Asset Retirement Obligations (Difference Between Estimated Incurred Removal Costs And Estimated Removal Costs Recovered In Rates) (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Entergy Arkansas [Member]
Asset Retirement Obligations [Line Items]
Regulatory Assets	$ 138.3	$ 176.9
Entergy Louisiana [Member]
Asset Retirement Obligations [Line Items]
Regulatory Liabilities	(18.8)	(32.4)
Entergy Mississippi [Member]
Asset Retirement Obligations [Line Items]
Regulatory Assets	63.5	91.6
Entergy New Orleans [Member]
Asset Retirement Obligations [Line Items]
Regulatory Assets	49.3	44.8
Entergy Texas [Member]
Asset Retirement Obligations [Line Items]
Regulatory Assets	50.9	55.2
System Energy [Member]
Asset Retirement Obligations [Line Items]
Regulatory Assets	$ 76.4	$ 67.9