Risk Management and Fair Values (Assets And Liabilities At Fair Value On A Recurring Basis) (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Liabilities at fair value on a recurring basis
Average Coupon Rate of Debt Securities Percentage	3.54%
Fair Value, Measurements, Recurring [Member]
Assets at fair value on a recurring basis
Temporary cash investments	$ 262.0	$ 420.0
Total	5,160.0	5,233.0
Liabilities at fair value on a recurring basis
Total	39	21
Gas Hedge Contracts [Member] | Fair Value, Measurements, Recurring [Member]
Liabilities at fair value on a recurring basis
Liabilities, Fair Value Disclosure on Recurring Basis	3.0	8.0
Power Contracts Liabilities [Member] | Fair Value, Measurements, Recurring [Member]
Liabilities at fair value on a recurring basis
Liabilities, Fair Value Disclosure on Recurring Basis	36.0	13.0
Equity Securities [Member] | Fair Value, Measurements, Recurring [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	2,888.0	2,459.0
Debt Securities [Member] | Fair Value, Measurements, Recurring [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	1,740.0	1,731.0
Power Contracts Assets [Member] | Fair Value, Measurements, Recurring [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	85.0	191.0
Securitization Recovery Trust Account [Member] | Fair Value, Measurements, Recurring [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	50.0	46.0
Storm Reserve Escrow Account [Member] | Fair Value, Measurements, Recurring [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	135.0	386.0
Fair Value Inputs Level 1 [Member]
Assets at fair value on a recurring basis
Temporary cash investments	262.0	420.0
Total	1,606.0	1,979.0
Liabilities at fair value on a recurring basis
Total	3	8
Fair Value Inputs Level 1 [Member] | Gas Hedge Contracts [Member]
Liabilities at fair value on a recurring basis
Liabilities, Fair Value Disclosure on Recurring Basis	3.0	8.0
Fair Value Inputs Level 1 [Member] | Power Contracts Liabilities [Member]
Liabilities at fair value on a recurring basis
Liabilities, Fair Value Disclosure on Recurring Basis
Fair Value Inputs Level 1 [Member] | Equity Securities [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	418.0	358.0
Fair Value Inputs Level 1 [Member] | Debt Securities [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	741.0	769.0
Fair Value Inputs Level 1 [Member] | Power Contracts Assets [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments
Fair Value Inputs Level 1 [Member] | Securitization Recovery Trust Account [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	50.0	46.0
Fair Value Inputs Level 1 [Member] | Storm Reserve Escrow Account [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	135.0	386.0
Fair Value Inputs Level 2 [Member]
Assets at fair value on a recurring basis
Temporary cash investments
Total	3,469.0	3,063.0
Liabilities at fair value on a recurring basis
Total
Fair Value Inputs Level 2 [Member] | Gas Hedge Contracts [Member]
Liabilities at fair value on a recurring basis
Liabilities, Fair Value Disclosure on Recurring Basis
Fair Value Inputs Level 2 [Member] | Power Contracts Liabilities [Member]
Liabilities at fair value on a recurring basis
Liabilities, Fair Value Disclosure on Recurring Basis
Fair Value Inputs Level 2 [Member] | Equity Securities [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	2,470.0	2,101.0
Fair Value Inputs Level 2 [Member] | Debt Securities [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	999.0	962.0
Fair Value Inputs Level 2 [Member] | Power Contracts Assets [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments
Fair Value Inputs Level 2 [Member] | Securitization Recovery Trust Account [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments
Fair Value Inputs Level 2 [Member] | Storm Reserve Escrow Account [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments
Fair Value Inputs Level 3 [Member]
Assets at fair value on a recurring basis
Temporary cash investments
Total	85.0	191.0
Liabilities at fair value on a recurring basis
Total	36	13
Fair Value Inputs Level 3 [Member] | Gas Hedge Contracts [Member]
Liabilities at fair value on a recurring basis
Liabilities, Fair Value Disclosure on Recurring Basis
Fair Value Inputs Level 3 [Member] | Power Contracts Liabilities [Member]
Liabilities at fair value on a recurring basis
Liabilities, Fair Value Disclosure on Recurring Basis	36.0	13.0
Fair Value Inputs Level 3 [Member] | Equity Securities [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments
Fair Value Inputs Level 3 [Member] | Debt Securities [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments
Fair Value Inputs Level 3 [Member] | Power Contracts Assets [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	85.0	191.0
Fair Value Inputs Level 3 [Member] | Securitization Recovery Trust Account [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments
Fair Value Inputs Level 3 [Member] | Storm Reserve Escrow Account [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments
Entergy Arkansas [Member]
Assets at fair value on a recurring basis
Temporary cash investments	41.7	24.9
Total	757.4	667.9
Liabilities at fair value on a recurring basis
Average Coupon Rate of Debt Securities Percentage	2.83%
Entergy Arkansas [Member] | Equity Securities [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	430.8	384.0
Entergy Arkansas [Member] | Debt Securities [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	239.0	216.6
Entergy Arkansas [Member] | Securitization Recovery Trust Account [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	7.9	4.4
Entergy Arkansas [Member] | Storm Reserve Escrow Account [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	38.0	38.0
Entergy Arkansas [Member] | Fair Value Inputs Level 1 [Member]
Assets at fair value on a recurring basis
Temporary cash investments	41.7	24.9
Total	160.6	171.1
Entergy Arkansas [Member] | Fair Value Inputs Level 1 [Member] | Equity Securities [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	4.2	9.5
Entergy Arkansas [Member] | Fair Value Inputs Level 1 [Member] | Debt Securities [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	68.8	94.3
Entergy Arkansas [Member] | Fair Value Inputs Level 1 [Member] | Securitization Recovery Trust Account [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	7.9	4.4
Entergy Arkansas [Member] | Fair Value Inputs Level 1 [Member] | Storm Reserve Escrow Account [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	38.0	38.0
Entergy Arkansas [Member] | Fair Value Inputs Level 2 [Member]
Assets at fair value on a recurring basis
Total	596.8	496.8
Entergy Arkansas [Member] | Fair Value Inputs Level 2 [Member] | Equity Securities [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	426.6	374.5
Entergy Arkansas [Member] | Fair Value Inputs Level 2 [Member] | Debt Securities [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	170.2	122.3
Entergy Gulf States Louisiana [Member]
Assets at fair value on a recurring basis
Temporary cash investments	0.6	0.6
Total	559.7	565.0
Liabilities at fair value on a recurring basis
Average Coupon Rate of Debt Securities Percentage	4.58%
Entergy Gulf States Louisiana [Member] | Gas Hedge Contracts [Member]
Liabilities at fair value on a recurring basis
Liabilities, Fair Value Disclosure on Recurring Basis	1.3	2.6
Entergy Gulf States Louisiana [Member] | Equity Securities [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	347.2	288.5
Entergy Gulf States Louisiana [Member] | Debt Securities [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	190.4	188.9
Entergy Gulf States Louisiana [Member] | Storm Reserve Escrow Account [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	21.5	87.0
Entergy Gulf States Louisiana [Member] | Fair Value Inputs Level 1 [Member]
Assets at fair value on a recurring basis
Temporary cash investments	0.6	0.6
Total	81.0	142.6
Entergy Gulf States Louisiana [Member] | Fair Value Inputs Level 1 [Member] | Gas Hedge Contracts [Member]
Liabilities at fair value on a recurring basis
Liabilities, Fair Value Disclosure on Recurring Basis	1.3	2.6
Entergy Gulf States Louisiana [Member] | Fair Value Inputs Level 1 [Member] | Equity Securities [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	5.6	5.5
Entergy Gulf States Louisiana [Member] | Fair Value Inputs Level 1 [Member] | Debt Securities [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	53.3	49.5
Entergy Gulf States Louisiana [Member] | Fair Value Inputs Level 1 [Member] | Storm Reserve Escrow Account [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	21.5	87.0
Entergy Gulf States Louisiana [Member] | Fair Value Inputs Level 2 [Member]
Assets at fair value on a recurring basis
Total	478.7	422.4
Entergy Gulf States Louisiana [Member] | Fair Value Inputs Level 2 [Member] | Equity Securities [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	341.6	283.0
Entergy Gulf States Louisiana [Member] | Fair Value Inputs Level 2 [Member] | Debt Securities [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	137.1	139.4
Entergy Louisiana [Member]
Assets at fair value on a recurring basis
Temporary cash investments	40.5	29.3
Total	376.4	508.1
Liabilities at fair value on a recurring basis
Average Coupon Rate of Debt Securities Percentage	3.42%
Entergy Louisiana [Member] | Gas Hedge Contracts [Member]
Liabilities at fair value on a recurring basis
Liabilities, Fair Value Disclosure on Recurring Basis	1.4	3.4
Entergy Louisiana [Member] | Equity Securities [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	214.7	175.5
Entergy Louisiana [Member] | Debt Securities [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	110.7	111.9
Entergy Louisiana [Member] | Securitization Recovery Trust Account [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	10.5	4.4
Entergy Louisiana [Member] | Storm Reserve Escrow Account [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments		187.0
Entergy Louisiana [Member] | Fair Value Inputs Level 1 [Member]
Assets at fair value on a recurring basis
Temporary cash investments	40.5	29.3
Total	107.4	275.3
Entergy Louisiana [Member] | Fair Value Inputs Level 1 [Member] | Gas Hedge Contracts [Member]
Liabilities at fair value on a recurring basis
Liabilities, Fair Value Disclosure on Recurring Basis	1.4	3.4
Entergy Louisiana [Member] | Fair Value Inputs Level 1 [Member] | Equity Securities [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	4.6	2.0
Entergy Louisiana [Member] | Fair Value Inputs Level 1 [Member] | Debt Securities [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	51.8	52.6
Entergy Louisiana [Member] | Fair Value Inputs Level 1 [Member] | Securitization Recovery Trust Account [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	10.5	4.4
Entergy Louisiana [Member] | Fair Value Inputs Level 1 [Member] | Storm Reserve Escrow Account [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments		187.0
Entergy Louisiana [Member] | Fair Value Inputs Level 2 [Member]
Assets at fair value on a recurring basis
Total	269.0	232.8
Entergy Louisiana [Member] | Fair Value Inputs Level 2 [Member] | Equity Securities [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	210.1	173.5
Entergy Louisiana [Member] | Fair Value Inputs Level 2 [Member] | Debt Securities [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	58.9	59.3
Entergy Mississippi [Member]
Assets at fair value on a recurring basis
Temporary cash investments		52.4
Total		114.2
Entergy Mississippi [Member] | Gas Hedge Contracts [Member]
Liabilities at fair value on a recurring basis
Liabilities, Fair Value Disclosure on Recurring Basis	0.3	2.2
Entergy Mississippi [Member] | Storm Reserve Escrow Account [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	61.8	61.8
Entergy Mississippi [Member] | Fair Value Inputs Level 1 [Member]
Assets at fair value on a recurring basis
Temporary cash investments		52.4
Total		114.2
Entergy Mississippi [Member] | Fair Value Inputs Level 1 [Member] | Gas Hedge Contracts [Member]
Liabilities at fair value on a recurring basis
Liabilities, Fair Value Disclosure on Recurring Basis	0.3	2.2
Entergy Mississippi [Member] | Fair Value Inputs Level 1 [Member] | Storm Reserve Escrow Account [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	61.8	61.8
Entergy New Orleans
Assets at fair value on a recurring basis
Temporary cash investments	14.4	9.1
Total	23.1	19.7
Entergy New Orleans | Gas Hedge Contracts [Member]
Liabilities at fair value on a recurring basis
Liabilities, Fair Value Disclosure on Recurring Basis	0.2
Entergy New Orleans | Storm Reserve Escrow Account [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	8.7	10.6
Entergy New Orleans | Fair Value Inputs Level 1 [Member]
Assets at fair value on a recurring basis
Temporary cash investments	14.4	9.1
Total	23.1	19.7
Entergy New Orleans | Fair Value Inputs Level 1 [Member] | Gas Hedge Contracts [Member]
Liabilities at fair value on a recurring basis
Liabilities, Fair Value Disclosure on Recurring Basis	0.2
Entergy New Orleans | Fair Value Inputs Level 1 [Member] | Storm Reserve Escrow Account [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	8.7	10.6
Entergy Texas [Member]
Assets at fair value on a recurring basis
Temporary cash investments	19.7	59.7
Total	51.1	97.0
Entergy Texas [Member] | Securitization Recovery Trust Account [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	31.4	37.3
Entergy Texas [Member] | Fair Value Inputs Level 1 [Member]
Assets at fair value on a recurring basis
Temporary cash investments	19.7	59.7
Total	51.1	97.0
Entergy Texas [Member] | Fair Value Inputs Level 1 [Member] | Securitization Recovery Trust Account [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	31.4	37.3
System Energy [Member]
Assets at fair value on a recurring basis
Temporary cash investments	3.1	83.5
Total	566.5	574.1
Liabilities at fair value on a recurring basis
Average Coupon Rate of Debt Securities Percentage	2.57%
System Energy [Member] | Equity Securities [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	343.8	283.6
System Energy [Member] | Debt Securities [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	219.6	207.0
System Energy [Member] | Fair Value Inputs Level 1 [Member]
Assets at fair value on a recurring basis
Temporary cash investments	3.1	83.5
Total	155.7	226.2
System Energy [Member] | Fair Value Inputs Level 1 [Member] | Equity Securities [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	1.0	1.6
System Energy [Member] | Fair Value Inputs Level 1 [Member] | Debt Securities [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	151.6	141.1
System Energy [Member] | Fair Value Inputs Level 2 [Member]
Assets at fair value on a recurring basis
Total	410.8	347.9
System Energy [Member] | Fair Value Inputs Level 2 [Member] | Equity Securities [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	342.8	282.0
System Energy [Member] | Fair Value Inputs Level 2 [Member] | Debt Securities [Member]
Assets at fair value on a recurring basis
Assets other than temporary cash investments	$ 68.0	$ 65.9