Risk Management and Fair Values (Narrative) (Details) TWh in Millions, $ in Millions	3 Months Ended			9 Months Ended
	Dec. 31, 2020 TWh	Sep. 30, 2020 USD ($) MMBTU GWh	Sep. 30, 2019 USD ($)	Sep. 30, 2020 USD ($) MMBTU GWh	Sep. 30, 2019 USD ($)	Dec. 31, 2019 USD ($)
Cash flow hedges relating to power sales as part of net unrealized gains				$ 27.0
Reclassified from accumulated other comprehensive income (OCI) to operating revenues				27.0
Maturity of cash flow hedges, Tax		$ 3.0	$ 4.0	$ 28.0	$ 16.0
Maximum length of time over which Company is currently hedging the variability in future cash flows for forecasted power transactions, years				6 months
Total volume of natural gas swaps outstanding (MMBtu) | MMBTU		38,070,000		38,070,000
Total volume of fixed transmission rights outstanding | GWh		92,491		92,491
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset and Liability Unrealized Gains (Loss) Included in Earnings		$ (3.7)	$ (1.2)	$ (0.2)	$ (4.7)
Debt Securities, Available-for-sale, Allowance for Credit Loss		0.6		0.6
Letters Of Credit		6.0		6.0
Entergy Arkansas [Member]
Letters of Credit Outstanding, Amount		$ 1.9		$ 1.9
Total volume of fixed transmission rights outstanding | GWh		22,239		22,239
Entergy Louisiana [Member]
Letters of Credit Outstanding, Amount		$ 2.2		$ 2.2
Total volume of natural gas swaps outstanding (MMBtu) | MMBTU		25,560,000		25,560,000
Total volume of fixed transmission rights outstanding | GWh		43,454		43,454
Entergy Mississippi [Member]
Letters of Credit Outstanding, Amount		$ 0.7		$ 0.7		$ 0.2
Total volume of natural gas swaps outstanding (MMBtu) | MMBTU		11,506,000		11,506,000
Total volume of fixed transmission rights outstanding | GWh		10,353		10,353
Entergy New Orleans [Member]
Letters of Credit Outstanding, Amount		$ 0.2		$ 0.2
Total volume of natural gas swaps outstanding (MMBtu) | MMBTU		1,004,000		1,004,000
Total volume of fixed transmission rights outstanding | GWh		4,243		4,243
Entergy Texas [Member]
Total volume of fixed transmission rights outstanding | GWh		11,889		11,889
Entergy Wholesale Commodities [Member]
Derivative, Collateral, Obligation to Return Cash						1.0
Letters of Credit Held						98.0
Gas Hedge Contracts [Member] | Entergy Louisiana [Member]
Maximum Length of Time Hedged in Cash Flow Hedge				3 years 6 months
Gas Hedge Contracts [Member] | Entergy Mississippi [Member]
Maximum Length of Time Hedged in Cash Flow Hedge				6 months
Gas Hedge Contracts [Member] | Entergy New Orleans [Member]
Maximum Length of Time Hedged in Cash Flow Hedge				6 months
Entergy Wholesale Commodities [Member]
Cash collateral posted		$ 1.0		$ 1.0		11.0
Letters of Credit Held		22.0		22.0		98.0
Collateral Held						$ 1.0
Letters Of Credit		$ 5.0		$ 5.0
Subsequent Event [Member]
Planned generation sold forward from non utility nuclear power plants for the remainder of the period	97.00%
Planned Generation From Non Nuclear Power Plants Sold Forward Under Financial Hedges	62.00%
Total planned generation for remainder of the period | TWh	3.5