Risk Management and Fair Values (Derivative Instruments Not Designated As Hedging Instruments On The Consolidated Statements Of Income) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Competitive Businesses Operating Revenues [Member] | Electricity Swaps And Options [Member] | Not Designated As Hedging Instrument [Member]
Effect Of Derivative Instruments Not Designated As Hedging Instruments On The Consolidated Statements Of Income [Line Items]
Derivative, Gain (Loss) on Derivative, Net	$ 2.0	$ 1.0	$ 0.0	$ 4.0
Fuel, Fuel Related Expenses And Gas Purchased For Resale [Member] | Natural Gas Swaps [Member] | Not Designated As Hedging Instrument [Member]
Effect Of Derivative Instruments Not Designated As Hedging Instruments On The Consolidated Statements Of Income [Line Items]
Derivative, Gain (Loss) on Derivative, Net	(1.0)	(2.0)	(3.0)	(9.0)
Purchased Power Expense [Member] | Fixed Transmission Rights (FTRs) [Member] | Not Designated As Hedging Instrument [Member]
Effect Of Derivative Instruments Not Designated As Hedging Instruments On The Consolidated Statements Of Income [Line Items]
Derivative, Gain (Loss) on Derivative, Net	33.0	25.0	61.0	78.0
Entergy Arkansas [Member]
Effect Of Derivative Instruments Not Designated As Hedging Instruments On The Consolidated Statements Of Income [Line Items]
Letters of Credit Outstanding, Amount	1.9		1.9
Entergy Arkansas [Member] | Purchased Power Expense [Member] | Fixed Transmission Rights (FTRs) [Member] | Not Designated As Hedging Instrument [Member]
Effect Of Derivative Instruments Not Designated As Hedging Instruments On The Consolidated Statements Of Income [Line Items]
Derivative, Gain (Loss) on Derivative, Net	5.2	3.5	14.7	15.4
Entergy Louisiana [Member]
Effect Of Derivative Instruments Not Designated As Hedging Instruments On The Consolidated Statements Of Income [Line Items]
Letters of Credit Outstanding, Amount	2.2		2.2
Entergy Louisiana [Member] | Natural Gas Swaps [Member] | Not Designated As Hedging Instrument [Member] | Other Current Liabilities [Member]
Effect Of Derivative Instruments Not Designated As Hedging Instruments On The Consolidated Statements Of Income [Line Items]
Derivative Liability, Fair Value, Gross Liability					$ 2.4
Derivative, Collateral, Right to Reclaim Cash					0.0
Derivative Liability					2.4
Entergy Louisiana [Member] | Natural Gas Swaps [Member] | Not Designated As Hedging Instrument [Member] | Other Noncurrent Liabilities
Effect Of Derivative Instruments Not Designated As Hedging Instruments On The Consolidated Statements Of Income [Line Items]
Derivative Liability, Fair Value, Gross Liability					2.2
Derivative, Collateral, Right to Reclaim Cash					0.0
Derivative Liability					2.2
Entergy Louisiana [Member] | Fuel, Fuel Related Expenses And Gas Purchased For Resale [Member] | Natural Gas Swaps [Member] | Not Designated As Hedging Instrument [Member]
Effect Of Derivative Instruments Not Designated As Hedging Instruments On The Consolidated Statements Of Income [Line Items]
Derivative, Gain (Loss) on Derivative, Net	1.4	(1.7)	1.4	(3.6)
Entergy Louisiana [Member] | Purchased Power Expense [Member] | Fixed Transmission Rights (FTRs) [Member] | Not Designated As Hedging Instrument [Member]
Effect Of Derivative Instruments Not Designated As Hedging Instruments On The Consolidated Statements Of Income [Line Items]
Derivative, Gain (Loss) on Derivative, Net	3.1	14.4	13.9	40.9
Entergy Mississippi [Member]
Effect Of Derivative Instruments Not Designated As Hedging Instruments On The Consolidated Statements Of Income [Line Items]
Letters of Credit Outstanding, Amount	0.7		0.7		0.2
Entergy Mississippi [Member] | Natural Gas Swaps [Member] | Not Designated As Hedging Instrument [Member] | Other Current Liabilities [Member]
Effect Of Derivative Instruments Not Designated As Hedging Instruments On The Consolidated Statements Of Income [Line Items]
Derivative Liability, Fair Value, Gross Liability					2.3
Derivative, Collateral, Right to Reclaim Cash					0.0
Derivative Liability					2.3
Entergy Mississippi [Member] | Fuel, Fuel Related Expenses And Gas Purchased For Resale [Member] | Natural Gas Swaps [Member] | Not Designated As Hedging Instrument [Member]
Effect Of Derivative Instruments Not Designated As Hedging Instruments On The Consolidated Statements Of Income [Line Items]
Derivative, Gain (Loss) on Derivative, Net	(1.5)	(0.3)	(4.0)	(5.5)
Entergy Mississippi [Member] | Purchased Power Expense [Member] | Fixed Transmission Rights (FTRs) [Member] | Not Designated As Hedging Instrument [Member]
Effect Of Derivative Instruments Not Designated As Hedging Instruments On The Consolidated Statements Of Income [Line Items]
Derivative, Gain (Loss) on Derivative, Net	1.3	1.9	0.7	5.3
Entergy New Orleans [Member]
Effect Of Derivative Instruments Not Designated As Hedging Instruments On The Consolidated Statements Of Income [Line Items]
Letters of Credit Outstanding, Amount	0.2		0.2
Entergy New Orleans [Member] | Natural Gas Swaps [Member] | Not Designated As Hedging Instrument [Member] | Other Current Liabilities [Member]
Effect Of Derivative Instruments Not Designated As Hedging Instruments On The Consolidated Statements Of Income [Line Items]
Derivative Liability, Fair Value, Gross Liability					0.2
Derivative, Collateral, Right to Reclaim Cash					0.0
Derivative Liability					$ 0.2
Entergy New Orleans [Member] | Fuel, Fuel Related Expenses And Gas Purchased For Resale [Member] | Natural Gas Swaps [Member] | Not Designated As Hedging Instrument [Member]
Effect Of Derivative Instruments Not Designated As Hedging Instruments On The Consolidated Statements Of Income [Line Items]
Derivative, Gain (Loss) on Derivative, Net	(0.5)	(0.1)	(0.5)	0.1
Entergy New Orleans [Member] | Purchased Power Expense [Member] | Fixed Transmission Rights (FTRs) [Member] | Not Designated As Hedging Instrument [Member]
Effect Of Derivative Instruments Not Designated As Hedging Instruments On The Consolidated Statements Of Income [Line Items]
Derivative, Gain (Loss) on Derivative, Net	0.1	(0.3)	0.8	2.2
Entergy Texas [Member] | Purchased Power Expense [Member] | Fixed Transmission Rights (FTRs) [Member] | Not Designated As Hedging Instrument [Member]
Effect Of Derivative Instruments Not Designated As Hedging Instruments On The Consolidated Statements Of Income [Line Items]
Derivative, Gain (Loss) on Derivative, Net	$ 22.8	$ 5.5	$ 30.5	$ 13.6