Property, Plant, And Equipment (Narrative) (Details) - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017
Construction expenditures in accounts payable	$ 280.0	$ 368.0
Entergy Arkansas [Member]
Construction expenditures in accounts payable	39.1	58.8
Entergy Louisiana [Member]
Construction expenditures in accounts payable	119.4	160.4
Entergy Mississippi [Member]
Construction expenditures in accounts payable	7.5	17.1
Entergy New Orleans [Member]
Construction expenditures in accounts payable	5.6	2.5
Entergy Texas [Member]
Construction expenditures in accounts payable	14.8	32.8
System Energy [Member]
Construction expenditures in accounts payable	$ 41.9	$ 33.9