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, 2019	Dec. 31, 2018	Dec. 31, 2017
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	$ (13.0)	$ 8.0	$ (31.0)
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	94.0	131.0	139.0
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	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	(25.4)
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	46.7	72.7	45.8
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	(7.7)	3.2	(5.2)
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	6.8	26.3	18.9
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		0.2	(0.3)
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	2.7	13.8	9.1
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	22.3	25.3	41.7
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	$ 15.7	$ (6.0)	$ 22.3