Decommissioning Trust Funds (Schedule of Available-for-Sale Securities Reconciliation) (Details) - USD ($) $ in Millions	6 Months Ended	12 Months Ended
	Jun. 30, 2025	Dec. 31, 2024
Debt Securities, Available-for-Sale [Line Items]
Debt Securities, Available-for-Sale	$ 2,107.0	$ 2,047.0
Debt Securities, Available-for-Sale, Unrealized Gain	20.0	7.0
Debt Securities, Available-for-Sale, Unrealized Loss	60.0	80.0
Entergy Arkansas [Member]
Debt Securities, Available-for-Sale [Line Items]
Debt Securities, Available-for-Sale	594.1	579.0
Debt Securities, Available-for-Sale, Unrealized Gain	5.4	1.2
Debt Securities, Available-for-Sale, Unrealized Loss	17.5	25.8
Entergy Louisiana [Member]
Debt Securities, Available-for-Sale [Line Items]
Debt Securities, Available-for-Sale	931.3	908.1
Debt Securities, Available-for-Sale, Unrealized Gain	8.1	3.6
Debt Securities, Available-for-Sale, Unrealized Loss	24.1	26.9
System Energy [Member]
Debt Securities, Available-for-Sale [Line Items]
Debt Securities, Available-for-Sale	582.1	559.8
Debt Securities, Available-for-Sale, Unrealized Gain	6.1	1.9
Debt Securities, Available-for-Sale, Unrealized Loss	$ 19.0	$ 27.6