Risk Management and Fair Values Derivative Instruments Not Designated As Hedging Instruments On The Consolidated Statements Of Income (Details) - Not Designated As Hedging Instrument [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Fuel, Fuel Related Expenses And Gas Purchased For Resale [Member] | Natural Gas Swaps [Member]
Effect of Derivative instruments not designated as hedging instruments on the consolidated statements of income
Amount of gain (loss) recorded in income	$ (12.0)	$ (13.0)	$ 8.0
Purchased Power Expense [Member] | Financial Transmission Rights (FTRs) [Member]
Effect of Derivative instruments not designated as hedging instruments on the consolidated statements of income
Amount of gain (loss) recorded in income	92.0	94.0	131.0
Competitive Businesses Operating Revenues [Member] | Electricity Futures Forwards Swaps And Options [Member]
Effect of Derivative instruments not designated as hedging instruments on the consolidated statements of income
Amount of gain (loss) recorded in income	1.0	12.0	8.0
Entergy Louisiana [Member] | Fuel, Fuel Related Expenses And Gas Purchased For Resale [Member] | Natural Gas Swaps [Member]
Effect of Derivative instruments not designated as hedging instruments on the consolidated statements of income
Amount of gain (loss) recorded in income		(5.3)	4.4
Entergy Louisiana [Member] | Purchased Power Expense [Member] | Financial Transmission Rights (FTRs) [Member]
Effect of Derivative instruments not designated as hedging instruments on the consolidated statements of income
Amount of gain (loss) recorded in income	19.6	46.7	72.7
Entergy Mississippi [Member] | Fuel, Fuel Related Expenses And Gas Purchased For Resale [Member] | Natural Gas Swaps [Member]
Effect of Derivative instruments not designated as hedging instruments on the consolidated statements of income
Amount of gain (loss) recorded in income	(11.1)	(7.7)	3.2
Entergy Mississippi [Member] | Purchased Power Expense [Member] | Financial Transmission Rights (FTRs) [Member]
Effect of Derivative instruments not designated as hedging instruments on the consolidated statements of income
Amount of gain (loss) recorded in income	3.0	6.8	26.3
Entergy New Orleans [Member] | Fuel, Fuel Related Expenses And Gas Purchased For Resale [Member] | Natural Gas Swaps [Member]
Effect of Derivative instruments not designated as hedging instruments on the consolidated statements of income
Amount of gain (loss) recorded in income	(0.8)		0.2
Entergy New Orleans [Member] | Purchased Power Expense [Member] | Financial Transmission Rights (FTRs) [Member]
Effect of Derivative instruments not designated as hedging instruments on the consolidated statements of income
Amount of gain (loss) recorded in income	1.4	2.7	13.8
Entergy Arkansas [Member] | Purchased Power Expense [Member] | Financial Transmission Rights (FTRs) [Member]
Effect of Derivative instruments not designated as hedging instruments on the consolidated statements of income
Amount of gain (loss) recorded in income	26.7	22.3	25.3
Entergy Texas [Member] | Purchased Power Expense [Member] | Financial Transmission Rights (FTRs) [Member]
Effect of Derivative instruments not designated as hedging instruments on the consolidated statements of income
Amount of gain (loss) recorded in income	$ 40.4	$ 15.7	$ (6.0)