Balance Sheets (ENTERGY MISSISSIPPI, INC.) (Parenthetical) (USD $)	Dec. 31, 2011	Dec. 31, 2010
Common stock, shares authorized	500,000,000	500,000,000
Common stock, shares issued	254,752,788	254,752,788
Entergy Mississippi
Common stock, par value
Common stock, shares authorized	12,000,000	12,000,000
Common stock, shares issued	8,666,357	8,666,357
Common stock, shares outstanding	8,666,357	8,666,357