Risk Management and Fair Values (Narrative) (Details) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015 USD ($) MMBTU MWh	Jun. 30, 2014 USD ($)	Jun. 30, 2015 USD ($) MMBTU MWh counterparty	Jun. 30, 2014 USD ($) counterparty	Dec. 31, 2014 USD ($)
Risk Management and Fair Values [Abstract]
Cash Collateral for Borrowed Securities	$ 20.0		$ 20.0
Cash collateral posted	8.0	$ 13.0	8.0	$ 13.0
Cash flow hedges relating to power sales as part of net unrealized gains			170.0
Reclassified from accumulated other comprehensive income (OCI) to operating revenues			$ 131.0
Number of Derivative Contract Counterparties in a Liability Position | counterparty			1	10
Maturity of cash flow hedges, Tax	$ 27.0		$ 32.0	$ (68.0)
Maximum length of time over which Company is currently hedging the variability in future cash flows for forecasted power transactions, years			3 years
Planned generation sold forward from non utility nuclear power plants for the remainder of the period			88.00%
Planned Generation Sold Forward under financial derivatives	65.00%		65.00%
Total planned generation for remainder of the period | MWh			18,000,000
Total volume of natural gas swaps outstanding (MMBtu) | MMBTU	27,620,000		27,620,000
Total volume of fixed transmission rights outstanding | MWh	106,735,000		106,735,000
Change in cash flow hedges due to ineffectiveness	$ 2.0	0.8	$ 1.0	1.8
Dollar amount of hedge contract in a liability position	5.0	93.0	5.0	93.0
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset and Liability Unrealized Gains (Loss) Included in Earnings	$ (1.0)	$ 34.0	$ (7.0)	$ 86.0
Entergy Arkansas [Member]
Risk Management and Fair Values [Abstract]
Total volume of fixed transmission rights outstanding | MWh	21,817,000		21,817,000
Entergy Gulf States Louisiana [Member]
Risk Management and Fair Values [Abstract]
Total volume of natural gas swaps outstanding (MMBtu) | MMBTU	10,870,000		10,870,000
Total volume of fixed transmission rights outstanding | MWh	19,918,000		19,918,000
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	11,820,000		11,820,000
Total volume of fixed transmission rights outstanding | MWh	27,839,000		27,839,000
Entergy Mississippi [Member]
Risk Management and Fair Values [Abstract]
Total volume of natural gas swaps outstanding (MMBtu) | MMBTU	4,630,000		4,630,000
Total volume of fixed transmission rights outstanding | MWh	15,560,000		15,560,000
Entergy New Orleans [Member]
Risk Management and Fair Values [Abstract]
Total volume of natural gas swaps outstanding (MMBtu) | MMBTU	300,000		300,000
Total volume of fixed transmission rights outstanding | MWh	7,718,000		7,718,000
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	11,647,000		11,647,000
Fixed Transmission Rights (FTRs) [Member] | Entergy Texas [Member]
Risk Management and Fair Values [Abstract]
Letters of Credit Outstanding, Amount	$ 0.6		$ 0.6
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	19.0		19.0		$ 25.0
Letters of Credit Outstanding, Amount	1.0		1.0
Cash collateral posted	7.0		7.0
Letters of Credit Held	$ 1.0		$ 1.0