Risk Management and Fair Values (Narrative) (Details) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015 USD ($) MMBTU MWh	Sep. 30, 2014 USD ($)	Sep. 30, 2015 USD ($) MMBTU MWh counterparty	Sep. 30, 2014 USD ($) counterparty	Dec. 31, 2014 USD ($)
Risk Management and Fair Values [Abstract]
Cash collateral posted		$ 4.0		$ 4.0
Cash flow hedges relating to power sales as part of net unrealized gains			$ (133.0)
Reclassified from accumulated other comprehensive income (OCI) to operating revenues			$ (99.0)
Number of Derivative Contract Counterparties in a Liability Position | counterparty			2	9
Maturity of cash flow hedges, Tax	$ 30.0	5.0	$ 61.0	$ (64.0)
Maximum length of time over which Company is currently hedging the variability in future cash flows for forecasted power transactions, years			2 years 3 months 1 day
Planned generation sold forward from non utility nuclear power plants for the remainder of the period			86.00%
Planned Generation Sold Forward under financial derivatives	66.00%		66.00%
Total planned generation for remainder of the period | MWh			9,000,000
Total volume of natural gas swaps outstanding (MMBtu) | MMBTU	28,673,000		28,673,000
Total volume of fixed transmission rights outstanding | MWh	76,215,000		76,215,000
Change in cash flow hedges due to ineffectiveness	$ (0.9)	(1.0)	$ 0.1	0.8
Dollar amount of hedge contract in a liability position	7.0	96.0	7.0	96.0
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset and Liability Unrealized Gains (Loss) Included in Earnings	$ 12.0	$ 4.0	$ 5.0	$ 90.0
Entergy Arkansas [Member]
Risk Management and Fair Values [Abstract]
Total volume of fixed transmission rights outstanding | MWh	15,577,000		15,577,000
Entergy Louisiana [Member]
Risk Management and Fair Values [Abstract]
Letters of Credit Outstanding, Amount	$ 3.0		$ 3.0
Total volume of natural gas swaps outstanding (MMBtu) | MMBTU	10,770,000		10,770,000
Total volume of fixed transmission rights outstanding | MWh	19,878,000		19,878,000
Entergy Mississippi [Member]
Risk Management and Fair Values [Abstract]
Total volume of natural gas swaps outstanding (MMBtu) | MMBTU	4,390,000		4,390,000
Total volume of fixed transmission rights outstanding | MWh	10,628,000		10,628,000
Entergy New Orleans [Member]
Risk Management and Fair Values [Abstract]
Total volume of natural gas swaps outstanding (MMBtu) | MMBTU	1,193,000		1,193,000
Total volume of fixed transmission rights outstanding | MWh	5,629,000		5,629,000
Entergy Texas [Member]
Risk Management and Fair Values [Abstract]
Letters of Credit Outstanding, Amount	$ 1.3		$ 1.3
Total volume of fixed transmission rights outstanding | MWh	8,456,000		8,456,000
Utility and Entergy Wholesale Commodities [Member] | Electricity Swaps And Options And Fixed Transmission Rights [Member]
Risk Management and Fair Values [Abstract]
Cash Collateral for Borrowed Securities					$ 25.0