Leases (Rent Expenses) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Rent Expense	$ 59.0	$ 63.7	$ 69.9
Entergy Arkansas [Member]
Rent Expense	12.0	12.0	12.6
Entergy Gulf States Louisiana [Member]
Rent Expense	10.9	10.9	11.9
Entergy Louisiana [Member]
Rent Expense	9.8	10.1	11.2
Entergy Mississippi [Member]
Rent Expense	4.3	4.6	5.5
Entergy New Orleans [Member]
Rent Expense	1.2	1.3	1.5
Entergy Texas [Member]
Rent Expense	3.8	4.1	6.4
System Energy [Member]
Rent Expense	$ 2.0	$ 2.5	$ 1.5