Income Taxes (Summary Of Accrued Interest And Penalties Related To Unrecognized Tax Benefits) (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Accrued income tax interest and penalties	$ 27.0	$ 127.0	$ 96.4
Entergy Arkansas [Member]
Accrued income tax interest and penalties	1.3	17.0	15.2
Entergy Louisiana [Member]
Accrued income tax interest and penalties	9.3	22.2	18.0
Entergy Mississippi [Member]
Accrued income tax interest and penalties	0.4	2.8	2.1
Entergy New Orleans [Member]
Accrued income tax interest and penalties	1.8	1.3	0.9
Entergy Texas [Member]
Accrued income tax interest and penalties	1.2	1.0	0.8
System Energy [Member]
Accrued income tax interest and penalties	$ 0.7	$ 23.8	$ 19.0