Income Taxes (Summary Of Accrued Interest And Penalties Related To Unrecognized Tax Benefits) (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Accrued income tax interest and penalties	$ 48.0	$ 44.0	$ 38.0
Entergy Arkansas [Member]
Accrued income tax interest and penalties	3.1	1.7	1.6
Entergy Louisiana [Member]
Accrued income tax interest and penalties	14.2	17.9	14.1
Entergy Mississippi [Member]
Accrued income tax interest and penalties	1.7	1.2	1.0
Entergy New Orleans [Member]
Accrued income tax interest and penalties	4.7	2.7	2.1
Entergy Texas [Member]
Accrued income tax interest and penalties	1.1	0.9	0.4
System Energy [Member]
Accrued income tax interest and penalties	$ 14.5	$ 13.2	$ 8.5