Retirement And Other Postretirement Benefits (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Defined Benefit Plan, Expected Future Employer Contributions, Remainder of Fiscal Year		$ 416,300		$ 416,300
Defined Benefit Plan, Plan Assets, Contributions by Employer				189,500
Entergy Arkansas [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Defined Benefit Plan, Expected Future Employer Contributions, Remainder of Fiscal Year		73,905		73,905
Defined Benefit Plan, Plan Assets, Contributions by Employer				43,032
Entergy Louisiana [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Defined Benefit Plan, Expected Future Employer Contributions, Remainder of Fiscal Year		74,572		74,572
Defined Benefit Plan, Plan Assets, Contributions by Employer				30,988
Entergy Mississippi [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Defined Benefit Plan, Expected Future Employer Contributions, Remainder of Fiscal Year		15,664		15,664
Defined Benefit Plan, Plan Assets, Contributions by Employer				8,691
Entergy New Orleans [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Defined Benefit Plan, Expected Future Employer Contributions, Remainder of Fiscal Year		6,301		6,301
Defined Benefit Plan, Plan Assets, Contributions by Employer				2,353
Entergy Texas [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Defined Benefit Plan, Expected Future Employer Contributions, Remainder of Fiscal Year		6,901		6,901
Defined Benefit Plan, Plan Assets, Contributions by Employer				2,517
System Energy [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Defined Benefit Plan, Expected Future Employer Contributions, Remainder of Fiscal Year		20,406		20,406
Defined Benefit Plan, Plan Assets, Contributions by Employer				10,635
Subsequent Event [Member] | Entergy Arkansas [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Defined Benefit Plan, Plan Assets, Contributions by Employer	$ 30,873
Subsequent Event [Member] | Entergy Louisiana [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Defined Benefit Plan, Plan Assets, Contributions by Employer	43,584
Subsequent Event [Member] | Entergy Mississippi [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Defined Benefit Plan, Plan Assets, Contributions by Employer	6,973
Subsequent Event [Member] | Entergy New Orleans [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Defined Benefit Plan, Plan Assets, Contributions by Employer	3,948
Subsequent Event [Member] | Entergy Texas [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Defined Benefit Plan, Plan Assets, Contributions by Employer	4,384
Subsequent Event [Member] | System Energy [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Defined Benefit Plan, Plan Assets, Contributions by Employer	$ 9,771
Non Qualified Pension Plans [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Net other postretirement benefit cost		4,500	$ 4,600	13,600	$ 16,300
Defined Benefit Plan, Benefit Obligation, Payment for Settlement			955		4,600
Non Qualified Pension Plans [Member] | Entergy Arkansas [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Net other postretirement benefit cost		83	67	249	211
Non Qualified Pension Plans [Member] | Entergy Louisiana [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Net other postretirement benefit cost		37	38	111	122
Non Qualified Pension Plans [Member] | Entergy Mississippi [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Net other postretirement benefit cost		90	69	270	257
Defined Benefit Plan, Plan Assets, Payment for Settlement					40
Non Qualified Pension Plans [Member] | Entergy New Orleans [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Net other postretirement benefit cost		7	5	21	16
Non Qualified Pension Plans [Member] | Entergy Texas [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Net other postretirement benefit cost		$ 118	$ 119	354	$ 365
Qualified Pension Plans [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Defined Benefit Plan, Benefit Obligation, Payment for Settlement				32,400
Qualified Pension Plans [Member] | Entergy Arkansas [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Defined Benefit Plan, Benefit Obligation, Payment for Settlement				19,700
Qualified Pension Plans [Member] | Entergy Louisiana [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Defined Benefit Plan, Benefit Obligation, Payment for Settlement				6,500
Qualified Pension Plans [Member] | Entergy Mississippi [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Defined Benefit Plan, Benefit Obligation, Payment for Settlement				2,300
Qualified Pension Plans [Member] | Entergy Texas [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Defined Benefit Plan, Benefit Obligation, Payment for Settlement				$ 3,900