Income Taxes (Summary Of Accrued Interest And Penalties Related To Unrecognized Tax Benefits) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Accrued income tax interest and penalties	$ 127.0	$ 96.4	$ 146.0
Entergy Arkansas [Member]
Accrued income tax interest and penalties	17.0	15.2	21.8
Entergy Gulf States Louisiana [Member]
Accrued income tax interest and penalties	21.0	17.0	33.1
Entergy Louisiana [Member]
Accrued income tax interest and penalties	1.2	1.0	0.9
Entergy Mississippi [Member]
Accrued income tax interest and penalties	2.8	2.1	2.4
Entergy New Orleans [Member]
Accrued income tax interest and penalties	1.3	0.9	0.1
Entergy Texas [Member]
Accrued income tax interest and penalties	1.0	0.8	0.7
System Energy [Member]
Accrued income tax interest and penalties	$ 23.8	$ 19.0	$ 33.2