Decommissioning Trust Funds (Schedule of Available-for-Sale Securities Reconciliation) (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2025	Dec. 31, 2024
Debt Securities, Available-for-Sale [Line Items]
Debt Securities, Available-for-Sale	$ 2,091.0	$ 2,047.0
Debt Securities, Available-for-Sale, Unrealized Gain	15.0	7.0
Debt Securities, Available-for-Sale, Unrealized Loss	62.0	80.0
Entergy Arkansas [Member]
Debt Securities, Available-for-Sale [Line Items]
Debt Securities, Available-for-Sale	590.1	579.0
Debt Securities, Available-for-Sale, Unrealized Gain	4.0	1.2
Debt Securities, Available-for-Sale, Unrealized Loss	18.1	25.8
Entergy Louisiana [Member]
Debt Securities, Available-for-Sale [Line Items]
Debt Securities, Available-for-Sale	926.1	908.1
Debt Securities, Available-for-Sale, Unrealized Gain	6.3	3.6
Debt Securities, Available-for-Sale, Unrealized Loss	23.1	26.9
System Energy [Member]
Debt Securities, Available-for-Sale [Line Items]
Debt Securities, Available-for-Sale	574.9	559.8
Debt Securities, Available-for-Sale, Unrealized Gain	4.7	1.9
Debt Securities, Available-for-Sale, Unrealized Loss	$ 20.6	$ 27.6