Consolidated Balance Sheet (Parenthetical - equity) (USD $)	Mar. 31, 2012	Dec. 31, 2011
AIG shareholders' equity:
Common stock, par value (in dollars per share)	2.50	2.50
Common stock, shares authorized	5,000,000,000	5,000,000,000
Common stock, shares issued	1,906,614,552	1,906,568,099
Treasury stock, shares of common stock	113,167,239	9,746,617
Common Stock
AIG shareholders' equity:
Common stock, shares issued	1,906,614,552	1,906,568,099
Series G | Preferred Stock
AIG shareholders' equity:
Preferred stock, shares issued	0	0
Series E | Preferred Stock
AIG shareholders' equity:
Preferred stock, shares issued	0	0
Series F | Preferred Stock
AIG shareholders' equity:
Preferred stock, shares issued	0	0
Series C | Preferred Stock
AIG shareholders' equity:
Preferred stock, shares issued	0	0