Risk Management and Fair Values (Fair Values Of Derivative Instruments) (Details) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Assets:
Derivative, Collateral, Obligation to Return Cash		$ (1.0)
Liabilities:
Letters of Credit Outstanding, Amount	$ 6.0
Entergy Wholesale Commodities [Member]
Derivatives, Fair Value [Line Items]
Cash collateral posted	9.0	11.0
Assets:
Derivative, Collateral, Obligation to Return Cash		(1.0)
Liabilities:
Letters of Credit Held	95.0	98.0
Other Non-Current Liabilities [Member] \| Natural Gas Swaps [Member] \| Utility [Member] \| Not Designated As Hedging Instrument [Member]
Liabilities:
Derivative Liability, Fair Value, Gross Liability	2.0	2.0
Derivative, Collateral, Right to Reclaim Cash	0.0	0.0
Derivative Liability	2.0	2.0
Other Deferred Debits And Other Assets [Member] \| Electricity Swaps And Options [Member] \| Entergy Wholesale Commodities [Member] \| Designated As Hedging Instrument [Member]
Assets:
Derivative Asset		17.0
Derivative Asset, Fair Value, Gross Asset		17.0
Derivative, Collateral, Obligation to Return Cash		0.0
Other Deferred Debits And Other Assets [Member] \| Natural Gas Swaps [Member] \| Utility [Member] \| Not Designated As Hedging Instrument [Member]
Assets:
Derivative Asset	1.0	1.0
Derivative Asset, Fair Value, Gross Asset	1.0	1.0
Derivative, Collateral, Obligation to Return Cash		0.0
Prepayments And Other [Member] \| Electricity Swaps And Options [Member] \| Entergy Wholesale Commodities [Member] \| Designated As Hedging Instrument [Member]
Assets:
Derivative Asset	81.0	91.0
Derivative Asset, Fair Value, Gross Asset	81.0	92.0
Derivative, Collateral, Obligation to Return Cash	0.0	(1.0)
Prepayments And Other [Member] \| Electricity Swaps And Options [Member] \| Entergy Wholesale Commodities [Member] \| Not Designated As Hedging Instrument [Member]
Assets:
Derivative Asset	4.0	10.0
Derivative Asset, Fair Value, Gross Asset	8.0	11.0
Derivative, Collateral, Obligation to Return Cash	(4.0)	(1.0)
Prepayments And Other [Member] \| Financial Transmission Rights (FTRs) [Member] \| Utility and Entergy Wholesale Commodities [Member] \| Not Designated As Hedging Instrument [Member]
Assets:
Derivative Asset	4.0	10.0
Derivative Asset, Fair Value, Gross Asset	4.0	10.0
Derivative, Collateral, Obligation to Return Cash		0.0
Other Current Liabilities [Member] \| Electricity Swaps And Options [Member] \| Entergy Wholesale Commodities [Member] \| Designated As Hedging Instrument [Member]
Liabilities:
Derivative Liability, Fair Value, Gross Liability		1.0
Derivative, Collateral, Right to Reclaim Cash		(1.0)
Derivative Liability		0.0
Other Current Liabilities [Member] \| Electricity Swaps And Options [Member] \| Entergy Wholesale Commodities [Member] \| Not Designated As Hedging Instrument [Member]
Liabilities:
Derivative Liability, Fair Value, Gross Liability	3.0	2.0
Derivative, Collateral, Right to Reclaim Cash	(3.0)	(2.0)
Derivative Liability	0.0	0.0
Other Current Liabilities [Member] \| Natural Gas Swaps [Member] \| Utility [Member] \| Not Designated As Hedging Instrument [Member]
Liabilities:
Derivative Liability, Fair Value, Gross Liability	7.0	5.0
Derivative, Collateral, Right to Reclaim Cash	0.0	0.0
Derivative Liability	7.0	5.0
Entergy Louisiana [Member] \| Other Non-Current Liabilities [Member] \| Natural Gas Swaps [Member] \| Not Designated As Hedging Instrument [Member]
Liabilities:
Derivative Liability, Fair Value, Gross Liability	2.3	2.2
Derivative, Collateral, Right to Reclaim Cash	0.0	0.0
Derivative Liability	2.3	2.2
Entergy Louisiana [Member] \| Other Deferred Debits And Other Assets [Member] \| Natural Gas Swaps [Member] \| Not Designated As Hedging Instrument [Member]
Assets:
Derivative Asset	0.9	0.8
Derivative Asset, Fair Value, Gross Asset	0.9	0.8
Derivative, Collateral, Obligation to Return Cash	0.0	0.0
Entergy Louisiana [Member] \| Prepayments And Other [Member] \| Natural Gas Swaps [Member] \| Not Designated As Hedging Instrument [Member]
Assets:
Derivative Asset	0.2
Derivative Asset, Fair Value, Gross Asset	0.2
Derivative, Collateral, Obligation to Return Cash	0.0
Entergy Louisiana [Member] \| Prepayments And Other [Member] \| Financial Transmission Rights (FTRs) [Member] \| Not Designated As Hedging Instrument [Member]
Assets:
Derivative Asset	1.9	4.5
Derivative Asset, Fair Value, Gross Asset	2.0	4.5
Derivative, Collateral, Obligation to Return Cash	0.1	0.0
Entergy Louisiana [Member] \| Other Current Liabilities [Member] \| Natural Gas Swaps [Member] \| Not Designated As Hedging Instrument [Member]
Liabilities:
Derivative Liability, Fair Value, Gross Liability	2.5	2.4
Derivative, Collateral, Right to Reclaim Cash	0.0	0.0
Derivative Liability	2.5	2.4
Entergy Mississippi [Member]
Liabilities:
Letters of Credit Outstanding, Amount	0.2	0.2
Entergy Mississippi [Member] \| Prepayments And Other [Member] \| Financial Transmission Rights (FTRs) [Member] \| Not Designated As Hedging Instrument [Member]
Assets:
Derivative Asset	0.3	0.8
Derivative Asset, Fair Value, Gross Asset	0.3	0.8
Derivative, Collateral, Obligation to Return Cash	0.0	0.0
Entergy Mississippi [Member] \| Other Current Liabilities [Member] \| Natural Gas Swaps [Member] \| Not Designated As Hedging Instrument [Member]
Liabilities:
Derivative Liability, Fair Value, Gross Liability	4.4	2.3
Derivative, Collateral, Right to Reclaim Cash	0.0	0.0
Derivative Liability	4.4	2.3
Entergy New Orleans [Member] \| Prepayments And Other [Member] \| Financial Transmission Rights (FTRs) [Member] \| Not Designated As Hedging Instrument [Member]
Assets:
Derivative Asset		0.3
Derivative Asset, Fair Value, Gross Asset		0.3
Derivative, Collateral, Obligation to Return Cash		0.0
Entergy New Orleans [Member] \| Other Current Liabilities [Member] \| Natural Gas Swaps [Member] \| Not Designated As Hedging Instrument [Member]
Liabilities:
Derivative Liability, Fair Value, Gross Liability		0.2
Derivative, Collateral, Right to Reclaim Cash		0.0
Derivative Liability		0.2
Entergy Arkansas [Member] \| Prepayments And Other [Member] \| Financial Transmission Rights (FTRs) [Member] \| Not Designated As Hedging Instrument [Member]
Assets:
Derivative Asset	1.1	3.3
Derivative Asset, Fair Value, Gross Asset	1.1	3.4
Derivative, Collateral, Obligation to Return Cash	0.0	(0.1)
Entergy Texas [Member] \| Prepayments And Other [Member] \| Financial Transmission Rights (FTRs) [Member] \| Not Designated As Hedging Instrument [Member]
Assets:
Derivative Asset	0.3	0.9
Derivative Asset, Fair Value, Gross Asset	0.3	1.0
Derivative, Collateral, Obligation to Return Cash	$ 0.0	$ 0.1

Letters of credit posted to Entergy by its counterparties

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