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, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 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)	$ 0.0
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	37.0	(1.0)	62.0	(3.0)
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	18.0	33.0	162.0	61.0
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	1.0		1.0
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	2.4		2.4		$ 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	4.5	5.2	34.0	14.7
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	1.5		1.5		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	2.6		2.6		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	2.3		2.3		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	19.6		19.6		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	9.4	1.4	16.1	1.4
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	8.7	3.1	26.8	13.9
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] | 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		0.6
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	23.2		23.2
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	25.6	(1.5)	44.0	(4.0)
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	1.5	1.3	9.4	0.7
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	0.3		0.3		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	2.3		2.3
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	2.2	(0.5)	2.2	(0.5)
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	0.6	0.1	2.6	0.8
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	0.8		0.8		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	1.7		1.7		$ 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	$ 2.6	$ 22.8	$ 85.3	$ 30.5