Risk Management and Fair Values (Narrative) (Details) $ in Thousands, TWh in Millions	3 Months Ended		9 Months Ended	12 Months Ended
	Mar. 31, 2018 USD ($) MMBTU GWh counterparty	Mar. 31, 2017 USD ($)	Dec. 31, 2018 TWh	Dec. 31, 2017 USD ($) counterparty
Risk Management and Fair Values [Abstract]
Letters of Credit Outstanding, Amount	$ 69,000			$ 34,000
Cash collateral posted	1,000			1,000
Derivative, Collateral, Obligation to Return Cash	6,000			4,000
Cash flow hedges relating to power sales as part of net unrealized gains	65,000
Reclassified from accumulated other comprehensive income (OCI) to operating revenues	41,000
Maturity of cash flow hedges, Tax	$ (6,000)	$ 18,000
Maximum length of time over which Company is currently hedging the variability in future cash flows for forecasted power transactions, years	3 years
Total volume of natural gas swaps outstanding (MMBtu) | MMBTU	63,890,000
Total volume of fixed transmission rights outstanding | GWh	18,490
Change in cash flow hedges due to ineffectiveness	$ 13,300	(1,000)
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset and Liability Unrealized Gains (Loss) Included in Earnings	200	400
Entergy Arkansas [Member]
Risk Management and Fair Values [Abstract]
Letters of Credit Outstanding, Amount	$ 200			200
Total volume of fixed transmission rights outstanding | GWh	4,153
Entergy Louisiana [Member]
Risk Management and Fair Values [Abstract]
Total volume of natural gas swaps outstanding (MMBtu) | MMBTU	53,730,000
Total volume of fixed transmission rights outstanding | GWh	8,162
Entergy Mississippi [Member]
Risk Management and Fair Values [Abstract]
Letters of Credit Outstanding, Amount	$ 100			100
Total volume of natural gas swaps outstanding (MMBtu) | MMBTU	10,160,000
Total volume of fixed transmission rights outstanding | GWh	2,562
Entergy New Orleans [Member]
Risk Management and Fair Values [Abstract]
Total volume of fixed transmission rights outstanding | GWh	943
Entergy Texas [Member]
Risk Management and Fair Values [Abstract]
Letters of Credit Outstanding, Amount	$ 200			50
Total volume of fixed transmission rights outstanding | GWh	2,541
Electricity Swaps And Options [Member]
Fair Value, Measurement With Unobservable Inputs Reconciliation, Recurring Basis, Asset and Liability, Realized Gain (Loss) Included In Earnings	$ 14,000	0
Fixed Transmission Rights (FTRs) [Member]
Fair Value, Measurement With Unobservable Inputs Reconciliation, Recurring Basis, Asset and Liability, Realized Gain (Loss) Included In Earnings	(1,000)	$ 0
Entergy Wholesale Commodities [Member]
Risk Management and Fair Values [Abstract]
Letters of Credit Outstanding, Amount				34,000
Cash collateral posted	500			1,000
Derivative, Collateral, Obligation to Return Cash	6,000			$ 4,000
Letters of Credit Held	$ 69,000
Number of Derivative Contract Counterparties in a Liability Position | counterparty	1			8
Dollar amount of hedge contract in a liability position	$ 300			$ 65,000
Subsequent Event [Member]
Risk Management and Fair Values [Abstract]
Planned generation sold forward from non utility nuclear power plants for the remainder of the period			98.00%
Planned Generation From Non Nuclear Power Plants Sold Forward Under Financial Hedges			79.00%
Total planned generation for remainder of the period | TWh			20.7