Property, Plant, And Equipment (Narrative) (Details) - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Construction expenditures in accounts payable	$ 280.0	$ 368.0
Entergy Arkansas [Member]
Construction expenditures in accounts payable	30.3	58.8
Entergy Louisiana [Member]
Construction expenditures in accounts payable	113.5	160.4
Entergy Mississippi [Member]
Construction expenditures in accounts payable	15.2	17.1
Entergy New Orleans [Member]
Construction expenditures in accounts payable	4.8	2.5
Entergy Texas [Member]
Construction expenditures in accounts payable	7.1	32.8
System Energy [Member]
Construction expenditures in accounts payable	$ 53.0	$ 33.9