Income Taxes Income Taxes (Reduction to Regulatory Liability Due to Return of Unprotected Excess ADIT (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Reduction to regulatory liability due to return of unprotected excess accumulated deferred income taxes	$ 14	$ 15	$ 54	$ 45
Valuation Allowance - Reduction	9
Entergy Arkansas [Member]
Reduction to regulatory liability due to return of unprotected excess accumulated deferred income taxes	0		8	12
Increase in regulatory liability due to return of unprotected excess accumulated deferred income taxes		(1)
Entergy Louisiana [Member]
Reduction to regulatory liability due to return of unprotected excess accumulated deferred income taxes	8	8	15	16
Entergy New Orleans [Member]
Reduction to regulatory liability due to return of unprotected excess accumulated deferred income taxes	0	2	0	5
Entergy Texas [Member]
Reduction to regulatory liability due to return of unprotected excess accumulated deferred income taxes	6	6	13	12
System Energy [Member]
Reduction to regulatory liability due to return of unprotected excess accumulated deferred income taxes	$ 0	$ 0	$ 18	$ 0