Property, Plant, And Equipment (Narrative) (Details) - USD ($) $ in Millions	Jun. 30, 2015	Dec. 31, 2014
Construction expenditures in accounts payable	$ 145.0	$ 209.0
Entergy Arkansas [Member]
Construction expenditures in accounts payable	13.8	37.3
Entergy Gulf States Louisiana [Member]
Construction expenditures in accounts payable	33.4	23.4
Entergy Louisiana [Member]
Construction expenditures in accounts payable	16.9	48.0
Entergy Mississippi [Member]
Construction expenditures in accounts payable	1.0	7.8
Entergy New Orleans [Member]
Construction expenditures in accounts payable	0.2	0.9
Entergy Texas [Member]
Construction expenditures in accounts payable	13.5	24.1
System Energy [Member]
Construction expenditures in accounts payable	$ 15.4	$ 7.7