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Risk Management and Fair Values (Assets And Liabilities At Fair Value On A Recurring Basis) (Details) - USD ($)
$ in Thousands
 3 Months Ended 6 Months Ended
Jun. 30, 2021
Jun. 30, 2020
Jun. 30, 2021
Jun. 30, 2020
Dec. 31, 2020
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
Cash Equivalents, at Carrying Value $ 529,616   $ 529,616   $ 1,630,248
Assets at fair value on a recurring basis          
Restricted Cash and Cash Equivalents, Current 33,000   33,000   42,000
Replacement Reserve Escrow 88,000   88,000   148,000
Equity Securities, FV-NI 53,000   53,000   1,533,000
Debt Securities 2,038,000   2,038,000   2,617,000
Liabilities at fair value on a recurring basis          
Assets, Fair Value Disclosure 5,920,000   5,920,000   9,122,000
Issuance of Financial Transmission Rights 0 $ 0 0 $ 0  
Fixed Transmission Rights (FTRs) [Member]          
Liabilities at fair value on a recurring basis          
Issuance of Financial Transmission Rights 12,000 23,000 12,000 23,000  
Gas Hedge Contracts [Member]          
Liabilities at fair value on a recurring basis          
Liabilities, Fair Value Disclosure on Recurring Basis         7,000
Common trust funds valued using Net Asset Value [Domain]          
Assets at fair value on a recurring basis          
Available-for-sale Securities 3,148,000   3,148,000   3,103,000
Power Contracts Assets [Member]          
Assets at fair value on a recurring basis          
Derivative Asset         38,000
Gas Hedge Contracts Assets [Member]          
Assets at fair value on a recurring basis          
Derivative Asset 15,000   15,000   2,000
Fixed Transmission Rights (FTRs) [Member]          
Assets at fair value on a recurring basis          
Derivative Asset 15,000   15,000   9,000
Fair Value Inputs Level 1 [Member]          
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
Cash Equivalents, at Carrying Value 530,000   530,000   1,630,000
Assets at fair value on a recurring basis          
Restricted Cash and Cash Equivalents, Current 33,000   33,000   42,000
Replacement Reserve Escrow 88,000   88,000   148,000
Equity Securities, FV-NI 53,000   53,000   1,533,000
Debt Securities 686,000   686,000   919,000
Liabilities at fair value on a recurring basis          
Assets, Fair Value Disclosure 1,405,000   1,405,000   4,273,000
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         6,000
Fair Value Inputs Level 1 [Member] | Power Contracts Assets [Member]          
Assets at fair value on a recurring basis          
Derivative Asset         0
Fair Value Inputs Level 1 [Member] | Gas Hedge Contracts Assets [Member]          
Assets at fair value on a recurring basis          
Derivative Asset 15,000   15,000   1,000
Fair Value Inputs Level 1 [Member] | Fixed Transmission Rights (FTRs) [Member]          
Assets at fair value on a recurring basis          
Derivative Asset 0   0   0
Fair Value, Inputs, Level 2 [Member]          
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
Cash Equivalents, at Carrying Value 0   0   0
Assets at fair value on a recurring basis          
Restricted Cash and Cash Equivalents, Current 0   0   0
Replacement Reserve Escrow 0   0   0
Equity Securities, FV-NI 0   0   0
Debt Securities 1,352,000   1,352,000   1,698,000
Liabilities at fair value on a recurring basis          
Assets, Fair Value Disclosure 1,352,000   1,352,000   1,699,000
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         1,000
Fair Value, Inputs, Level 2 [Member] | Power Contracts Assets [Member]          
Assets at fair value on a recurring basis          
Derivative Asset         0
Fair Value, Inputs, Level 2 [Member] | Gas Hedge Contracts Assets [Member]          
Assets at fair value on a recurring basis          
Derivative Asset 0   0   1,000
Fair Value, Inputs, Level 2 [Member] | Fixed Transmission Rights (FTRs) [Member]          
Assets at fair value on a recurring basis          
Derivative Asset 0   0   0
Fair Value, Inputs, Level 3 [Member]          
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
Cash Equivalents, at Carrying Value 0   0   0
Assets at fair value on a recurring basis          
Restricted Cash and Cash Equivalents, Current 0   0   0
Replacement Reserve Escrow 0   0   0
Equity Securities, FV-NI 0   0   0
Debt Securities 0   0   0
Liabilities at fair value on a recurring basis          
Assets, Fair Value Disclosure 15,000   15,000   47,000
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
Fair Value, Inputs, Level 3 [Member] | Power Contracts Assets [Member]          
Assets at fair value on a recurring basis          
Derivative Asset         38,000
Fair Value, Inputs, Level 3 [Member] | Gas Hedge Contracts Assets [Member]          
Assets at fair value on a recurring basis          
Derivative Asset 0   0   0
Fair Value, Inputs, Level 3 [Member] | Fixed Transmission Rights (FTRs) [Member]          
Assets at fair value on a recurring basis          
Derivative Asset 15,000   15,000   9,000
Entergy New Orleans [Member]          
Assets at fair value on a recurring basis          
Restricted Cash and Cash Equivalents, Current 2,678   2,678   3,364
Replacement Reserve Escrow 38,800   38,800   83,000
Liabilities at fair value on a recurring basis          
Assets, Fair Value Disclosure 42,200   42,200   86,500
Entergy New Orleans [Member] | Fixed Transmission Rights (FTRs) [Member]          
Liabilities at fair value on a recurring basis          
Issuance of Financial Transmission Rights 400 (100) 400 (100)  
Entergy New Orleans [Member] | Gas Hedge Contracts [Member]          
Liabilities at fair value on a recurring basis          
Liabilities, Fair Value Disclosure on Recurring Basis         300
Entergy New Orleans [Member] | Gas Hedge Contracts Assets [Member]          
Assets at fair value on a recurring basis          
Derivative Asset 100   100    
Entergy New Orleans [Member] | Fixed Transmission Rights (FTRs) [Member]          
Assets at fair value on a recurring basis          
Derivative Asset 600   600   100
Entergy New Orleans [Member] | Fair Value Inputs Level 1 [Member]          
Assets at fair value on a recurring basis          
Restricted Cash and Cash Equivalents, Current 2,700   2,700   3,400
Replacement Reserve Escrow 38,800   38,800   83,000
Liabilities at fair value on a recurring basis          
Assets, Fair Value Disclosure 41,600   41,600   86,400
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         300
Entergy New Orleans [Member] | Fair Value Inputs Level 1 [Member] | Gas Hedge Contracts Assets [Member]          
Assets at fair value on a recurring basis          
Derivative Asset 100   100    
Entergy New Orleans [Member] | Fair Value Inputs Level 1 [Member] | Fixed Transmission Rights (FTRs) [Member]          
Assets at fair value on a recurring basis          
Derivative Asset 0   0   0
Entergy New Orleans [Member] | Fair Value, Inputs, Level 2 [Member]          
Assets at fair value on a recurring basis          
Restricted Cash and Cash Equivalents, Current 0   0   0
Replacement Reserve Escrow 0   0   0
Liabilities at fair value on a recurring basis          
Assets, Fair Value Disclosure 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
Entergy New Orleans [Member] | Fair Value, Inputs, Level 2 [Member] | Gas Hedge Contracts Assets [Member]          
Assets at fair value on a recurring basis          
Derivative Asset 0   0    
Entergy New Orleans [Member] | Fair Value, Inputs, Level 2 [Member] | Fixed Transmission Rights (FTRs) [Member]          
Assets at fair value on a recurring basis          
Derivative Asset 0   0   0
Entergy New Orleans [Member] | Fair Value, Inputs, Level 3 [Member]          
Assets at fair value on a recurring basis          
Restricted Cash and Cash Equivalents, Current 0   0   0
Replacement Reserve Escrow 0   0   0
Liabilities at fair value on a recurring basis          
Assets, Fair Value Disclosure 600   600   100
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
Entergy New Orleans [Member] | Fair Value, Inputs, Level 3 [Member] | Gas Hedge Contracts Assets [Member]          
Assets at fair value on a recurring basis          
Derivative Asset 0   0    
Entergy New Orleans [Member] | Fair Value, Inputs, Level 3 [Member] | Fixed Transmission Rights (FTRs) [Member]          
Assets at fair value on a recurring basis          
Derivative Asset 600   600   100
Entergy Mississippi [Member]          
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
Cash Equivalents, at Carrying Value 0   0   7
Assets at fair value on a recurring basis          
Replacement Reserve Escrow 48,900   48,900   64,600
Liabilities at fair value on a recurring basis          
Assets, Fair Value Disclosure 60,500   60,500   65,200
Entergy Mississippi [Member] | Fixed Transmission Rights (FTRs) [Member]          
Liabilities at fair value on a recurring basis          
Issuance of Financial Transmission Rights 1,700 1,400 1,700 1,400  
Entergy Mississippi [Member] | Gas Hedge Contracts [Member]          
Liabilities at fair value on a recurring basis          
Liabilities, Fair Value Disclosure on Recurring Basis         5,000
Entergy Mississippi [Member] | Gas Hedge Contracts Assets [Member]          
Assets at fair value on a recurring basis          
Derivative Asset 9,600   9,600    
Entergy Mississippi [Member] | Fixed Transmission Rights (FTRs) [Member]          
Assets at fair value on a recurring basis          
Derivative Asset 2,000   2,000   600
Entergy Mississippi [Member] | Fair Value Inputs Level 1 [Member]          
Assets at fair value on a recurring basis          
Replacement Reserve Escrow 48,900   48,900   64,600
Liabilities at fair value on a recurring basis          
Assets, Fair Value Disclosure 58,500   58,500   64,600
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         5,000
Entergy Mississippi [Member] | Fair Value Inputs Level 1 [Member] | Gas Hedge Contracts Assets [Member]          
Assets at fair value on a recurring basis          
Derivative Asset 9,600   9,600    
Entergy Mississippi [Member] | Fair Value Inputs Level 1 [Member] | Fixed Transmission Rights (FTRs) [Member]          
Assets at fair value on a recurring basis          
Derivative Asset 0   0   0
Entergy Mississippi [Member] | Fair Value, Inputs, Level 2 [Member]          
Assets at fair value on a recurring basis          
Replacement Reserve Escrow 0   0   0
Liabilities at fair value on a recurring basis          
Assets, Fair Value Disclosure 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
Entergy Mississippi [Member] | Fair Value, Inputs, Level 2 [Member] | Gas Hedge Contracts Assets [Member]          
Assets at fair value on a recurring basis          
Derivative Asset 0   0    
Entergy Mississippi [Member] | Fair Value, Inputs, Level 2 [Member] | Fixed Transmission Rights (FTRs) [Member]          
Assets at fair value on a recurring basis          
Derivative Asset 0   0   0
Entergy Mississippi [Member] | Fair Value, Inputs, Level 3 [Member]          
Assets at fair value on a recurring basis          
Replacement Reserve Escrow 0   0   0
Liabilities at fair value on a recurring basis          
Assets, Fair Value Disclosure 2,000   2,000   600
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
Entergy Mississippi [Member] | Fair Value, Inputs, Level 3 [Member] | Gas Hedge Contracts Assets [Member]          
Assets at fair value on a recurring basis          
Derivative Asset 0   0    
Entergy Mississippi [Member] | Fair Value, Inputs, Level 3 [Member] | Fixed Transmission Rights (FTRs) [Member]          
Assets at fair value on a recurring basis          
Derivative Asset 2,000   2,000   600
Entergy Louisiana [Member]          
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
Cash Equivalents, at Carrying Value 206,643   206,643   726,717
Assets at fair value on a recurring basis          
Restricted Cash and Cash Equivalents, Current 3,700   3,700   2,700
Equity Securities, FV-NI 19,600   19,600   8,700
Debt Securities 697,500   697,500   632,200
Liabilities at fair value on a recurring basis          
Assets, Fair Value Disclosure 2,206,000   2,206,000   2,528,900
Entergy Louisiana [Member] | Fixed Transmission Rights (FTRs) [Member]          
Liabilities at fair value on a recurring basis          
Issuance of Financial Transmission Rights 4,100 13,200 4,100 13,200  
Entergy Louisiana [Member] | Gas Hedge Contracts [Member]          
Liabilities at fair value on a recurring basis          
Liabilities, Fair Value Disclosure on Recurring Basis         1,600
Entergy Louisiana [Member] | Common trust funds valued using Net Asset Value [Domain]          
Assets at fair value on a recurring basis          
Available-for-sale Securities 1,268,400   1,268,400   1,153,100
Entergy Louisiana [Member] | Gas Hedge Contracts Assets [Member]          
Assets at fair value on a recurring basis          
Derivative Asset 5,400   5,400   1,300
Entergy Louisiana [Member] | Fixed Transmission Rights (FTRs) [Member]          
Assets at fair value on a recurring basis          
Derivative Asset 4,800   4,800   4,200
Entergy Louisiana [Member] | Fair Value Inputs Level 1 [Member]          
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
Cash Equivalents, at Carrying Value 206,600   206,600   726,700
Assets at fair value on a recurring basis          
Restricted Cash and Cash Equivalents, Current 3,700   3,700   2,700
Equity Securities, FV-NI 19,600   19,600   8,700
Debt Securities 213,200   213,200   172,400
Liabilities at fair value on a recurring basis          
Assets, Fair Value Disclosure 448,100   448,100   911,300
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         300
Entergy Louisiana [Member] | Fair Value Inputs Level 1 [Member] | Gas Hedge Contracts Assets [Member]          
Assets at fair value on a recurring basis          
Derivative Asset 5,000   5,000   800
Entergy Louisiana [Member] | Fair Value Inputs Level 1 [Member] | Fixed Transmission Rights (FTRs) [Member]          
Assets at fair value on a recurring basis          
Derivative Asset 0   0   0
Entergy Louisiana [Member] | Fair Value, Inputs, Level 2 [Member]          
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
Cash Equivalents, at Carrying Value 0   0   0
Assets at fair value on a recurring basis          
Restricted Cash and Cash Equivalents, Current 0   0   0
Equity Securities, FV-NI 0   0   0
Debt Securities 484,300   484,300   459,800
Liabilities at fair value on a recurring basis          
Assets, Fair Value Disclosure 484,700   484,700   460,300
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         1,300
Entergy Louisiana [Member] | Fair Value, Inputs, Level 2 [Member] | Gas Hedge Contracts Assets [Member]          
Assets at fair value on a recurring basis          
Derivative Asset 400   400   500
Entergy Louisiana [Member] | Fair Value, Inputs, Level 2 [Member] | Fixed Transmission Rights (FTRs) [Member]          
Assets at fair value on a recurring basis          
Derivative Asset 0   0   0
Entergy Louisiana [Member] | Fair Value, Inputs, Level 3 [Member]          
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
Cash Equivalents, at Carrying Value 0   0   0
Assets at fair value on a recurring basis          
Restricted Cash and Cash Equivalents, Current 0   0   0
Equity Securities, FV-NI 0   0   0
Debt Securities 0   0   0
Liabilities at fair value on a recurring basis          
Assets, Fair Value Disclosure 4,800   4,800   4,200
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
Entergy Louisiana [Member] | Fair Value, Inputs, Level 3 [Member] | Gas Hedge Contracts Assets [Member]          
Assets at fair value on a recurring basis          
Derivative Asset 0   0   0
Entergy Louisiana [Member] | Fair Value, Inputs, Level 3 [Member] | Fixed Transmission Rights (FTRs) [Member]          
Assets at fair value on a recurring basis          
Derivative Asset 4,800   4,800   4,200
Entergy Arkansas [Member]          
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
Cash Equivalents, at Carrying Value 16,244   16,244   168,020
Assets at fair value on a recurring basis          
Equity Securities, FV-NI 12,700   12,700   1,300
Debt Securities 472,500   472,500   447,900
Liabilities at fair value on a recurring basis          
Assets, Fair Value Disclosure 1,396,700   1,396,700   1,444,600
Entergy Arkansas [Member] | Fixed Transmission Rights (FTRs) [Member]          
Liabilities at fair value on a recurring basis          
Issuance of Financial Transmission Rights 2,800 6,500 2,800 6,500  
Entergy Arkansas [Member] | Common trust funds valued using Net Asset Value [Domain]          
Assets at fair value on a recurring basis          
Available-for-sale Securities 891,500   891,500   824,700
Entergy Arkansas [Member] | Fixed Transmission Rights (FTRs) [Member]          
Assets at fair value on a recurring basis          
Derivative Asset 3,800   3,800   2,700
Entergy Arkansas [Member] | Fair Value Inputs Level 1 [Member]          
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
Cash Equivalents, at Carrying Value 16,200   16,200   168,000
Assets at fair value on a recurring basis          
Equity Securities, FV-NI 12,700   12,700   1,300
Debt Securities 99,200   99,200   98,200
Liabilities at fair value on a recurring basis          
Assets, Fair Value Disclosure 128,100   128,100   267,500
Entergy Arkansas [Member] | Fair Value Inputs Level 1 [Member] | Fixed Transmission Rights (FTRs) [Member]          
Assets at fair value on a recurring basis          
Derivative Asset 0   0   0
Entergy Arkansas [Member] | Fair Value, Inputs, Level 2 [Member]          
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
Cash Equivalents, at Carrying Value 0   0   0
Assets at fair value on a recurring basis          
Equity Securities, FV-NI 0   0   0
Debt Securities 373,300   373,300   349,700
Liabilities at fair value on a recurring basis          
Assets, Fair Value Disclosure 373,300   373,300   349,700
Entergy Arkansas [Member] | Fair Value, Inputs, Level 2 [Member] | Fixed Transmission Rights (FTRs) [Member]          
Assets at fair value on a recurring basis          
Derivative Asset 0   0   0
Entergy Arkansas [Member] | Fair Value, Inputs, Level 3 [Member]          
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
Cash Equivalents, at Carrying Value 0   0   0
Assets at fair value on a recurring basis          
Equity Securities, FV-NI 0   0   0
Debt Securities 0   0   0
Liabilities at fair value on a recurring basis          
Assets, Fair Value Disclosure 3,800   3,800   2,700
Entergy Arkansas [Member] | Fair Value, Inputs, Level 3 [Member] | Fixed Transmission Rights (FTRs) [Member]          
Assets at fair value on a recurring basis          
Derivative Asset 3,800   3,800   2,700
Entergy Texas [Member]          
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
Cash Equivalents, at Carrying Value 0   0   248,570
Assets at fair value on a recurring basis          
Restricted Cash and Cash Equivalents, Current 26,278   26,278   36,233
Liabilities at fair value on a recurring basis          
Assets, Fair Value Disclosure 30,100   30,100   286,400
Entergy Texas [Member] | Fixed Transmission Rights (FTRs) [Member]          
Liabilities at fair value on a recurring basis          
Issuance of Financial Transmission Rights 2,700 $ 2,400 2,700 $ 2,400  
Entergy Texas [Member] | Fixed Transmission Rights (FTRs) [Member]          
Assets at fair value on a recurring basis          
Derivative Asset 3,800   3,800   1,600
Entergy Texas [Member] | Fair Value Inputs Level 1 [Member]          
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
Cash Equivalents, at Carrying Value         248,600
Assets at fair value on a recurring basis          
Restricted Cash and Cash Equivalents, Current 26,300   26,300   36,200
Liabilities at fair value on a recurring basis          
Assets, Fair Value Disclosure 26,300   26,300   284,800
Entergy Texas [Member] | Fair Value Inputs Level 1 [Member] | Fixed Transmission Rights (FTRs) [Member]          
Assets at fair value on a recurring basis          
Derivative Asset 0   0   0
Entergy Texas [Member] | Fair Value, Inputs, Level 2 [Member]          
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
Cash Equivalents, at Carrying Value         0
Assets at fair value on a recurring basis          
Restricted Cash and Cash Equivalents, Current 0   0   0
Liabilities at fair value on a recurring basis          
Assets, Fair Value Disclosure 0   0   0
Entergy Texas [Member] | Fair Value, Inputs, Level 2 [Member] | Fixed Transmission Rights (FTRs) [Member]          
Assets at fair value on a recurring basis          
Derivative Asset 0   0   0
Entergy Texas [Member] | Fair Value, Inputs, Level 3 [Member]          
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
Cash Equivalents, at Carrying Value         0
Assets at fair value on a recurring basis          
Restricted Cash and Cash Equivalents, Current 0   0   0
Liabilities at fair value on a recurring basis          
Assets, Fair Value Disclosure 3,800   3,800   1,600
Entergy Texas [Member] | Fair Value, Inputs, Level 3 [Member] | Fixed Transmission Rights (FTRs) [Member]          
Assets at fair value on a recurring basis          
Derivative Asset 3,800   3,800   1,600
System Energy [Member]          
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
Cash Equivalents, at Carrying Value 119,083   119,083   216,383
Assets at fair value on a recurring basis          
Equity Securities, FV-NI 6,000   6,000   3,800
Debt Securities 467,800   467,800   427,700
Liabilities at fair value on a recurring basis          
Assets, Fair Value Disclosure 1,431,600   1,431,600   1,432,300
System Energy [Member] | Common trust funds valued using Net Asset Value [Domain]          
Assets at fair value on a recurring basis          
Available-for-sale Securities 838,700   838,700   784,400
System Energy [Member] | Fair Value Inputs Level 1 [Member]          
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
Cash Equivalents, at Carrying Value 119,100   119,100   216,400
Assets at fair value on a recurring basis          
Equity Securities, FV-NI 6,000   6,000   3,800
Debt Securities 207,300   207,300   177,300
Liabilities at fair value on a recurring basis          
Assets, Fair Value Disclosure 332,400   332,400   397,500
System Energy [Member] | Fair Value, Inputs, Level 2 [Member]          
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
Cash Equivalents, at Carrying Value 0   0   0
Assets at fair value on a recurring basis          
Equity Securities, FV-NI 0   0   0
Debt Securities 260,500   260,500   250,400
Liabilities at fair value on a recurring basis          
Assets, Fair Value Disclosure 260,500   260,500   250,400
System Energy [Member] | Fair Value, Inputs, Level 3 [Member]          
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
Cash Equivalents, at Carrying Value 0   0   0
Assets at fair value on a recurring basis          
Equity Securities, FV-NI 0   0   0
Debt Securities 0   0   0
Liabilities at fair value on a recurring basis          
Assets, Fair Value Disclosure $ 0   $ 0   $ 0