Risk Management and Fair Values (Narrative) (Details) $ in Thousands, TWh in Millions	3 Months Ended			9 Months Ended		12 Months Ended
	Dec. 31, 2018 TWh	Sep. 30, 2018 USD ($) GWh MMBTU	Sep. 30, 2017 USD ($)	Sep. 30, 2018 USD ($) GWh MMBTU counterparty	Sep. 30, 2017 USD ($)	Dec. 31, 2017 USD ($) counterparty
Risk Management and Fair Values [Abstract]
Cash flow hedges relating to power sales as part of net unrealized gains				$ (58,000)
Reclassified from accumulated other comprehensive income (OCI) to operating revenues				(47,000)
Maturity of cash flow hedges, Tax		$ (2,000)	$ 8,000	$ (8,000)	$ 30,000
Maximum length of time over which Company is currently hedging the variability in future cash flows for forecasted power transactions, years				2 years 6 months
Total volume of natural gas swaps outstanding (MMBtu) | MMBTU		13,814,000		13,814,000
Total volume of fixed transmission rights outstanding | GWh		77,520		77,520
Change in cash flow hedges due to ineffectiveness		$ (3,100)	2,400	$ (5,200)	6,400
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset and Liability Unrealized Gains (Loss) Included in Earnings		1,700	$ 400	1,100	$ 1,000
Entergy Arkansas [Member]
Risk Management and Fair Values [Abstract]
Letters of Credit Outstanding, Amount		$ 1,000		$ 1,000		$ 200
Total volume of fixed transmission rights outstanding | GWh		17,557		17,557
Entergy Louisiana [Member]
Risk Management and Fair Values [Abstract]
Total volume of natural gas swaps outstanding (MMBtu) | MMBTU		6,300,000		6,300,000
Total volume of fixed transmission rights outstanding | GWh		33,144		33,144
Entergy Mississippi [Member]
Risk Management and Fair Values [Abstract]
Letters of Credit Outstanding, Amount		$ 200		$ 200		100
Total volume of natural gas swaps outstanding (MMBtu) | MMBTU		6,790,000		6,790,000
Total volume of fixed transmission rights outstanding | GWh		10,295		10,295
Entergy New Orleans [Member]
Risk Management and Fair Values [Abstract]
Total volume of natural gas swaps outstanding (MMBtu) | MMBTU		724,000		724,000
Total volume of fixed transmission rights outstanding | GWh		3,758		3,758
Entergy Texas [Member]
Risk Management and Fair Values [Abstract]
Letters of Credit Outstanding, Amount		$ 3,600		$ 3,600		50
Total volume of fixed transmission rights outstanding | GWh		12,441		12,441
Entergy Wholesale Commodities [Member]
Risk Management and Fair Values [Abstract]
Cash collateral posted		$ 30,000		$ 30,000		1,000
Derivative, Collateral, Obligation to Return Cash						4,000
Letters of Credit Held						$ 34,000
Number of Derivative Contract Counterparties in a Liability Position | counterparty				7		8
Dollar amount of hedge contract in a liability position		68,000		$ 68,000		$ 65,000
Utility [Member]
Risk Management and Fair Values [Abstract]
Letters of Credit Outstanding, Amount		$ 5,000		$ 5,000
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	87.00%
Total planned generation for remainder of the period | TWh	6.7