Summary of Significant Accounting Policies (Details Textual) (USD $) In Millions, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Summary of Significant Accounting Policies (Additional Textual) [Abstract]
Depreciation rates on average depreciable property	2.60%	2.60%	2.70%
Depreciation rates on average depreciable utility property	2.50%	2.50%	2.70%
Depreciation rates on average depreciable non-utility property	3.90%	3.70%	3.80%
Accumulated depreciation of non-utility property - for Entergy	$ 214.3	$ 207.6
Construction expenditures included in accounts payable	171
Options outstanding excluded from the calculation of diluted earnings per share	5,712,604	5,380,262	4,368,614
Stock-based Compensation Plans Award vesting period	3 years
Portion of percentage of interest of River Bend plant costs, generation, revenues and expenses operating the Louisiana retail deregulated portion of River Bend	approximately 15 %
Limit above which incremental revenue shared between ratepayers and shareholders	4.6 cents per kWh
Entergy Wholesale Commodities [Member] | Vermont Yankees Operating License [Member]
Summary of Significant Accounting Policies (Textual) [Abstract]
Number of nuclear Power Plants Pending For NRC License Renewals	3
Vermont Yankee [Member]
Summary of Significant Accounting Policies (Textual) [Abstract]
Period of Renewal of operating license by NRC	20 years
Expiry of Operating License	2032
Net carrying value of the plant, including nuclear fuel	$ 465
Entergy Arkansas [Member] | Ouachita Units 1 and 2 [Member]
Summary of Significant Accounting Policies (Textual) [Abstract]
Percentage of ownership	100.00%
Entergy Gulf States Louisiana [Member]
Summary of Significant Accounting Policies (Textual) [Abstract]
Percentage of interest in River Bend by Entergy Gulf States Louisiana	30.00%
Rate at which electricity sold to retail customers	4.6 cents per kWh
Period by which Imputed amount of Construction on River Bend is Amortized	Aug. 01, 2025
Entergy Gulf States Louisiana [Member] | Ouachita Unit 3 [Member]
Summary of Significant Accounting Policies (Textual) [Abstract]
Percentage of ownership	100.00%
System Energy [Member]
Summary of Significant Accounting Policies (Textual) [Abstract]
Leasehold interest held by System Energy	11.50%