Property, Plant, And Equipment (Narrative) (Details) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Construction expenditures in accounts payable	$ 198.0	$ 253.0
Entergy Arkansas [Member]
Construction expenditures in accounts payable	47.8	40.9
Entergy Louisiana [Member]
Construction expenditures in accounts payable	55.1	114.8
Entergy Mississippi [Member]
Construction expenditures in accounts payable	5.3	11.5
Entergy New Orleans [Member]
Construction expenditures in accounts payable	1.1	2.3
Entergy Texas [Member]
Construction expenditures in accounts payable	15.2	9.3
System Energy [Member]
Construction expenditures in accounts payable	$ 28.1	$ 6.2