Risk Management and Fair Values (Assets And Liabilities At Fair Value On A Recurring Basis) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Assets at fair value on a recurring basis
Available-for-sale Securities	$ 5,724.0	$ 5,350.0
Fair Value, Measurements, Recurring [Member]
Assets at fair value on a recurring basis
Temporary cash investments	1,058.0	1,287.0
Total	7,311.0	7,330.0
Liabilities at fair value on a recurring basis
Total		15.0
Gas Hedge Contracts [Member] | Fair Value, Measurements, Recurring [Member]
Liabilities at fair value on a recurring basis
Liabilities, Fair Value Disclosure on Recurring Basis		9.0
Power Contracts Liabilities [Member] | Fair Value, Measurements, Recurring [Member]
Liabilities at fair value on a recurring basis
Liabilities, Fair Value Disclosure on Recurring Basis	11.0	6.0
Equity Securities [Member] | Fair Value, Measurements, Recurring [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	480.0	468.0
Debt Securities [Member] | Fair Value, Measurements, Recurring [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	2,213.0	2,155.0
Power Contracts Assets [Member] | Fair Value, Measurements, Recurring [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	16.0	195.0
Securitization Recovery Trust Account [Member] | Fair Value, Measurements, Recurring [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	46.0	50.0
Escrow Accounts [Member] | Fair Value, Measurements, Recurring [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	433.0	425.0
Fixed Transmission Rights (FTRs) [Member] | Fair Value, Measurements, Recurring [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	21.0	23.0
Common trust funds valued using Net Asset Value [Domain] | Fair Value, Measurements, Recurring [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	3,031.0	2,727.0
Gas Hedge Contracts Assets [Member] | Fair Value, Measurements, Recurring [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	13.0
Fair Value Inputs Level 1 [Member]
Assets at fair value on a recurring basis
Temporary cash investments	1,058.0	1,287.0
Total	3,015.0	3,291.0
Liabilities at fair value on a recurring basis
Total		9.0
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		9.0
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	0.0	0.0
Fair Value Inputs Level 1 [Member] | Equity Securities [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	480.0	468.0
Fair Value Inputs Level 1 [Member] | Debt Securities [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	985.0	1,061.0
Fair Value Inputs Level 1 [Member] | Power Contracts Assets [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	0.0	0.0
Fair Value Inputs Level 1 [Member] | Securitization Recovery Trust Account [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	46.0	50.0
Fair Value Inputs Level 1 [Member] | Escrow Accounts [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	433.0	425.0
Fair Value Inputs Level 1 [Member] | Fixed Transmission Rights (FTRs) [Member] | Fair Value, Measurements, Recurring [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	0.0	0.0
Fair Value Inputs Level 1 [Member] | Gas Hedge Contracts Assets [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	13.0
Fair Value Inputs Level 2 [Member]
Assets at fair value on a recurring basis
Temporary cash investments	0.0	0.0
Total	1,228.0	1,094.0
Liabilities at fair value on a recurring basis
Total		0.0
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		0.0
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	0.0	0.0
Fair Value Inputs Level 2 [Member] | Equity Securities [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	0.0	0.0
Fair Value Inputs Level 2 [Member] | Debt Securities [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	1,228.0	1,094.0
Fair Value Inputs Level 2 [Member] | Power Contracts Assets [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	0.0	0.0
Fair Value Inputs Level 2 [Member] | Securitization Recovery Trust Account [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	0.0	0.0
Fair Value Inputs Level 2 [Member] | Escrow Accounts [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	0.0	0.0
Fair Value Inputs Level 2 [Member] | Fixed Transmission Rights (FTRs) [Member] | Fair Value, Measurements, Recurring [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	0.0	0.0
Fair Value Inputs Level 2 [Member] | Gas Hedge Contracts Assets [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	0.0
Fair Value Inputs Level 3 [Member]
Assets at fair value on a recurring basis
Temporary cash investments	0.0	0.0
Total	37.0	218.0
Liabilities at fair value on a recurring basis
Total		6.0
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		0.0
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	11.0	6.0
Fair Value Inputs Level 3 [Member] | Equity Securities [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	0.0	0.0
Fair Value Inputs Level 3 [Member] | Debt Securities [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	0.0	0.0
Fair Value Inputs Level 3 [Member] | Power Contracts Assets [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	16.0	195.0
Fair Value Inputs Level 3 [Member] | Securitization Recovery Trust Account [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	0.0	0.0
Fair Value Inputs Level 3 [Member] | Escrow Accounts [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	0.0	0.0
Fair Value Inputs Level 3 [Member] | Fixed Transmission Rights (FTRs) [Member] | Fair Value, Measurements, Recurring [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	21.0	23.0
Fair Value Inputs Level 3 [Member] | Gas Hedge Contracts Assets [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	0.0
Entergy Texas [Member] | Fair Value, Measurements, Recurring [Member]
Assets at fair value on a recurring basis
Temporary cash investments	5.0
Total	45.6	40.4
Entergy Texas [Member] | Securitization Recovery Trust Account [Member] | Fair Value, Measurements, Recurring [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	37.5	38.2
Entergy Texas [Member] | Fixed Transmission Rights (FTRs) [Member] | Fair Value, Measurements, Recurring [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	3.1	2.2
Entergy Texas [Member] | Fair Value Inputs Level 1 [Member]
Assets at fair value on a recurring basis
Temporary cash investments	5.0
Total	42.5	38.2
Entergy Texas [Member] | Fair Value Inputs Level 1 [Member] | Securitization Recovery Trust Account [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	37.5	38.2
Entergy Texas [Member] | Fair Value Inputs Level 1 [Member] | Fixed Transmission Rights (FTRs) [Member] | Fair Value, Measurements, Recurring [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	0.0	0.0
Entergy Texas [Member] | Fair Value Inputs Level 2 [Member]
Assets at fair value on a recurring basis
Temporary cash investments	0.0
Total	0.0	0.0
Entergy Texas [Member] | Fair Value Inputs Level 2 [Member] | Securitization Recovery Trust Account [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	0.0	0.0
Entergy Texas [Member] | Fair Value Inputs Level 2 [Member] | Fixed Transmission Rights (FTRs) [Member] | Fair Value, Measurements, Recurring [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	0.0	0.0
Entergy Texas [Member] | Fair Value Inputs Level 3 [Member]
Assets at fair value on a recurring basis
Temporary cash investments	0.0
Total	3.1	2.2
Entergy Texas [Member] | Fair Value Inputs Level 3 [Member] | Securitization Recovery Trust Account [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	0.0	0.0
Entergy Texas [Member] | Fair Value Inputs Level 3 [Member] | Fixed Transmission Rights (FTRs) [Member] | Fair Value, Measurements, Recurring [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	3.1	2.2
Entergy New Orleans [Member] | Fair Value, Measurements, Recurring [Member]
Assets at fair value on a recurring basis
Temporary cash investments	103.0	87.8
Total	194.6	174.9
Entergy New Orleans [Member] | Gas Hedge Contracts [Member] | Fair Value, Measurements, Recurring [Member]
Liabilities at fair value on a recurring basis
Liabilities, Fair Value Disclosure on Recurring Basis		0.5
Entergy New Orleans [Member] | Securitization Recovery Trust Account [Member] | Fair Value, Measurements, Recurring [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	1.7	4.6
Entergy New Orleans [Member] | Escrow Accounts [Member] | Fair Value, Measurements, Recurring [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	88.6	81.0
Entergy New Orleans [Member] | Fixed Transmission Rights (FTRs) [Member] | Fair Value, Measurements, Recurring [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	1.1	1.5
Entergy New Orleans [Member] | Gas Hedge Contracts Assets [Member] | Fair Value, Measurements, Recurring [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	0.2
Entergy New Orleans [Member] | Fair Value Inputs Level 1 [Member]
Assets at fair value on a recurring basis
Temporary cash investments	103.0	87.8
Total	193.5	173.4
Entergy New Orleans [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		0.5
Entergy New Orleans [Member] | Fair Value Inputs Level 1 [Member] | Securitization Recovery Trust Account [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	1.7	4.6
Entergy New Orleans [Member] | Fair Value Inputs Level 1 [Member] | Escrow Accounts [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	88.6	81.0
Entergy New Orleans [Member] | Fair Value Inputs Level 1 [Member] | Fixed Transmission Rights (FTRs) [Member] | Fair Value, Measurements, Recurring [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	0.0	0.0
Entergy New Orleans [Member] | Fair Value Inputs Level 1 [Member] | Gas Hedge Contracts Assets [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	0.2
Entergy New Orleans [Member] | Fair Value Inputs Level 2 [Member]
Assets at fair value on a recurring basis
Temporary cash investments	0.0	0.0
Total	0.0	0.0
Entergy New Orleans [Member] | 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		0.0
Entergy New Orleans [Member] | Fair Value Inputs Level 2 [Member] | Securitization Recovery Trust Account [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	0.0	0.0
Entergy New Orleans [Member] | Fair Value Inputs Level 2 [Member] | Escrow Accounts [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	0.0	0.0
Entergy New Orleans [Member] | Fair Value Inputs Level 2 [Member] | Fixed Transmission Rights (FTRs) [Member] | Fair Value, Measurements, Recurring [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	0.0	0.0
Entergy New Orleans [Member] | Fair Value Inputs Level 2 [Member] | Gas Hedge Contracts Assets [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	0.0
Entergy New Orleans [Member] | Fair Value Inputs Level 3 [Member]
Assets at fair value on a recurring basis
Temporary cash investments	0.0	0.0
Total	1.1	1.5
Entergy New Orleans [Member] | 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		0.0
Entergy New Orleans [Member] | Fair Value Inputs Level 3 [Member] | Securitization Recovery Trust Account [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	0.0	0.0
Entergy New Orleans [Member] | Fair Value Inputs Level 3 [Member] | Escrow Accounts [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	0.0	0.0
Entergy New Orleans [Member] | Fair Value Inputs Level 3 [Member] | Fixed Transmission Rights (FTRs) [Member] | Fair Value, Measurements, Recurring [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	1.1	1.5
Entergy New Orleans [Member] | Fair Value Inputs Level 3 [Member] | Gas Hedge Contracts Assets [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	0.0
Entergy Mississippi [Member] | Fair Value, Measurements, Recurring [Member]
Assets at fair value on a recurring basis
Temporary cash investments	76.8	144.2
Total	114.1	188.3
Entergy Mississippi [Member] | Gas Hedge Contracts [Member] | Fair Value, Measurements, Recurring [Member]
Liabilities at fair value on a recurring basis
Liabilities, Fair Value Disclosure on Recurring Basis		1.3
Entergy Mississippi [Member] | Escrow Accounts [Member] | Fair Value, Measurements, Recurring [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	31.8	41.7
Entergy Mississippi [Member] | Fixed Transmission Rights (FTRs) [Member] | Fair Value, Measurements, Recurring [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	3.2	2.4
Entergy Mississippi [Member] | Gas Hedge Contracts Assets [Member] | Fair Value, Measurements, Recurring [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	2.3
Entergy Mississippi [Member] | Fair Value Inputs Level 1 [Member]
Assets at fair value on a recurring basis
Temporary cash investments	76.8	144.2
Total	110.9	185.9
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		1.3
Entergy Mississippi [Member] | Fair Value Inputs Level 1 [Member] | Escrow Accounts [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	31.8	41.7
Entergy Mississippi [Member] | Fair Value Inputs Level 1 [Member] | Fixed Transmission Rights (FTRs) [Member] | Fair Value, Measurements, Recurring [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	0.0	0.0
Entergy Mississippi [Member] | Fair Value Inputs Level 1 [Member] | Gas Hedge Contracts Assets [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	2.3
Entergy Mississippi [Member] | Fair Value Inputs Level 2 [Member]
Assets at fair value on a recurring basis
Temporary cash investments	0.0	0.0
Total	0.0	0.0
Entergy Mississippi [Member] | 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		0.0
Entergy Mississippi [Member] | Fair Value Inputs Level 2 [Member] | Escrow Accounts [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	0.0	0.0
Entergy Mississippi [Member] | Fair Value Inputs Level 2 [Member] | Fixed Transmission Rights (FTRs) [Member] | Fair Value, Measurements, Recurring [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	0.0	0.0
Entergy Mississippi [Member] | Fair Value Inputs Level 2 [Member] | Gas Hedge Contracts Assets [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	0.0
Entergy Mississippi [Member] | Fair Value Inputs Level 3 [Member]
Assets at fair value on a recurring basis
Temporary cash investments	0.0	0.0
Total	3.2	2.4
Entergy Mississippi [Member] | 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		0.0
Entergy Mississippi [Member] | Fair Value Inputs Level 3 [Member] | Escrow Accounts [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	0.0	0.0
Entergy Mississippi [Member] | Fair Value Inputs Level 3 [Member] | Fixed Transmission Rights (FTRs) [Member] | Fair Value, Measurements, Recurring [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	3.2	2.4
Entergy Mississippi [Member] | Fair Value Inputs Level 3 [Member] | Gas Hedge Contracts Assets [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	0.0
Entergy Louisiana [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	1,140.7	1,042.3
Entergy Louisiana [Member] | Fair Value, Measurements, Recurring [Member]
Assets at fair value on a recurring basis
Temporary cash investments	163.9	34.8
Total	1,632.5	1,379.2
Entergy Louisiana [Member] | Gas Hedge Contracts [Member] | Fair Value, Measurements, Recurring [Member]
Liabilities at fair value on a recurring basis
Liabilities, Fair Value Disclosure on Recurring Basis		7.0
Entergy Louisiana [Member] | Equity Securities [Member] | Fair Value, Measurements, Recurring [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	13.9	7.1
Entergy Louisiana [Member] | Debt Securities [Member] | Fair Value, Measurements, Recurring [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	424.8	409.9
Entergy Louisiana [Member] | Securitization Recovery Trust Account [Member] | Fair Value, Measurements, Recurring [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	2.8	3.2
Entergy Louisiana [Member] | Escrow Accounts [Member] | Fair Value, Measurements, Recurring [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	305.7	290.4
Entergy Louisiana [Member] | Fixed Transmission Rights (FTRs) [Member] | Fair Value, Measurements, Recurring [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	8.5	8.5
Entergy Louisiana [Member] | Common trust funds valued using Net Asset Value [Domain] | Fair Value, Measurements, Recurring [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	702.0	625.3
Entergy Louisiana [Member] | Gas Hedge Contracts Assets [Member] | Fair Value, Measurements, Recurring [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	10.9
Entergy Louisiana [Member] | Fair Value Inputs Level 1 [Member]
Assets at fair value on a recurring basis
Temporary cash investments	163.9	34.8
Total	629.5	496.6
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		7.0
Entergy Louisiana [Member] | Fair Value Inputs Level 1 [Member] | Equity Securities [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	13.9	7.1
Entergy Louisiana [Member] | Fair Value Inputs Level 1 [Member] | Debt Securities [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	132.3	161.1
Entergy Louisiana [Member] | Fair Value Inputs Level 1 [Member] | Securitization Recovery Trust Account [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	2.8	3.2
Entergy Louisiana [Member] | Fair Value Inputs Level 1 [Member] | Escrow Accounts [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	305.7	290.4
Entergy Louisiana [Member] | Fair Value Inputs Level 1 [Member] | Fixed Transmission Rights (FTRs) [Member] | Fair Value, Measurements, Recurring [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	0.0	0.0
Entergy Louisiana [Member] | Fair Value Inputs Level 1 [Member] | Gas Hedge Contracts Assets [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	10.9
Entergy Louisiana [Member] | Fair Value Inputs Level 2 [Member]
Assets at fair value on a recurring basis
Temporary cash investments	0.0	0.0
Total	292.5	248.8
Entergy Louisiana [Member] | 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		0.0
Entergy Louisiana [Member] | Fair Value Inputs Level 2 [Member] | Equity Securities [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	0.0	0.0
Entergy Louisiana [Member] | Fair Value Inputs Level 2 [Member] | Debt Securities [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	292.5	248.8
Entergy Louisiana [Member] | Fair Value Inputs Level 2 [Member] | Securitization Recovery Trust Account [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	0.0	0.0
Entergy Louisiana [Member] | Fair Value Inputs Level 2 [Member] | Escrow Accounts [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	0.0	0.0
Entergy Louisiana [Member] | Fair Value Inputs Level 2 [Member] | Fixed Transmission Rights (FTRs) [Member] | Fair Value, Measurements, Recurring [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	0.0	0.0
Entergy Louisiana [Member] | Fair Value Inputs Level 2 [Member] | Gas Hedge Contracts Assets [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	0.0
Entergy Louisiana [Member] | Fair Value Inputs Level 3 [Member]
Assets at fair value on a recurring basis
Temporary cash investments	0.0	0.0
Total	8.5	8.5
Entergy Louisiana [Member] | 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		0.0
Entergy Louisiana [Member] | Fair Value Inputs Level 3 [Member] | Equity Securities [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	0.0	0.0
Entergy Louisiana [Member] | Fair Value Inputs Level 3 [Member] | Debt Securities [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	0.0	0.0
Entergy Louisiana [Member] | Fair Value Inputs Level 3 [Member] | Securitization Recovery Trust Account [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	0.0	0.0
Entergy Louisiana [Member] | Fair Value Inputs Level 3 [Member] | Escrow Accounts [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	0.0	0.0
Entergy Louisiana [Member] | Fair Value Inputs Level 3 [Member] | Fixed Transmission Rights (FTRs) [Member] | Fair Value, Measurements, Recurring [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	8.5	8.5
Entergy Louisiana [Member] | Fair Value Inputs Level 3 [Member] | Gas Hedge Contracts Assets [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	0.0
Entergy Arkansas [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	834.7	771.3
Entergy Arkansas [Member] | Fair Value, Measurements, Recurring [Member]
Assets at fair value on a recurring basis
Total	851.3	795.6
Entergy Arkansas [Member] | Equity Securities [Member] | Fair Value, Measurements, Recurring [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	3.6	3.0
Entergy Arkansas [Member] | Debt Securities [Member] | Fair Value, Measurements, Recurring [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	309.3	303.9
Entergy Arkansas [Member] | Securitization Recovery Trust Account [Member] | Fair Value, Measurements, Recurring [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	4.1	4.2
Entergy Arkansas [Member] | Escrow Accounts [Member] | Fair Value, Measurements, Recurring [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	7.1	12.2
Entergy Arkansas [Member] | Fixed Transmission Rights (FTRs) [Member] | Fair Value, Measurements, Recurring [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	5.4	7.9
Entergy Arkansas [Member] | Common trust funds valued using Net Asset Value [Domain] | Fair Value, Measurements, Recurring [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	521.8	464.4
Entergy Arkansas [Member] | Fair Value Inputs Level 1 [Member]
Assets at fair value on a recurring basis
Total	127.3	129.9
Entergy Arkansas [Member] | Fair Value Inputs Level 1 [Member] | Equity Securities [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	3.6	3.0
Entergy Arkansas [Member] | Fair Value Inputs Level 1 [Member] | Debt Securities [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	112.5	110.5
Entergy Arkansas [Member] | Fair Value Inputs Level 1 [Member] | Securitization Recovery Trust Account [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	4.1	4.2
Entergy Arkansas [Member] | Fair Value Inputs Level 1 [Member] | Escrow Accounts [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	7.1	12.2
Entergy Arkansas [Member] | Fair Value Inputs Level 1 [Member] | Fixed Transmission Rights (FTRs) [Member] | Fair Value, Measurements, Recurring [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	0.0	0.0
Entergy Arkansas [Member] | Fair Value Inputs Level 2 [Member]
Assets at fair value on a recurring basis
Total	196.8	193.4
Entergy Arkansas [Member] | Fair Value Inputs Level 2 [Member] | Equity Securities [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	0.0	0.0
Entergy Arkansas [Member] | Fair Value Inputs Level 2 [Member] | Debt Securities [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	196.8	193.4
Entergy Arkansas [Member] | Fair Value Inputs Level 2 [Member] | Securitization Recovery Trust Account [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	0.0	0.0
Entergy Arkansas [Member] | Fair Value Inputs Level 2 [Member] | Escrow Accounts [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	0.0	0.0
Entergy Arkansas [Member] | Fair Value Inputs Level 2 [Member] | Fixed Transmission Rights (FTRs) [Member] | Fair Value, Measurements, Recurring [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	0.0	0.0
Entergy Arkansas [Member] | Fair Value Inputs Level 3 [Member]
Assets at fair value on a recurring basis
Total	5.4	7.9
Entergy Arkansas [Member] | Fair Value Inputs Level 3 [Member] | Equity Securities [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	0.0	0.0
Entergy Arkansas [Member] | Fair Value Inputs Level 3 [Member] | Debt Securities [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	0.0	0.0
Entergy Arkansas [Member] | Fair Value Inputs Level 3 [Member] | Securitization Recovery Trust Account [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	0.0	0.0
Entergy Arkansas [Member] | Fair Value Inputs Level 3 [Member] | Escrow Accounts [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	0.0	0.0
Entergy Arkansas [Member] | Fair Value Inputs Level 3 [Member] | Fixed Transmission Rights (FTRs) [Member] | Fair Value, Measurements, Recurring [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	5.4	7.9
System Energy [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	780.5	701.5
System Energy [Member] | Fair Value, Measurements, Recurring [Member]
Assets at fair value on a recurring basis
Temporary cash investments	245.1	222.0
Total	1,025.6	923.5
System Energy [Member] | Equity Securities [Member] | Fair Value, Measurements, Recurring [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	0.3	1.8
System Energy [Member] | Debt Securities [Member] | Fair Value, Measurements, Recurring [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	306.6	277.8
System Energy [Member] | Common trust funds valued using Net Asset Value [Domain] | Fair Value, Measurements, Recurring [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	473.6	421.9
System Energy [Member] | Fair Value Inputs Level 1 [Member]
Assets at fair value on a recurring basis
Temporary cash investments	245.1	222.0
Total	493.7	442.4
System Energy [Member] | Fair Value Inputs Level 1 [Member] | Equity Securities [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	0.3	1.8
System Energy [Member] | Fair Value Inputs Level 1 [Member] | Debt Securities [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	248.3	218.6
System Energy [Member] | Fair Value Inputs Level 2 [Member]
Assets at fair value on a recurring basis
Temporary cash investments	0.0	0.0
Total	58.3	59.2
System Energy [Member] | Fair Value Inputs Level 2 [Member] | Equity Securities [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	0.0	0.0
System Energy [Member] | Fair Value Inputs Level 2 [Member] | Debt Securities [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	58.3	59.2
System Energy [Member] | Fair Value Inputs Level 3 [Member]
Assets at fair value on a recurring basis
Temporary cash investments	0.0	0.0
Total	0.0	0.0
System Energy [Member] | Fair Value Inputs Level 3 [Member] | Equity Securities [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	0.0	0.0
System Energy [Member] | Fair Value Inputs Level 3 [Member] | Debt Securities [Member]
Assets at fair value on a recurring basis
Available-for-sale Securities	$ 0.0	$ 0.0