Revolving Credit Facilities, Lines Of Credit, Short-Term Borrowings, And Long-Term Debt (Notes Payable By Variable Interest Entities) (Details) - USD ($) $ in Millions	Sep. 30, 2018	Mar. 31, 2018
Three Point Six Five Percent Series L Notes Due July Two Thousand Twenty One [Member] | Entergy Arkansas VIE [Member]
Notes payable by variable interest entities
Stated interest rate (percentage)	3.65%
Amount	$ 90
Three Point One Seven Percent Series M Notes Due December Two Thousand Twenty Three [Member] | Entergy Arkansas VIE [Member]
Notes payable by variable interest entities
Stated interest rate (percentage)	3.17%
Amount	$ 40
Three Point Three Eight Percent Series R Notes Due August Two Thousand Twenty [Member] | Entergy Louisiana River Bend VIE [Member]
Notes payable by variable interest entities
Stated interest rate (percentage)	3.38%
Amount	$ 70
Three Point Nine Two Percent Series H Dues February Two Thousand Twenty One [Member] | Entergy Louisiana Waterford VIE [Member]
Notes payable by variable interest entities
Stated interest rate (percentage)	3.92%
Amount	$ 40
Three Point Two Two Percent Series I Notes Due December Two Thousand Twenty Three [Domain] | Entergy Louisiana Waterford VIE [Member]
Notes payable by variable interest entities
Stated interest rate (percentage)	3.22%
Amount	$ 20
Three Point Seven Eight Percent Series I Notes Due October Two Thousand Eighteen [Member] | System Energy VIE [Member]
Notes payable by variable interest entities
Stated interest rate (percentage)	3.78%
Amount	$ 85
Three Point Four Two Percent Series J Notes Due April Two Thousand Twenty One [Member] | System Energy VIE [Member]
Notes payable by variable interest entities
Stated interest rate (percentage)	3.42%	3.42%
Amount	$ 100