BASIS OF PRESENTATION (Details) $ / shares in Units, $ in Millions		3 Months Ended		9 Months Ended
	Jul. 18, 2018 USD ($)	Sep. 30, 2018 USD ($) item $ / shares	Sep. 30, 2017 USD ($)	Sep. 30, 2018 USD ($) item $ / shares	Sep. 30, 2017 USD ($)	Dec. 31, 2017 $ / shares
Basis of Presentation [Line Items]
Common Stock, Par or Stated Value Per Share | $ / shares		$ 2.5		$ 2.5		$ 2.5
Net income (loss) attributable to AIG		$ (1,259)	$ (1,739)	$ 616	$ 576
Income (loss) from continuing operations before income tax expense (benefit)		(1,527)	$ (2,803)	952	$ 591
Validus Holding Ltd [Member]
Basis of Presentation [Line Items]
Payments to Acquire Business	$ 5,475
Net income (loss) attributable to AIG		(105)		(105)
Scenario Adjustment [Member]
Basis of Presentation [Line Items]
Net income (loss) attributable to AIG		(205)		(28)
Income (loss) from continuing operations before income tax expense (benefit)		(253)		(15)
Adjusted Pre-Tax Income (Loss)		$ 0		$ 0
Minimum
Basis of Presentation [Line Items]
Number of Countries in which Entity Operates | item		80		80