Risk Management and Fair Values (Derivative Instruments Not Designated As Hedging Instruments On The Consolidated Statements Of Income) (Details) - Not Designated As Hedging Instrument [Member] - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Competitive Businesses Operating Revenues [Member] | Electricity Swaps And Options [Member]
Effect Of Derivative Instruments Not Designated As Hedging Instruments On The Consolidated Statements Of Income [Line Items]
Amount of gain (loss) recognized in AOCI	$ 25.0	$ 4.0
Amount of gain (loss) recorded in income	0.0	(34.0)
Fuel, Fuel Related Expenses And Gas Purchased For Resale [Member] | Natural Gas Swaps [Member]
Effect Of Derivative Instruments Not Designated As Hedging Instruments On The Consolidated Statements Of Income [Line Items]
Amount of gain (loss) recognized in AOCI	0.0	0.0
Amount of gain (loss) recorded in income	(24.0)	(19.0)
Purchased Power Expense [Member] | Fixed Transmission Rights (FTRs) [Member]
Effect Of Derivative Instruments Not Designated As Hedging Instruments On The Consolidated Statements Of Income [Line Items]
Amount of gain (loss) recognized in AOCI	0.0	0.0
Amount of gain (loss) recorded in income	21.0	33.0
Entergy Arkansas [Member] | Purchased Power Expense [Member] | Fixed Transmission Rights (FTRs) [Member]
Effect Of Derivative Instruments Not Designated As Hedging Instruments On The Consolidated Statements Of Income [Line Items]
Amount of gain (loss) recorded in income	7.8	15.1
Entergy Louisiana [Member] | Fuel, Fuel Related Expenses And Gas Purchased For Resale [Member] | Natural Gas Swaps [Member]
Effect Of Derivative Instruments Not Designated As Hedging Instruments On The Consolidated Statements Of Income [Line Items]
Amount of gain (loss) recorded in income	(19.3)	(16.0)
Entergy Louisiana [Member] | Purchased Power Expense [Member] | Fixed Transmission Rights (FTRs) [Member]
Effect Of Derivative Instruments Not Designated As Hedging Instruments On The Consolidated Statements Of Income [Line Items]
Amount of gain (loss) recorded in income	10.5	14.5
Entergy Mississippi [Member] | Fuel, Fuel Related Expenses And Gas Purchased For Resale [Member] | Natural Gas Swaps [Member]
Effect Of Derivative Instruments Not Designated As Hedging Instruments On The Consolidated Statements Of Income [Line Items]
Amount of gain (loss) recorded in income	(4.1)	(3.0)
Entergy Mississippi [Member] | Purchased Power Expense [Member] | Fixed Transmission Rights (FTRs) [Member]
Effect Of Derivative Instruments Not Designated As Hedging Instruments On The Consolidated Statements Of Income [Line Items]
Amount of gain (loss) recorded in income	0.8	3.3
Entergy New Orleans [Member] | Fuel, Fuel Related Expenses And Gas Purchased For Resale [Member] | Natural Gas Swaps [Member]
Effect Of Derivative Instruments Not Designated As Hedging Instruments On The Consolidated Statements Of Income [Line Items]
Amount of gain (loss) recorded in income	(0.5)	(0.5)
Entergy New Orleans [Member] | Purchased Power Expense [Member] | Fixed Transmission Rights (FTRs) [Member]
Effect Of Derivative Instruments Not Designated As Hedging Instruments On The Consolidated Statements Of Income [Line Items]
Amount of gain (loss) recorded in income	0.5	1.6
Entergy Texas [Member] | Purchased Power Expense [Member] | Fixed Transmission Rights (FTRs) [Member]
Effect Of Derivative Instruments Not Designated As Hedging Instruments On The Consolidated Statements Of Income [Line Items]
Amount of gain (loss) recorded in income	$ 1.5	$ (1.4)