EARNINGS PER COMMON SHARE (EPS) (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Numerator for EPS:
Income (loss) from continuing operations	$ (5,833)	$ 4,121	$ 103
Less: Net income from continuing operations attributable to noncontrolling interests	115	821	67
Less: Preferred stock dividends	29	22	0
Income (loss) attributable to AIG common shareholders from continuing operations	(5,977)	3,278	36
Income (loss) from discontinued operations, net of income tax expense	4	48	(42)
Net income (loss) attributable to AIG common shareholders	$ (5,973)	$ 3,326	$ (6)
Denominator for EPS:
Weighted average common shares outstanding - basic	869,309,458	876,750,264	898,405,537
Dilutive common shares	0	12,761,682	11,735,705
Weighted average common shares outstanding - diluted	869,309,458	889,511,946	910,141,242
Basic:
Income (loss) from continuing operations	$ (6.88)	$ 3.74	$ 0.04
Income from discontinued operations	0	0.05	(0.05)
Income (loss) attributable to AIG common shareholders	(6.88)	3.79	(0.01)
Diluted:
Income (loss) from continuing operations	(6.88)	3.69	0.04
Income from discontinued operations	0	0.05	(0.05)
Income (loss) attributable to AIG common shareholders	$ (6.88)	$ 3.74	$ (0.01)
Dilutive shares excluded from computation of diluted earnings per share	5,401,597
Number of shares excluded from diluted shares outstanding because the effect would have been anti-dilutive	68,700,000	20,000,000.0	19,600,000