Revolving Credit Facilities, Lines Of Credit, Short-Term Borrowings, And Long-Term Debt Revolving Credit Facilities, Lines Of Credit, Short-Term Borrowings, And Long-Term Debt (Uncommitted Standby Letter of Credit Facilities to Support MISO Obligations) (Details) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Letters of Credit Outstanding, Amount	$ 19.0
Entergy Arkansas [Member]
Letters of Credit Outstanding, Amount	0.3	$ 0.3
Entergy Mississippi [Member]
Letters of Credit Outstanding, Amount	0.1	$ 0.1
Credit Facility Of Twenty Five Million [Member] | Entergy Arkansas [Member]
Uncommitted Credit Facility	$ 25.0
Letter of Credit Fee, Percentage	0.70%
Letters of Credit Outstanding, Amount	$ 1.0
Credit Facility of Fifty Million [Member] | Entergy Texas [Member]
Uncommitted Credit Facility	$ 50.0
Letter of Credit Fee, Percentage	0.70%
Letters of Credit Outstanding, Amount	$ 22.3
Credit Facility of Forty Million [Member] | Entergy Mississippi [Member]
Uncommitted Credit Facility	$ 40.0
Letter of Credit Fee, Percentage	0.70%
Letters of Credit Outstanding, Amount	$ 7.8
Credit Facility of Fifteen Million [Member] | Entergy New Orleans [Member]
Uncommitted Credit Facility	$ 15.0
Letter of Credit Fee, Percentage	0.75%
Letters of Credit Outstanding, Amount	$ 5.6
Credit Facility Of One Hundred Twenty Five Million [Member] | Entergy Louisiana [Member]
Uncommitted Credit Facility	$ 125.0
Letter of Credit Fee, Percentage	0.70%
Letters of Credit Outstanding, Amount	$ 36.8