Risk Management and Fair Values (Narrative) (Details) $ in Millions	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2016 USD ($) MWh MMBTU	Jun. 30, 2015 USD ($)	Jun. 30, 2016 USD ($) MWh MMBTU counterparty	Jun. 30, 2015 USD ($)	Dec. 31, 2015 USD ($) counterparty
Risk Management and Fair Values [Abstract]
Letters of Credit Held	$ 23.0		$ 23.0
Letters of Credit Outstanding, Amount	1.0		1.0
Cash collateral posted	1.0		1.0		$ 9.0
Derivative, Collateral, Obligation to Return Cash					$ 68.0
Cash flow hedges relating to power sales as part of net unrealized gains			53.0
Reclassified from accumulated other comprehensive income (OCI) to operating revenues			$ 51.0
Number of Derivative Contract Counterparties in a Liability Position | counterparty			4		2
Maturity of cash flow hedges, Tax	$ 16.0	$ 27.0	$ 70.0	$ 32.0
Maximum length of time over which Company is currently hedging the variability in future cash flows for forecasted power transactions, years			2 years
Planned generation sold forward from non utility nuclear power plants for the remainder of the period			87.00%
Planned Generation Sold Forward under financial derivatives	60.00%		60.00%
Total planned generation for remainder of the period | MWh			18,000,000
Total volume of natural gas swaps outstanding (MMBtu) | MMBTU	32,588,000		32,588,000
Total volume of fixed transmission rights outstanding | MWh	103,995,000		103,995,000
Change in cash flow hedges due to ineffectiveness	$ (3.0)	2.0	$ 0.0	1.0
Dollar amount of hedge contract in a liability position	7.0		$ 7.0		$ 2.0
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset and Liability Unrealized Gains (Loss) Included in Earnings	$ (6.0)	$ (1.0)		$ (7.0)
Entergy Arkansas [Member]
Risk Management and Fair Values [Abstract]
Total volume of fixed transmission rights outstanding | MWh	23,627,000		23,627,000
Entergy Louisiana [Member]
Risk Management and Fair Values [Abstract]
Total volume of natural gas swaps outstanding (MMBtu) | MMBTU	26,370,000		26,370,000
Total volume of fixed transmission rights outstanding | MWh	44,556,000		44,556,000
Entergy Mississippi [Member]
Risk Management and Fair Values [Abstract]
Total volume of natural gas swaps outstanding (MMBtu) | MMBTU	5,950,000		5,950,000
Total volume of fixed transmission rights outstanding | MWh	16,903,000		16,903,000
Entergy New Orleans [Member]
Risk Management and Fair Values [Abstract]
Total volume of natural gas swaps outstanding (MMBtu) | MMBTU	268,000		268,000
Total volume of fixed transmission rights outstanding | MWh	5,064,000		5,064,000
Entergy Texas [Member]
Risk Management and Fair Values [Abstract]
Letters of Credit Outstanding, Amount	$ 1.4		$ 1.4
Total volume of fixed transmission rights outstanding | MWh	13,301,000		13,301,000