Balance Sheets (SYSTEM ENERGY RESOURCES, 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
System Energy
Common stock, par value
Common stock, shares authorized	1,000,000	1,000,000
Common stock, shares issued	789,350	789,350
Common stock, shares outstanding	789,350	789,350