Segment Information - Schedule of Continuing Operations by Operating Segment (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Segment Reporting Information [Line Items]
Net Premiums Earned	$ 6,073	$ 5,945	$ 17,720	$ 17,564
Loss and Loss Adjustment Expenses Incurred	3,391	3,773	10,678	10,753
Amortization of DAC	850	863	2,522	2,543
General Operating Expense	1,297	1,346	3,574	4,194
Net Investment Income	772	973	3,343	2,942
Income from continuing operations before income tax expense	714	649	3,218	2,324
Interest expense	99	112	291	353
Changes in the fair values of equity securities, AIG's investment in Corebridge and gain/loss on sale of shares	(288)	25	393	172
Other income (expense) - net				16
Gain (loss) on extinguishment of debt	0	0	5	(1)
Total net realized losses	(490)	(167)	(851)	(434)
Net realized gains (losses), net investment income	(2)	0	(4)	6
Net realized gains (losses), reconciliation to income (loss) from continuing operations before income tax expense	(433)	7	(690)	(234)
Net gain on divestitures and other	0	(8)	53	94
Non-operating litigation reserves and settlements, reconciliation to income (loss) from continuing operations before income tax expense			13
(Unfavorable) favorable prior year development and related amortization changes ceded under retroactive reinsurance agreements	9	(126)	(53)	(66)
Net loss reserve discount benefit (charge)	2	(29)	(27)	(131)
Net results of businesses in run-off, net investment income	9	5	22	13
Net results of businesses in run-off, net investment income, reconciliation to income (loss) from continuing operations before income tax expense	1	(8)	8	4
Non-operating pension expenses	(6)		(16)
Integration and transaction costs associated with acquiring or divesting businesses	(7)	(22)	(13)	(37)
Restructuring and other costs	$ (153)	$ (137)	$ (307)	$ (630)
Restructuring Charges, Statement of Income or Comprehensive Income [Extensible Enumeration]	General Operating Expense	General Operating Expense	General Operating Expense	General Operating Expense
Non-recurring costs related to regulatory or accounting changes	$ (3)	$ (4)	$ (10)	$ (15)
Fortitude Re funds withheld assets
Segment Reporting Information [Line Items]
Net Investment Income	29	51	108	123
Total net realized losses	(5)	(18)	(59)	(38)
Fortitude Re funds withheld embedded derivative
Segment Reporting Information [Line Items]
Total net realized losses	(54)	(157)	(109)	(158)
Total
Segment Reporting Information [Line Items]
Net Investment Income	1,024	892	2,824	2,612
Income from continuing operations before income tax expense	1,622	1,075	3,922	3,241
Reportable Segments
Segment Reporting Information [Line Items]
Net Premiums Written	6,230	6,380	17,636	17,825
Net Premiums Earned	6,040	5,947	17,687	17,482
Loss and Loss Adjustment Expenses Incurred	3,379	3,611	10,573	10,472
Amortization of DAC	851	863	2,522	2,532
Other Acquisition Cost	237	292	670	825
General Operating Expense	780	744	2,260	2,190
Underwriting Income (Loss)	793	437	1,662	1,463
Net Investment Income	945	773	2,552	2,281
Income from continuing operations before income tax expense	1,738	1,210	4,214	3,744
Interest expense	(100)	(110)	(292)	(336)
Other Operations
Segment Reporting Information [Line Items]
Net Investment Income	77	120	273	332
Income from continuing operations before income tax expense	(18)	(28)	0	(164)
Elimination and consolidations
Segment Reporting Information [Line Items]
Net Investment Income	2	(1)	(1)	(1)
Income from continuing operations before income tax expense	2	3	0	(3)
North America Commercial | Reportable Segments
Segment Reporting Information [Line Items]
Net Premiums Written	2,435	2,445	6,472	6,228
Net Premiums Earned	2,198	2,123	6,455	6,046
Loss and Loss Adjustment Expenses Incurred	1,303	1,532	4,169	4,109
Amortization of DAC	221	206	654	615
Other Acquisition Cost	44	64	137	164
General Operating Expense	246	225	681	635
Underwriting Income (Loss)	384	96	814	523
International Commercial | Reportable Segments
Segment Reporting Information [Line Items]
Net Premiums Written	2,115	2,052	6,467	6,275
Net Premiums Earned	2,188	2,039	6,363	6,081
Loss and Loss Adjustment Expenses Incurred	1,167	1,092	3,515	3,381
Amortization of DAC	285	259	799	753
Other Acquisition Cost	96	96	274	266
General Operating Expense	310	272	905	801
Underwriting Income (Loss)	330	320	870	880
Global Personal | Reportable Segments
Segment Reporting Information [Line Items]
Net Premiums Written	1,680	1,883	4,697	5,322
Net Premiums Earned	1,654	1,785	4,869	5,355
Loss and Loss Adjustment Expenses Incurred	909	987	2,889	2,982
Amortization of DAC	345	398	1,069	1,164
Other Acquisition Cost	97	132	259	395
General Operating Expense	224	247	674	754
Underwriting Income (Loss)	$ 79	$ 21	$ (22)	$ 60