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		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 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)	$ (2.0)	$ (2.0)	$ 3.0
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	(3.0)	(6.0)	(9.0)	(7.0)
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	15.0	32.0	28.0	53.0
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	3.1		3.1
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	4.8	3.6	9.4	12.0
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	2.3		2.3
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	1.7		1.7		$ 2.4
Derivative, Collateral, Right to Reclaim Cash	0.0		0.0		0.0
Derivative Liability	1.7		1.7		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		(2.7)	(1.3)	(1.9)
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	5.4	17.7	10.7	26.5
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	1.5		1.5		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	4.3		4.3		2.3
Derivative, Collateral, Right to Reclaim Cash	0.0		0.0		0.0
Derivative Liability	4.3		4.3		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	(2.5)	(3.5)	(7.7)	(5.2)
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	(0.4)	2.2	(0.5)	3.3
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	0.5		0.5
Entergy New Orleans [Member] | Fixed Transmission Rights (FTRs) [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	0.3		0.3
Derivative, Collateral, Right to Reclaim Cash	0.5		0.5
Derivative Liability	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			(0.4)	0.2
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	0.2	0.7	0.6	2.6
Entergy Texas [Member]
Effect Of Derivative Instruments Not Designated As Hedging Instruments On The Consolidated Statements Of Income [Line Items]
Letters of Credit Outstanding, Amount	0.4		0.4
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	$ 5.3	$ 7.8	$ 7.6	$ 8.1