Transactions With Affiliates (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Entergy Arkansas [Member]
Intercompany revenues	$ 49.4	$ 127.9	$ 131.2
Intercompany operating expenses	467.4	508.5	596.6
Entergy Louisiana [Member]
Intercompany revenues	376.6	420.2	440.2
Intercompany operating expenses	670.8	929.4	1,027.6
Intercompany interest and investment income	127.7	133.6	117.9
Entergy Mississippi [Member]
Intercompany revenues	2.9	86.0	169.8
Intercompany operating expenses	256.5	331.8	367.6
Intercompany interest and investment income	0.1	0.0	0.0
Entergy New Orleans [Member]
Intercompany revenues	30.3	66.1	80.1
Intercompany operating expenses	276.7	278.4	249.5
Entergy Texas [Member]
Intercompany revenues	180.2	259.1	316.1
Intercompany operating expenses	343.7	413.7	445.3
System Energy [Member]
Intercompany revenues	548.3	632.4	664.4
Intercompany operating expenses	146.0	155.1	156.7
Intercompany interest and investment income	$ 0.1	$ 0.0	$ 0.0