Risk Management and Fair Values (Narrative) (Details) TWh in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Mar. 31, 2020 USD ($) GWh MMBTU	Mar. 31, 2019 USD ($)	Dec. 31, 2020 TWh	Dec. 31, 2019 USD ($)
Debt Securities, Available-for-sale, Allowance for Credit Loss	$ 3.0
Risk Management and Fair Values [Abstract]
Letters of Credit Outstanding, Amount	6.0
Derivative, Collateral, Obligation to Return Cash				$ 1.0
Cash flow hedges relating to power sales as part of net unrealized gains	81.0
Reclassified from accumulated other comprehensive income (OCI) to operating revenues	80.0
Maturity of cash flow hedges, Tax	$ 20.0	$ 11.0
Maximum length of time over which Company is currently hedging the variability in future cash flows for forecasted power transactions, years	1 year
Total volume of natural gas swaps outstanding (MMBtu) | MMBTU	42,371,000
Total volume of fixed transmission rights outstanding | GWh	18,987
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset and Liability Unrealized Gains (Loss) Included in Earnings	$ 1.0	$ (4.9)
Entergy Arkansas [Member]
Risk Management and Fair Values [Abstract]
Total volume of fixed transmission rights outstanding | GWh	4,368
Entergy Louisiana [Member]
Risk Management and Fair Values [Abstract]
Total volume of natural gas swaps outstanding (MMBtu) | MMBTU	29,220,000
Total volume of fixed transmission rights outstanding | GWh	8,517
Entergy Mississippi [Member]
Risk Management and Fair Values [Abstract]
Letters of Credit Outstanding, Amount	$ 0.2			0.2
Total volume of natural gas swaps outstanding (MMBtu) | MMBTU	13,151,000
Total volume of fixed transmission rights outstanding | GWh	2,427
Entergy New Orleans [Member]
Risk Management and Fair Values [Abstract]
Total volume of fixed transmission rights outstanding | GWh	934
Entergy Texas [Member]
Risk Management and Fair Values [Abstract]
Total volume of fixed transmission rights outstanding | GWh	2,662
Gas Hedge Contracts [Member] | Entergy Louisiana [Member]
Risk Management and Fair Values [Abstract]
Maximum Length of Time Hedged in Cash Flow Hedge	4 years
Gas Hedge Contracts [Member] | Entergy Mississippi [Member]
Risk Management and Fair Values [Abstract]
Maximum Length of Time Hedged in Cash Flow Hedge	7 months
Entergy Wholesale Commodities [Member]
Risk Management and Fair Values [Abstract]
Cash collateral posted	$ 9.0			11.0
Derivative, Collateral, Obligation to Return Cash				1.0
Letters of Credit Held	$ 95.0			$ 98.0
Subsequent Event [Member]
Risk Management and Fair Values [Abstract]
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			61.00%
Total planned generation for remainder of the period | TWh			11.6