BASIS OF PRESENTATION (Details) $ / shares in Units, $ in Millions					3 Months Ended										12 Months Ended
	Nov. 13, 2018 USD ($)	Jul. 18, 2018 USD ($)	Nov. 14, 2016 USD ($)	Sep. 16, 2016 USD ($)	Dec. 31, 2018 USD ($) item $ / shares	Sep. 30, 2018 USD ($)	Jun. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2017 USD ($) $ / shares	Sep. 30, 2017 USD ($)	Jun. 30, 2017 USD ($)	Mar. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Sep. 30, 2016 USD ($)	Dec. 31, 2018 USD ($) item $ / shares	Dec. 31, 2017 USD ($) $ / shares	Dec. 31, 2016 USD ($)	Nov. 17, 2016 USD ($)	Aug. 31, 2016 USD ($)
Basis of Presentation [Line Items]
Common stock, par value (in dollars per share) | $ / shares					$ 2.5				$ 2.5						$ 2.5	$ 2.5
Net income (loss) attributable to AIG					$ (622)	$ (1,259)	$ 937	$ 938	$ (6,660)	$ (1,739)	$ 1,130	$ 1,185			$ (6)	$ (6,084)	$ (849)
Income (loss) from continuing operations before income tax expense					(695)	(1,527)	1,252	1,227	875	(2,803)	1,667	1,727			257	1,466	(74)
Net income (loss) on sale of divested businesses					(3)	(2)	(25)	(8)	$ (241)	13	$ 60	$ 100			38	68	545
Repayments of Long-term Debt															3,672	3,698	4,082
Other Income															$ 1,638	2,412	3,121
Fortitude Holdings
Basis of Presentation [Line Items]
Contingent consideration period															18 months
Validus Holding Ltd [Member]
Basis of Presentation [Line Items]
Payments to Acquire Business		$ 5,475
Net income (loss) attributable to AIG															$ (206)
Interest acquired		100.00%
Adjustment
Basis of Presentation [Line Items]
Net income (loss) attributable to AIG					(87)	$ (40)	$ 0	$ 0
Income (loss) from continuing operations before income tax expense					(132)
Adjustments 2016
Basis of Presentation [Line Items]
Net income (loss) attributable to AIG																	(174)
Income (loss) from continuing operations before income tax expense																	(57)
Adjustments 2018
Basis of Presentation [Line Items]
Net income (loss) attributable to AIG															(77)	95	117
Income (loss) from continuing operations before income tax expense															(98)
NSM
Basis of Presentation [Line Items]
Total consideration																			$ 201
Net income (loss) on sale of divested businesses														$ 105
Ascot
Basis of Presentation [Line Items]
Consideration in cash																	244
Total consideration				$ 1,100
Net income (loss) on sale of divested businesses				$ 162
Voting interest in subsidiary, Percent				100.00%
Ownership reflecting consideration, Percent				20.00%
United Guaranty Asia
Basis of Presentation [Line Items]
Consideration in cash										$ 40							2,200
Non-cash consideration received from sale															0	$ 0	1,101
Total consideration													$ 3,300				3,300
Net income (loss) on sale of divested businesses																	$ 697
Voting interest in subsidiary, Percent													100.00%				100.00%
Dividend-in-lieu													$ 261
Cash consideration retained by buyer																	$ 40
Korea Fund
Basis of Presentation [Line Items]
Income (loss) from continuing operations before income tax expense																	464
Total consideration																		$ 2,500
Repayments of Long-term Debt																	1,200
Other Income																	$ 1,100
AIG Fuji Life Insurance
Basis of Presentation [Line Items]
Consideration in cash			$ 333
Fortitude Holdings
Basis of Presentation [Line Items]
Consideration in cash	$ 381
Contingent consideration receivable, maximum					100										100
Contingent condieration receivable					$ 95										$ 95
Minimum
Basis of Presentation [Line Items]
Number of Countries in which the entity operates | item					80										80
TC Group Cayman | Fortitude Holdings
Basis of Presentation [Line Items]
Voting interest in subsidiary, Percent	19.90%
American International Group, Inc. | Fortitude Holdings
Basis of Presentation [Line Items]
Percentage of common stock held after closing of transaction	80.10%
Fortitude Holdings | Fortitude RE
Basis of Presentation [Line Items]
Parent owneship interest					100.00%										100.00%