7,926)
As Previously Reported
Income Statement [Abstract]
Premiums		7,110
Policy fees		764
Total net realized gains (losses)		4,419
Total revenues		15,808
Policyholder benefits and losses incurred		5,255
Change in the fair value of market risk benefits, net		0
Interest credited to policyholder account balances		877
Amortization of deferred policy acquisition costs		1,437
General operating and other expenses		2,181
Total benefits, losses and expenses		9,973
Income (loss) from continuing operations before income tax expense (benefit)		5,835
Income tax expense (benefit)		1,179
Income (loss) from continuing operations		4,656
Net income (loss)		4,656
Net income (loss) from continuing operations attributable to noncontrolling interests		396
Net income (loss) attributable to AIG		4,260
Net income (loss) attributable to AIG common shareholders		$ 4,253
Income (loss) attributable to AIG common shareholders (in dollars per share)		$ 5.21
Net income attributable to AIG common shareholders (in dollars per share)		$ 5.15
Statement of Comprehensive Income [Abstract]
Net income (loss)		$ 4,656
Change in unrealized appreciation (depreciation) of all other investments		(13,607)
Change in fair value of market risk benefits related to our own credit risk		0
Change in the discount rates used to measure traditional and limited payment long-duration insurance contracts		0
Other comprehensive income (loss)		(13,648)
Comprehensive income (loss)		(8,992)
Comprehensive income (loss) attributable to noncontrolling interests		(665)
Comprehensive income (loss) attributable to AIG		(8,327)
Effect of Change
Income Statement [Abstract]
Premiums		10
Policy fees		(34)
Total net realized gains (losses)		(840)
Total revenues		(864)
Policyholder benefits and losses incurred		(195)
Change in the fair value of market risk benefits, net		(233)
Interest credited to policyholder account balances		2
Amortization of deferred policy acquisition costs		(300)
General operating and other expenses		(17)
Total benefits, losses and expenses		(743)
Income (loss) from continuing operations before income tax expense (benefit)		(121)
Income tax expense (benefit)		(25)
Income (loss) from continuing operations		(96)
Net income (loss)		(96)
Net income (loss) from continuing operations attributable to noncontrolling interests		(9)
Net income (loss) attributable to AIG		(87)
Net income (loss) attributable to AIG common shareholders		$ (87)
Income (loss) attributable to AIG common shareholders (in dollars per share)		$ (0.11)
Net income attributable to AIG common shareholders (in dollars per share)		$ (0.11)
Statement of Comprehensive Income [Abstract]
Net income (loss)		$ (96)
Change in unrealized appreciation (depreciation) of all other investments		(2,534)
Change in fair value of market risk benefits related to our own credit risk		782
Change in the discount rates used to measure traditional and limited payment long-duration insurance contracts		2,290
Other comprehensive income (loss)		537
Comprehensive income (loss)		441
Comprehensive income (loss) attributable to noncontrolling interests		40
Comprehensive income (loss) attributable to AIG		$ 401