Risk Management and Fair Values Fair Values Of Derivative Instruments (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
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	$ 39.0	$ 92.0
Derivative asset as hedging instrument offset	(1.0)	(1.0)
Derivative Asset	38.0	91.0
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
Derivative asset as hedging instrument offset		(1.0)
Derivative Asset		10.0
Prepayments And Other [Member] | Natural Gas Swaps [Member] | Utility [Member] | Not Designated As Hedging Instrument [Member]
Assets:
Derivative asset, fair value	1.0
Derivative Asset	1.0
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	9.0	10.0
Derivative asset as hedging instrument offset		0.0
Derivative Asset	9.0	10.0
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
Derivative asset as hedging instrument offset		0.0
Derivative Asset		17.0
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	1.0
Derivative asset as hedging instrument offset		0.0
Derivative Asset	1.0	1.0
Other Non-Current Liabilities [Member] | Natural Gas Swaps [Member] | Utility [Member] | Not Designated As Hedging Instrument [Member]
Liabilities:
Derivative Liability, Fair Value, Gross Liability	1.0	2.0
Derivative liability as hedging instrument offset	0.0
Derivative Liability	1.0	2.0
Derivative Liability, Fair Value, Gross Liability	1.0	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	1.0
Derivative liability as hedging instrument offset	(1.0)	(1.0)
Derivative Liability	0.0	0.0
Derivative Liability, Fair Value, Gross Liability	1.0	1.0
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
Derivative liability as hedging instrument offset		(2.0)
Derivative Liability		0.0
Derivative Liability, Fair Value, Gross Liability		2.0
Other Current Liabilities [Member] | Natural Gas Swaps [Member] | Utility [Member] | Not Designated As Hedging Instrument [Member]
Liabilities:
Derivative Liability, Fair Value, Gross Liability	6.0	5.0
Derivative liability as hedging instrument offset	0.0
Derivative Liability	6.0	5.0
Derivative Liability, Fair Value, Gross Liability	6.0	5.0
Entergy Louisiana [Member] | Prepayments And Other [Member] | Natural Gas Swaps [Member] | Not Designated As Hedging Instrument [Member]
Assets:
Derivative asset, fair value	0.8
Derivative asset as hedging instrument offset	0.0
Derivative Asset	0.8
Entergy Louisiana [Member] | Prepayments And Other [Member] | Financial Transmission Rights (FTRs) [Member] | Not Designated As Hedging Instrument [Member]
Assets:
Derivative asset, fair value	4.3	4.5
Derivative asset as hedging instrument offset	0.1	0.0
Derivative Asset	4.2	4.5
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	0.5	0.8
Derivative asset as hedging instrument offset	0.0	0.0
Derivative Asset	0.5	0.8
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	1.3	2.2
Derivative liability as hedging instrument offset	0.0	0.0
Derivative Liability	1.3	2.2
Derivative Liability, Fair Value, Gross Liability	1.3	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	0.3	2.4
Derivative liability as hedging instrument offset	0.0	0.0
Derivative Liability	0.3	2.4
Derivative Liability, Fair Value, Gross Liability	0.3	2.4
Entergy Arkansas [Member] | Prepayments And Other [Member] | Financial Transmission Rights (FTRs) [Member] | Not Designated As Hedging Instrument [Member]
Assets:
Derivative asset, fair value	2.9	3.4
Derivative asset as hedging instrument offset	0.2	0.1
Derivative Asset	2.7	3.3
Entergy Mississippi [Member] | Prepayments And Other [Member] | Financial Transmission Rights (FTRs) [Member] | Not Designated As Hedging Instrument [Member]
Assets:
Derivative asset, fair value	0.6	0.8
Derivative asset as hedging instrument offset	0.0	0.0
Derivative Asset	0.6	0.8
Entergy Mississippi [Member] | Other Current Liabilities [Member] | Natural Gas Swaps [Member] | Not Designated As Hedging Instrument [Member]
Liabilities:
Derivative Liability, Fair Value, Gross Liability	5.0	2.3
Derivative liability as hedging instrument offset	0.0	0.0
Derivative Liability	5.0	2.3
Derivative Liability, Fair Value, Gross Liability	5.0	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	0.2	0.3
Derivative asset as hedging instrument offset	0.1	0.0
Derivative Asset	0.1	0.3
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	0.3	0.2
Derivative liability as hedging instrument offset	0.0	0.0
Derivative Liability	0.3	0.2
Derivative Liability, Fair Value, Gross Liability	0.3	0.2
Entergy Texas [Member] | Prepayments And Other [Member] | Financial Transmission Rights (FTRs) [Member] | Not Designated As Hedging Instrument [Member]
Assets:
Derivative asset, fair value	1.6	1.0
Derivative asset as hedging instrument offset	0.0	0.1
Derivative Asset	$ 1.6	$ 0.9