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
	Mar. 31, 2021	Mar. 31, 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	$ (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	7.0	(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	128.0	13.0
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	0.4
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	1.4		$ 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	26.1	4.6
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	0.2		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	1.2		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		0.5
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	1.0		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	1.8	(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	12.3	5.3
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	0.4		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	0.3		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	2.3		5.0
Derivative, Collateral, Right to Reclaim Cash	0.0		0.0
Derivative Liability	2.3		5.0
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	5.2	(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	7.2	(0.1)
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	0.1		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	0.1		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] | 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	1.3	0.4
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			0.5
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	0.5		$ 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	$ 77.9	$ 2.4