Asset Retirement Obligations (Details 2) (USD $) In Millions, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Utility [Member] | ANO One And ANO Two [Member]
Fair values of decommissioning trust funds and related asset retirement obligation regulatory assets
Decommissioning Trust Fair Values	$ 541.7	$ 520.8
Regulatory Assets	181.5	161.4
Utility [Member] | River Bend [Member]
Fair values of decommissioning trust funds and related asset retirement obligation regulatory assets
Decommissioning Trust Fair Values	420.9	393.6
Regulatory Assets	5.5	10.9
Utility [Member] | Waterford Three [Member]
Fair values of decommissioning trust funds and related asset retirement obligation regulatory assets
Decommissioning Trust Fair Values	254.0	240.5
Regulatory Assets	116.1	104.2
Utility [Member] | Grand Gulf [Member]
Fair values of decommissioning trust funds and related asset retirement obligation regulatory assets
Decommissioning Trust Fair Values	423.4	387.9
Regulatory Assets	59.6	98.3
Entergy Wholesale Commodities [Member]
Fair values of decommissioning trust funds and related asset retirement obligation regulatory assets
Decommissioning Trust Fair Values	2,148.0	2,052.9
Regulatory Assets	$ 0	$ 0