Decommissioning Trust Funds (Securities Held) (Details) - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021
Debt Securities, Available-for-sale [Line Items]
Total	$ 2,070.0	$ 2,177.0
Debt Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Unrealized Loss Position	99.0	12.0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	15.0	65.0
Total	2,070.0	2,177.0
Entergy Arkansas [Member]
Debt Securities, Available-for-sale [Line Items]
Total	509.3	526.3
Entergy Arkansas [Member] | Debt Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Unrealized Loss Position	28.3	4.7
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	1.4	11.4
Total	509.3	526.3
Entergy Louisiana [Member]
Debt Securities, Available-for-sale [Line Items]
Total	747.5	794.2
Entergy Louisiana [Member] | Debt Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Unrealized Loss Position	30.2	3.3
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	9.7	31.3
Total	747.5	794.2
System Energy [Member]
Debt Securities, Available-for-sale [Line Items]
Total	499.6	524.5
System Energy [Member] | Debt Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Unrealized Loss Position	27.6	2.9
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	1.9	11.8
Total	$ 499.6	$ 524.5