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, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
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	$ 0.0	$ (2.0)	$ (2.0)	$ (2.0)
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	18.0	(3.0)	25.0	(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	16.0	15.0	144.0	28.0
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	1.5		1.5
Entergy Arkansas [Member] | Fixed Transmission Rights (FTRs) [Member] | Not Designated As Hedging Instrument [Member] | Prepayments And Other [Member]
Effect Of Derivative Instruments Not Designated As Hedging Instruments On The Consolidated Statements Of Income [Line Items]
Derivative Asset	3.8		3.8		$ 2.7
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	3.4	4.8	29.5	9.4
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	0.7		0.7		0.3
Entergy Louisiana [Member] | Fixed Transmission Rights (FTRs) [Member] | Not Designated As Hedging Instrument [Member] | Prepayments And Other [Member]
Effect Of Derivative Instruments Not Designated As Hedging Instruments On The Consolidated Statements Of Income [Line Items]
Derivative Asset	4.8		4.8		4.2
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					0.3
Derivative, Collateral, Right to Reclaim Cash					0.0
Derivative Liability					0.3
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					1.3
Derivative, Collateral, Right to Reclaim Cash					0.0
Derivative Liability					1.3
Entergy Louisiana [Member] | Natural Gas Swaps [Member] | Not Designated As Hedging Instrument [Member] | Other Deferred Debits And Other Assets [Member]
Effect Of Derivative Instruments Not Designated As Hedging Instruments On The Consolidated Statements Of Income [Line Items]
Derivative Asset	0.4		0.4		0.5
Entergy Louisiana [Member] | Natural Gas Swaps [Member] | Not Designated As Hedging Instrument [Member] | Prepayments And Other [Member]
Effect Of Derivative Instruments Not Designated As Hedging Instruments On The Consolidated Statements Of Income [Line Items]
Derivative Asset	5.0		5.0		0.8
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	4.9		6.7	(1.3)
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	5.9	5.4	18.2	10.7
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	0.9		0.9		0.2
Entergy Mississippi [Member] | Fixed Transmission Rights (FTRs) [Member] | Not Designated As Hedging Instrument [Member] | Prepayments And Other [Member]
Effect Of Derivative Instruments Not Designated As Hedging Instruments On The Consolidated Statements Of Income [Line Items]
Derivative Asset	2.0		2.0		0.6
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					5.0
Derivative, Collateral, Right to Reclaim Cash					0.0
Derivative Liability					5.0
Entergy Mississippi [Member] | Natural Gas Swaps [Member] | Not Designated As Hedging Instrument [Member] | Prepayments And Other [Member]
Effect Of Derivative Instruments Not Designated As Hedging Instruments On The Consolidated Statements Of Income [Line Items]
Derivative Asset	9.6		9.6
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	13.2	(2.5)	18.3	(7.7)
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	0.7	(0.4)	7.9	(0.5)
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	0.3		0.3		0.2
Entergy New Orleans [Member] | Fixed Transmission Rights (FTRs) [Member] | Not Designated As Hedging Instrument [Member] | Prepayments And Other [Member]
Effect Of Derivative Instruments Not Designated As Hedging Instruments On The Consolidated Statements Of Income [Line Items]
Derivative Asset	0.6		0.6		0.1
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					0.3
Derivative, Collateral, Right to Reclaim Cash					0.0
Derivative Liability					0.3
Entergy New Orleans [Member] | Natural Gas Swaps [Member] | Not Designated As Hedging Instrument [Member] | Prepayments And Other [Member]
Effect Of Derivative Instruments Not Designated As Hedging Instruments On The Consolidated Statements Of Income [Line Items]
Derivative Asset	0.1		0.1
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	0.1			(0.4)
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	0.8	0.2	2.0	0.6
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	2.3		2.3		0.5
Entergy Texas [Member] | Fixed Transmission Rights (FTRs) [Member] | Not Designated As Hedging Instrument [Member] | Prepayments And Other [Member]
Effect Of Derivative Instruments Not Designated As Hedging Instruments On The Consolidated Statements Of Income [Line Items]
Derivative Asset	3.8		3.8		$ 1.6
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	$ 4.8	$ 5.3	$ 82.7	$ 7.6