Revolving Credit Facilities, Lines Of Credit, Short-Term Borrowings, And Long-Term Debt (Short-Term Borrowings And The Outstanding Short-Term Borrowings) (Details) $ in Millions	Mar. 31, 2018 USD ($)
Entergy Arkansas [Member]
Short-term borrowings and the outstanding short-term borrowings
Authorized	$ 250
Borrowings	124
Entergy Louisiana [Member]
Short-term borrowings and the outstanding short-term borrowings
Authorized	450
Borrowings	0
Entergy Mississippi [Member]
Short-term borrowings and the outstanding short-term borrowings
Authorized	175
Borrowings	75
Entergy New Orleans [Member]
Short-term borrowings and the outstanding short-term borrowings
Authorized	150
Borrowings	0
Entergy Texas [Member]
Short-term borrowings and the outstanding short-term borrowings
Authorized	200
Borrowings	0
System Energy [Member]
Short-term borrowings and the outstanding short-term borrowings
Authorized	200
Borrowings	$ 0