Risk Management and Fair Values (Fair Values Of Derivative Instruments) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Assets:
Derivative asset as hedging instrument offset		$ (68.0)
Liabilities:
Cash collateral posted	$ 2.0	9.0
Prepayments And Other [Member] | Electricity Swaps And Options [Member] | Entergy Wholesale Commodities [Member] | Designated as Hedging Instrument [Member]
Assets:
Derivative asset, fair value	25.0	173.0
Derivative asset as hedging instrument offset	(14.0)	(34.0)
Derivative asset, net	11.0	139.0
Prepayments And Other [Member] | Electricity Swaps And Options [Member] | Entergy Wholesale Commodities [Member] | Not Designated As Hedging Instrument [Member]
Assets:
Derivative asset, fair value	18.0	54.0
Derivative asset as hedging instrument offset	(13.0)	(13.0)
Derivative asset, net	5.0	41.0
Prepayments And Other [Member] | Natural Gas Swaps [Member] | Utility Plants [Member] | Not Designated As Hedging Instrument [Member]
Assets:
Derivative asset, fair value	13.0
Derivative asset, net	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	22.0	24.0
Derivative asset as hedging instrument offset	(1.0)	(1.0)
Derivative asset, net	21.0	23.0
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	6.0	17.0
Derivative asset as hedging instrument offset	(6.0)	(2.0)
Derivative asset, net	0.0	15.0
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	5.0
Derivative asset as hedging instrument offset	(5.0)
Derivative asset, net	0.0
Other Non-Current Liabilities [Member] | Electricity Swaps And Options [Member] | Entergy Wholesale Commodities [Member] | Designated as Hedging Instrument [Member]
Liabilities:
Derivative Liability, Fair Value, Gross Liability	16.0	2.0
Derivative liability as hedging instrument offset	(7.0)	(2.0)
Derivative liability, net	9.0	0.0
Derivative Liability, Fair Value, Gross Liability	16.0	2.0
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, Gross Liability	4.0
Derivative liability as hedging instrument offset	(4.0)
Derivative liability, net	0.0
Derivative Liability, Fair Value, Gross Liability	4.0
Other Current Liabilities [Member] | Electricity Swaps And Options [Member] | Entergy Wholesale Commodities [Member] | Designated as Hedging Instrument [Member]
Liabilities:
Derivative Liability, Fair Value, Gross Liability	11.0	14.0
Derivative liability as hedging instrument offset	(10.0)	(14.0)
Derivative liability, net	1.0	0.0
Derivative Liability, Fair Value, Gross Liability	11.0	14.0
Other Current Liabilities [Member] | Electricity Swaps And Options [Member] | Entergy Wholesale Commodities [Member] | Not Designated As Hedging Instrument [Member]
Liabilities:
Derivative Liability, Fair Value, Gross Liability	18.0	38.0
Derivative liability as hedging instrument offset	(17.0)	(32.0)
Derivative liability, net	1.0	6.0
Derivative Liability, Fair Value, Gross Liability	18.0	38.0
Other Current Liabilities [Member] | Natural Gas Swaps [Member] | Utility Plants [Member] | Not Designated As Hedging Instrument [Member]
Liabilities:
Derivative Liability, Fair Value, Gross Liability		9.0
Derivative liability, net		9.0
Derivative Liability, Fair Value, Gross Liability		9.0
Entergy Louisiana [Member] | Prepayments And Other [Member] | Natural Gas Swaps [Member] | Not Designated As Hedging Instrument [Member]
Assets:
Derivative asset, net	10.9
Entergy Louisiana [Member] | Prepayments And Other [Member] | Fixed Transmission Rights (FTRs) [Member] | Not Designated As Hedging Instrument [Member]
Assets:
Derivative asset, net	8.5	8.5
Entergy Louisiana [Member] | Other Current Liabilities [Member] | Natural Gas Swaps [Member] | Not Designated As Hedging Instrument [Member]
Liabilities:
Derivative liability, net		7.0
Entergy Mississippi [Member] | Prepayments And Other [Member] | Natural Gas Swaps [Member] | Not Designated As Hedging Instrument [Member]
Assets:
Derivative asset, net	2.3
Entergy Mississippi [Member] | Prepayments And Other [Member] | Fixed Transmission Rights (FTRs) [Member] | Not Designated As Hedging Instrument [Member]
Assets:
Derivative asset, net	3.2	2.4
Entergy Mississippi [Member] | Other Current Liabilities [Member] | Natural Gas Swaps [Member] | Not Designated As Hedging Instrument [Member]
Liabilities:
Derivative liability, net		1.3
Entergy New Orleans [Member] | Prepayments And Other [Member] | Natural Gas Swaps [Member] | Not Designated As Hedging Instrument [Member]
Assets:
Derivative asset, net	0.2
Entergy New Orleans [Member] | Prepayments And Other [Member] | Fixed Transmission Rights (FTRs) [Member] | Not Designated As Hedging Instrument [Member]
Assets:
Derivative asset, net	1.1	1.5
Entergy New Orleans [Member] | Other Current Liabilities [Member] | Natural Gas Swaps [Member] | Not Designated As Hedging Instrument [Member]
Liabilities:
Derivative liability, net		0.5
Entergy Texas [Member] | Prepayments And Other [Member] | Fixed Transmission Rights (FTRs) [Member] | Not Designated As Hedging Instrument [Member]
Assets:
Derivative asset, net	3.1	2.2
Entergy Arkansas [Member] | Prepayments And Other [Member] | Fixed Transmission Rights (FTRs) [Member] | Not Designated As Hedging Instrument [Member]
Assets:
Derivative asset, net	$ 5.4	$ 7.9