Asset Retirement Obligations (Narrative) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013	Mar. 31, 2013	Jun. 30, 2012	Sep. 30, 2014	Sep. 30, 2013	Mar. 31, 2014
Decommissioning Fund Investments	$ 5,370,932,000	$ 4,903,144,000
Present value of the difference between the stipulated contract amount for decommissioning the plants less the decommissioning cost	599,900,000
Entergy Louisiana [Member]
Decommissioning Fund Investments	383,615,000	347,274,000
System Energy [Member]
Decommissioning Fund Investments	679,840,000	603,896,000
Entergy Wholesale Commodities [Member]
Reduction in decommissioning liability			46,600,000	60,600,000
Decommissioning expense				49,000,000
Entergy Arkansas [Member]
Decommissioning Fund Investments	769,883,000	710,913,000
Entergy Gulf States Louisiana [Member]
Decommissioning Fund Investments	637,744,000	573,744,000
Vermont Yankee [Member] | Entergy Wholesale Commodities [Member]
Increase in decommissioning liability		27,200,000			101,600,000	58,000,000
Grand Gulf [Member] | System Energy [Member]
Increase in decommissioning liability	99,900,000	102,300,000
Waterford 3 [Member] | Entergy Louisiana [Member]
Increase in decommissioning liability		39,400,000
ANO 1 and 2 [Member] | Entergy Arkansas [Member]
Increase in decommissioning liability							47,600,000
River Bend [Member] | Entergy Gulf States Louisiana [Member]
Increase in decommissioning liability	$ 20,000,000