Decommissioning Trust Funds (Securities Held) (Details) - USD ($) $ in Millions	Jun. 30, 2022	Dec. 31, 2021
Debt Securities, Available-for-sale [Line Items]
Total	$ 1,692.0	$ 2,177.0
Debt Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Unrealized Loss Position	157.0	12.0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	4.0	65.0
Total	1,692.0	2,177.0
Entergy Arkansas [Member]
Debt Securities, Available-for-sale [Line Items]
Total	484.8	526.3
Entergy Arkansas [Member] | Debt Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Unrealized Loss Position	52.2	4.7
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	0.2	11.4
Total	484.8	526.3
Entergy Louisiana [Member]
Debt Securities, Available-for-sale [Line Items]
Total	733.3	794.2
Entergy Louisiana [Member] | Debt Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Unrealized Loss Position	56.0	3.3
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	3.2	31.3
Total	733.3	794.2
System Energy [Member]
Debt Securities, Available-for-sale [Line Items]
Total	474.3	524.5
System Energy [Member] | Debt Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Unrealized Loss Position	49.2	2.9
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	0.2	11.8
Total	$ 474.3	$ 524.5