Risk Management and Fair Values (Fair Values Of Derivative Instruments) (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2012		Dec. 31, 2011
Other Non-Current Liabilities [Member] | Electricity Swaps And Options [Member] | Entergy Wholesale Commodities [Member] | Designated As Hedging Instrument [Member]
Liabilities:
Derivative Liability, Fair Value	$ 12.0
Derivative liability as hedging instrument offset	(10)
Other Non-Current Liabilities [Member] | Electricity Swaps And Options [Member] | Entergy Wholesale Commodities [Member] | Not Designated As Hedging Instrument [Member]
Liabilities:
Derivative Liability, Fair Value	15.0
Derivative liability as hedging instrument offset	(13)
Other Deferred Debits And Other Assets [Member] | Electricity Swaps And Options [Member] | Entergy Wholesale Commodities [Member] | Designated As Hedging Instrument [Member]
Assets:
Derivative Asset, Fair value	69	[1]	112	[1]
Derivative asset as hedging instrument offset	(13)	[1]	(1)	[1]
Other Deferred Debits And Other Assets [Member] | Electricity Swaps And Options [Member] | Entergy Wholesale Commodities [Member] | Not Designated As Hedging Instrument [Member]
Assets:
Derivative Asset, Fair value	23	[1]
Derivative asset as hedging instrument offset	(11)	[1]
Prepayments And Other [Member] | Electricity Swaps And Options [Member] | Entergy Wholesale Commodities [Member] | Designated As Hedging Instrument [Member]
Assets:
Derivative Asset, Fair value	140	[1]	197	[1]
Derivative asset as hedging instrument offset	(9)	[1]	(25)	[1]
Prepayments And Other [Member] | Electricity Swaps And Options [Member] | Entergy Wholesale Commodities [Member] | Not Designated As Hedging Instrument [Member]
Assets:
Derivative Asset, Fair value	25	[1]	37	[1]
Derivative asset as hedging instrument offset	(2)	[1]	(8)	[1]
Prepayments And Other [Member] | Natural Gas Swaps [Member] | Utility [Member] | Not Designated As Hedging Instrument [Member]
Liabilities:
Derivative Liability, Fair Value	10.0
Other Current Liabilities [Member] | Electricity Swaps And Options [Member] | Entergy Wholesale Commodities [Member] | Designated As Hedging Instrument [Member]
Liabilities:
Derivative Liability, Fair Value			1.0	[1]
Derivative liability as hedging instrument offset			(1)	[1]
Other Current Liabilities [Member] | Electricity Swaps And Options [Member] | Entergy Wholesale Commodities [Member] | Not Designated As Hedging Instrument [Member]
Liabilities:
Derivative Liability, Fair Value	11.0		33.0	[1]
Derivative liability as hedging instrument offset	(11)		(33)	[1]
Other Current Liabilities [Member] | Swap [Member] | Utility [Member] | Not Designated As Hedging Instrument [Member]
Liabilities:
Derivative Liability, Fair Value			30.0	[1]
Derivative liability as hedging instrument offset				[1]
Entergy Gulf States Louisiana [Member] | Not Designated As Hedging Instrument [Member]
Liabilities:
Derivative Liability, Fair Value	3.0		8.6
Entergy Louisiana [Member] | Not Designated As Hedging Instrument [Member]
Liabilities:
Derivative Liability, Fair Value	4.8		12.4
Entergy Mississippi [Member] | Not Designated As Hedging Instrument [Member]
Liabilities:
Derivative Liability, Fair Value	2.3
Entergy Mississippi [Member] | Other Current Liabilities [Member] | Natural Gas Swaps [Member] | Not Designated As Hedging Instrument [Member]
Liabilities:
Derivative Liability, Fair Value			7.8
Entergy New Orleans | Other Current Liabilities [Member] | Natural Gas Swaps [Member] | Not Designated As Hedging Instrument [Member]
Liabilities:
Derivative Liability, Fair Value			$ 1.5

[1] The balances of derivative assets and liabilities in these tables are presented gross. Certain investments, including those not designated as hedging instruments, are subject to master netting agreements and are presented on the Entergy Consolidated Balance Sheets on a net basis in accordance with accounting guidance for Derivatives and Hedging