Risk Management and Fair Values (Fair Values Of Derivative Instruments) (Details) - USD ($) $ in Millions	Mar. 31, 2017	Dec. 31, 2016
Assets:
Derivative asset as hedging instrument offset	$ (3.0)	$ (2.0)
Other Non-Current Liabilities [Member] | Electricity Swaps And Options [Member] | Entergy Wholesale Commodities [Member] | Designated As Hedging Instrument [Member]
Liabilities:
Derivative liability as hedging instrument offset	(9.0)	(7.0)
Derivative Liability, Fair Value, Gross Liability	13.0	16.0
Derivative Liability	4.0	9.0
Other Non-Current Liabilities [Member] | Electricity Swaps And Options [Member] | Entergy Wholesale Commodities [Member] | Not Designated As Hedging Instrument [Member]
Liabilities:
Derivative liability as hedging instrument offset	(2.0)	(4.0)
Derivative Liability, Fair Value, Gross Liability	2.0	4.0
Derivative Liability	0.0	0.0
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, Gross Asset	16.0	6.0
Derivative asset as hedging instrument offset	(9.0)	(6.0)
Derivative Asset	7.0	0.0
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, Gross Asset	2.0	5.0
Derivative asset as hedging instrument offset	(1.0)	(5.0)
Derivative Asset	1.0	0.0
Prepayments And Other [Member] | Electricity Swaps And Options [Member] | Entergy Wholesale Commodities [Member] | Designated As Hedging Instrument [Member]
Assets:
Derivative Asset, Fair Value, Gross Asset	13.0	25.0
Derivative asset as hedging instrument offset	(13.0)	(14.0)
Derivative Asset	0.0	11.0
Prepayments And Other [Member] | Electricity Swaps And Options [Member] | Entergy Wholesale Commodities [Member] | Not Designated As Hedging Instrument [Member]
Assets:
Derivative Asset, Fair Value, Gross Asset	20.0	18.0
Derivative asset as hedging instrument offset	(5.0)	(13.0)
Derivative Asset	15.0	5.0
Prepayments And Other [Member] | Natural Gas Swaps [Member] | Utility [Member] | Not Designated As Hedging Instrument [Member]
Assets:
Derivative Asset, Fair Value, Gross Asset	5.0	13.0
Derivative asset as hedging instrument offset		0.0
Derivative Asset	5.0	13.0
Prepayments And Other [Member] | Fixed Transmission Rights (FTRs) [Member] | Utility and Entergy Wholesale Commodities [Member] | Not Designated As Hedging Instrument [Member]
Assets:
Derivative Asset, Fair Value, Gross Asset	9.0	22.0
Derivative asset as hedging instrument offset	(1.0)	(1.0)
Derivative Asset	8.0	21.0
Other Current Liabilities [Member] | Electricity Swaps And Options [Member] | Entergy Wholesale Commodities [Member] | Designated As Hedging Instrument [Member]
Liabilities:
Derivative liability as hedging instrument offset	(14.0)	(10.0)
Derivative Liability, Fair Value, Gross Liability	24.0	11.0
Derivative Liability	10.0	1.0
Other Current Liabilities [Member] | Electricity Swaps And Options [Member] | Entergy Wholesale Commodities [Member] | Not Designated As Hedging Instrument [Member]
Liabilities:
Derivative liability as hedging instrument offset	(4.0)	(17.0)
Derivative Liability, Fair Value, Gross Liability	8.0	18.0
Derivative Liability	4.0	1.0
Entergy Louisiana [Member] | Prepayments And Other [Member] | Natural Gas Swaps [Member] | Not Designated As Hedging Instrument [Member]
Assets:
Derivative Asset	3.8	10.9
Entergy Louisiana [Member] | Prepayments And Other [Member] | Fixed Transmission Rights (FTRs) [Member] | Not Designated As Hedging Instrument [Member]
Assets:
Derivative Asset	4.1	8.5
Entergy Mississippi [Member] | Prepayments And Other [Member] | Natural Gas Swaps [Member] | Not Designated As Hedging Instrument [Member]
Assets:
Derivative Asset	0.7	2.3
Entergy Mississippi [Member] | Prepayments And Other [Member] | Fixed Transmission Rights (FTRs) [Member] | Not Designated As Hedging Instrument [Member]
Assets:
Derivative Asset	1.3	3.2
Entergy New Orleans [Member] | Prepayments And Other [Member] | Natural Gas Swaps [Member] | Not Designated As Hedging Instrument [Member]
Assets:
Derivative Asset		0.2
Entergy New Orleans [Member] | Prepayments And Other [Member] | Fixed Transmission Rights (FTRs) [Member] | Not Designated As Hedging Instrument [Member]
Assets:
Derivative Asset	0.5	1.1
Entergy Arkansas [Member] | Prepayments And Other [Member] | Fixed Transmission Rights (FTRs) [Member] | Not Designated As Hedging Instrument [Member]
Assets:
Derivative Asset	0.9	5.4
Entergy Texas [Member] | Prepayments And Other [Member] | Fixed Transmission Rights (FTRs) [Member] | Not Designated As Hedging Instrument [Member]
Assets:
Derivative Asset	$ 1.0	$ 3.1