Risk Management and Fair Values (Fair Values Of Derivative Instruments) (Details) (USD $) In Millions, unless otherwise specified	9 Months Ended	12 Months Ended
	Sep. 30, 2013	Dec. 31, 2012
Assets:
Derivative asset as hedging instrument offset	$ (7)	$ (56)
Other Non-Current Liabilities [Member] | Electricity Swaps And Options [Member] | Entergy Wholesale Commodities [Member] | Designated As Hedging Instrument [Member]
Liabilities:
Derivative Liability, Fair Value, Net Liability	4	7
Derivative Liability, Fair Value, Gross Liability	11.0	18.0
Derivative liability as hedging instrument offset	(7)	(11)
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, Net Liability	9	6
Derivative Liability, Fair Value, Gross Liability	16.0	19.0
Derivative liability as hedging instrument offset	(7)	(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, Net Asset	5	36
Derivative Asset, Fair Value, Gross Asset	12	46
Derivative asset as hedging instrument offset	(7)	(10)
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, Net Asset	8	10
Derivative Asset, Fair Value, Gross Asset	15	24
Derivative asset as hedging instrument offset	(7)	(14)
Prepayments And Other [Member] | Electricity Swaps And Options [Member] | Entergy Wholesale Commodities [Member] | Designated As Hedging Instrument [Member]
Assets:
Derivative Asset, Fair Value, Net Asset	22	123
Derivative Asset, Fair Value, Gross Asset	50	123
Derivative asset as hedging instrument offset	(28)
Prepayments And Other [Member] | Electricity Swaps And Options [Member] | Entergy Wholesale Commodities [Member] | Not Designated As Hedging Instrument [Member]
Assets:
Derivative Asset, Fair Value, Net Asset	50	22
Derivative Asset, Fair Value, Gross Asset	78	22
Derivative asset as hedging instrument offset	(28)
Other Current Liabilities [Member] | Electricity Swaps And Options [Member] | Entergy Wholesale Commodities [Member] | Designated As Hedging Instrument [Member]
Liabilities:
Derivative Liability, Fair Value, Net Liability	13
Derivative Liability, Fair Value, Gross Liability	40.0
Derivative liability as hedging instrument offset	(27)
Other Current Liabilities [Member] | Electricity Swaps And Options [Member] | Entergy Wholesale Commodities [Member] | Not Designated As Hedging Instrument [Member]
Liabilities:
Derivative Liability, Fair Value, Net Liability	10
Derivative Liability, Fair Value, Gross Liability	39.0
Derivative liability as hedging instrument offset	(29)
Other Current Liabilities [Member] | Natural Gas Swaps [Member] | Utility [Member] | Not Designated As Hedging Instrument [Member]
Liabilities:
Derivative Liability, Fair Value, Net Liability	3	8
Derivative Liability, Fair Value, Gross Liability	3.0	8.0
Entergy Gulf States Louisiana [Member] | Other Current Liabilities [Member] | Natural Gas Swaps [Member] | Utility [Member] | Not Designated As Hedging Instrument [Member]
Liabilities:
Derivative Liability, Fair Value, Gross Liability	1.3	2.6
Entergy Louisiana [Member] | Other Current Liabilities [Member] | Natural Gas Swaps [Member] | Utility [Member] | Not Designated As Hedging Instrument [Member]
Liabilities:
Derivative Liability, Fair Value, Gross Liability	1.4	3.4
Entergy Mississippi [Member] | Other Current Liabilities [Member] | Natural Gas Swaps [Member] | Utility [Member] | Not Designated As Hedging Instrument [Member]
Liabilities:
Derivative Liability, Fair Value, Gross Liability	0.3	2.2
Entergy New Orleans | Other Current Liabilities [Member] | Natural Gas Swaps [Member] | Utility [Member] | Not Designated As Hedging Instrument [Member]
Liabilities:
Derivative Liability, Fair Value, Gross Liability	$ 0.2