Risk Management and Fair Values (Fair Values Of Derivative Instruments) (Details) (USD $) In Millions, unless otherwise specified	6 Months Ended	12 Months Ended
	Jun. 30, 2013	Dec. 31, 2012
Assets:
Derivative asset as hedging instrument offset	$ (29)	$ (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	1	7
Derivative Liability, Fair Value, Gross Liability	9.0	18.0
Derivative liability as hedging instrument offset	(8)	(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	2	6
Derivative Liability, Fair Value, Gross Liability	6.0	19.0
Derivative liability as hedging instrument offset	(4)	(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	19	36
Derivative Asset, Fair Value, Gross Asset	27	46
Derivative asset as hedging instrument offset	(8)	(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	3	10
Derivative Asset, Fair Value, Gross Asset	8	24
Derivative asset as hedging instrument offset	(5)	(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	49	123
Derivative Asset, Fair Value, Gross Asset	70	123
Derivative asset as hedging instrument offset	(21)
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	23	22
Derivative Asset, Fair Value, Gross Asset	39	22
Derivative asset as hedging instrument offset	(16)
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	7
Derivative Liability, Fair Value, Gross Liability	20.0
Derivative liability as hedging instrument offset	(13)
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	1
Derivative Liability, Fair Value, Gross Liability	24.0
Derivative liability as hedging instrument offset	(23)
Other Current Liabilities [Member] | Natural Gas Swaps [Member] | Utility [Member] | Not Designated As Hedging Instrument [Member]
Liabilities:
Derivative Liability, Fair Value, Net Liability	7	8
Derivative Liability, Fair Value, Gross Liability	7.0	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	2.1	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	2.8	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	1.7	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	$ 0.1