Risk Management and Fair Values (Fair Values Of Derivative Instruments) (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Prepayments And Other [Member] | Electricity Futures Forwards Swaps And Options [Member] | Entergy Wholesale Commodities [Member] | Designated as Hedging Instrument [Member]
Assets:
Derivative asset, fair value	$ 92.0	$ 32.0
Derivative asset as hedging instrument offset	(1.0)	(32.0)
Derivative Asset	91.0	0.0
Prepayments And Other [Member] | Electricity Futures Forwards Swaps And Options [Member] | Entergy Wholesale Commodities [Member] | Not Designated As Hedging Instrument [Member]
Assets:
Derivative asset, fair value	11.0	4.0
Derivative asset as hedging instrument offset	(1.0)	(2.0)
Derivative Asset	10.0	2.0
Prepayments And Other [Member] | Financial Transmission Rights (FTRs) [Member] | Utility and Entergy Wholesale Commodities [Member] | Not Designated As Hedging Instrument [Member]
Assets:
Derivative asset, fair value	10.0	16.0
Derivative asset as hedging instrument offset		(1.0)
Derivative Asset	10.0	15.0
Other Deferred Debits And Other Assets [Member] | Electricity Futures Forwards Swaps And Options [Member] | Entergy Wholesale Commodities [Member] | Designated as Hedging Instrument [Member]
Assets:
Derivative asset, fair value	17.0	7.0
Derivative asset as hedging instrument offset	0.0	(7.0)
Derivative Asset	17.0	0.0
Other Deferred Debits And Other Assets [Member] | Electricity Futures Forwards Swaps And Options [Member] | Entergy Wholesale Commodities [Member] | Not Designated As Hedging Instrument [Member]
Assets:
Derivative asset, fair value		1.0
Derivative asset as hedging instrument offset		0.0
Derivative Asset		1.0
Other Deferred Debits And Other Assets [Member] | Natural Gas Swaps [Member] | Utility [Member] | Not Designated As Hedging Instrument [Member]
Assets:
Derivative asset, fair value	1.0	2.0
Derivative asset as hedging instrument offset		0.0
Derivative Asset	1.0	2.0
Other Non-Current Liabilities [Member] | Electricity Futures Forwards Swaps And Options [Member] | Entergy Wholesale Commodities [Member] | Designated as Hedging Instrument [Member]
Liabilities:
Derivative Liability, Fair Value, Gross Liability		20.0
Derivative liability as hedging instrument offset		(7.0)
Derivative Liability		13.0
Derivative Liability, Fair Value, Gross Liability		20.0
Other Non-Current Liabilities [Member] | Natural Gas Swaps [Member] | Utility [Member] | Not Designated As Hedging Instrument [Member]
Liabilities:
Derivative Liability, Fair Value, Gross Liability	2.0
Derivative liability as hedging instrument offset	0.0
Derivative Liability	2.0
Derivative Liability, Fair Value, Gross Liability	2.0
Other Current Liabilities [Member] | Electricity Futures Forwards Swaps And Options [Member] | Entergy Wholesale Commodities [Member] | Designated as Hedging Instrument [Member]
Liabilities:
Derivative Liability, Fair Value, Gross Liability	1.0	54.0
Derivative liability as hedging instrument offset	(1.0)	(33.0)
Derivative Liability	0.0	21.0
Derivative Liability, Fair Value, Gross Liability	1.0	54.0
Other Current Liabilities [Member] | Electricity Futures Forwards Swaps And Options [Member] | Entergy Wholesale Commodities [Member] | Not Designated As Hedging Instrument [Member]
Liabilities:
Derivative Liability, Fair Value, Gross Liability	2.0	1.0
Derivative liability as hedging instrument offset	(2.0)	(1.0)
Derivative Liability	0.0	0.0
Derivative Liability, Fair Value, Gross Liability	2.0	1.0
Other Current Liabilities [Member] | Natural Gas Swaps [Member] | Utility [Member] | Not Designated As Hedging Instrument [Member]
Liabilities:
Derivative Liability, Fair Value, Gross Liability	5.0	1.0
Derivative liability as hedging instrument offset	0.0
Derivative Liability	5.0	1.0
Derivative Liability, Fair Value, Gross Liability	5.0	1.0
Entergy Louisiana [Member] | Prepayments And Other [Member] | Natural Gas Swaps [Member] | Not Designated As Hedging Instrument [Member]
Assets:
Derivative asset, fair value		0.3
Derivative asset as hedging instrument offset		0.0
Derivative Asset		0.3
Entergy Louisiana [Member] | Prepayments And Other [Member] | Financial Transmission Rights (FTRs) [Member] | Not Designated As Hedging Instrument [Member]
Assets:
Derivative asset, fair value	4.5	8.4
Derivative asset as hedging instrument offset	0.0	0.1
Derivative Asset	4.5	8.3
Entergy Louisiana [Member] | Other Deferred Debits And Other Assets [Member] | Natural Gas Swaps [Member] | Not Designated As Hedging Instrument [Member]
Assets:
Derivative asset, fair value	0.8	1.6
Derivative asset as hedging instrument offset	0.0	0.0
Derivative Asset	0.8	1.6
Entergy Louisiana [Member] | Other Non-Current Liabilities [Member] | Natural Gas Swaps [Member] | Not Designated As Hedging Instrument [Member]
Liabilities:
Derivative Liability, Fair Value, Gross Liability	2.2
Derivative liability as hedging instrument offset	0.0
Derivative Liability	2.2
Derivative Liability, Fair Value, Gross Liability	2.2
Entergy Louisiana [Member] | Other Current Liabilities [Member] | Natural Gas Swaps [Member] | Not Designated As Hedging Instrument [Member]
Liabilities:
Derivative Liability, Fair Value, Gross Liability	2.4	1.1
Derivative liability as hedging instrument offset	0.0	0.0
Derivative Liability	2.4	1.1
Derivative Liability, Fair Value, Gross Liability	2.4	1.1
Entergy Arkansas [Member] | Prepayments And Other [Member] | Financial Transmission Rights (FTRs) [Member] | Not Designated As Hedging Instrument [Member]
Assets:
Derivative asset, fair value	3.4	3.6
Derivative asset as hedging instrument offset	0.1	0.2
Derivative Asset	3.3	3.4
Entergy Mississippi [Member] | Prepayments And Other [Member] | Financial Transmission Rights (FTRs) [Member] | Not Designated As Hedging Instrument [Member]
Assets:
Derivative asset, fair value	0.8	2.2
Derivative asset as hedging instrument offset	0.0	0.0
Derivative Asset	0.8	2.2
Entergy Mississippi [Member] | Other Current Liabilities [Member] | Natural Gas Swaps [Member] | Not Designated As Hedging Instrument [Member]
Liabilities:
Derivative Liability, Fair Value, Gross Liability	2.3
Derivative liability as hedging instrument offset	0.0
Derivative Liability	2.3
Derivative Liability, Fair Value, Gross Liability	2.3
Entergy New Orleans [Member] | Prepayments And Other [Member] | Financial Transmission Rights (FTRs) [Member] | Not Designated As Hedging Instrument [Member]
Assets:
Derivative asset, fair value	0.3	1.3
Derivative asset as hedging instrument offset	0.0	0.0
Derivative Asset	0.3	1.3
Entergy New Orleans [Member] | Other Current Liabilities [Member] | Natural Gas Swaps [Member] | Not Designated As Hedging Instrument [Member]
Liabilities:
Derivative Liability, Fair Value, Gross Liability	0.2	0.1
Derivative liability as hedging instrument offset	0.0	0.0
Derivative Liability	0.2	0.1
Derivative Liability, Fair Value, Gross Liability	0.2	0.1
Entergy Texas [Member] | Prepayments And Other [Member] | Financial Transmission Rights (FTRs) [Member] | Not Designated As Hedging Instrument [Member]
Assets:
Derivative asset, fair value	1.0
Derivative asset as hedging instrument offset	0.1
Derivative Asset	$ 0.9
Entergy Texas [Member] | Other Current Liabilities [Member] | Financial Transmission Rights (FTRs) [Member] | Not Designated As Hedging Instrument [Member]
Assets:
Derivative asset, fair value		0.9
Derivative asset as hedging instrument offset		1.4
Liabilities:
Derivative Liability		$ (0.5)