Segment Information - Schedule of Continuing Operations by Operating Segment (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Segment Reporting Information [Line Items]
Net Premiums Earned	$ 5,877	$ 5,748	$ 11,647	$ 11,619
Loss and Loss Adjustment Expenses Incurred	3,493	3,467	7,287	6,980
Amortization of DAC	847	842	1,672	1,680
General Operating Expense	1,162	1,610	2,277	2,848
Net Investment Income	1,466	990	2,571	1,969
Income from continuing operations before income tax expense	1,544	617	2,504	1,675
Interest expense	100	125	192	241
Changes in the fair values of equity securities, AIG's investment in Corebridge and gain on sale of shares	464	59	681	147
Other income (expense) - net		15		16
Gain (loss) on extinguishment of debt	5	(1)	5	(1)
Total net realized losses	(258)	(180)	(361)	(267)
Net realized gains (losses), net investment income	0	(1)	(2)	6
Net realized gains (losses), reconciliation to income (loss) from continuing operations before income tax expense	(191)	(186)	(257)	(241)
Net gain on divestitures and other	50	102	53	102
Non-operating litigation reserves and settlements, reconciliation to income (loss) from continuing operations before income tax expense	2		13
(Unfavorable) favorable prior year development and related amortization changes ceded under retroactive reinsurance agreements	(53)	62	(62)	60
Net loss reserve discount charge	(12)	(26)	(29)	(102)
Net results of businesses in run-off, net investment income	8	5	13	8
Net results of businesses in run-off, net investment income, reconciliation to income (loss) from continuing operations before income tax expense	2	5	7	12
Non-operating pension expenses	(5)		(10)
Integration and transaction costs associated with acquiring or divesting businesses	(1)	(18)	(6)	(15)
Restructuring and other costs	$ (78)	$ (426)	$ (154)	$ (493)
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)	$ (7)	$ (7)	$ (11)
Fortitude Re funds withheld assets
Segment Reporting Information [Line Items]
Net Investment Income	39	33	79	72
Total net realized losses	(52)	(1)	(54)	(20)
Fortitude Re funds withheld embedded derivative
Segment Reporting Information [Line Items]
Total net realized losses	(14)	8	(55)	(1)
Total
Segment Reporting Information [Line Items]
Net Investment Income	955	879	1,800	1,720
Income from continuing operations before income tax expense	1,391	1,013	2,300	2,166
Reportable Segments
Segment Reporting Information [Line Items]
Net Premiums Written	6,880	6,933	11,406	11,445
Net Premiums Earned	5,878	5,749	11,647	11,535
Loss and Loss Adjustment Expenses Incurred	3,428	3,508	7,194	6,861
Amortization of DAC	846	841	1,671	1,669
Other Acquisition Cost	201	258	433	533
General Operating Expense	777	712	1,480	1,446
Underwriting Income (Loss)	626	430	869	1,026
Net Investment Income	871	746	1,607	1,508
Income from continuing operations before income tax expense	1,497	1,176	2,476	2,534
Interest expense	(101)	(111)	(192)	(226)
Other Operations
Segment Reporting Information [Line Items]
Net Investment Income	88	136	196	212
Income from continuing operations before income tax expense	(3)	(47)	18	(136)
Elimination and consolidations
Segment Reporting Information [Line Items]
Net Investment Income	(4)	(3)	(3)	0
Income from continuing operations before income tax expense	(2)	(5)	(2)	(6)
North America Commercial | Reportable Segments
Segment Reporting Information [Line Items]
Net Premiums Written	2,863	2,750	4,037	3,783
Net Premiums Earned	2,133	1,940	4,257	3,923
Loss and Loss Adjustment Expenses Incurred	1,340	1,307	2,866	2,577
Amortization of DAC	206	189	433	409
Other Acquisition Cost	46	63	93	100
General Operating Expense	240	190	435	410
Underwriting Income (Loss)	301	191	430	427
International Commercial | Reportable Segments
Segment Reporting Information [Line Items]
Net Premiums Written	2,325	2,284	4,352	4,223
Net Premiums Earned	2,124	2,031	4,175	4,042
Loss and Loss Adjustment Expenses Incurred	1,170	1,201	2,348	2,289
Amortization of DAC	269	250	514	494
Other Acquisition Cost	84	81	178	170
General Operating Expense	301	269	595	529
Underwriting Income (Loss)	300	230	540	560
Global Personal | Reportable Segments
Segment Reporting Information [Line Items]
Net Premiums Written	1,692	1,899	3,017	3,439
Net Premiums Earned	1,621	1,778	3,215	3,570
Loss and Loss Adjustment Expenses Incurred	918	1,000	1,980	1,995
Amortization of DAC	371	402	724	766
Other Acquisition Cost	71	114	162	263
General Operating Expense	236	253	450	507
Underwriting Income (Loss)	$ 25	$ 9	$ (101)	$ 39