DECOMMISSIONING TRUST FUNDS (Entergy Corporation, Entergy Arkansas, Entergy Louisiana, and System Energy) (Summary of Available-for-Sale Debt Securities Held) (Details) - USD ($) $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2026	Dec. 31, 2025
Debt Securities, Available-for-Sale [Line Items]
Fair value	$ 2,410.0	$ 2,202.0
Unrealized gains	462.0	28.0
Unrealized losses	167.0	45.0
ENTERGY ARKANSAS, LLC
Debt Securities, Available-for-Sale [Line Items]
Fair value	674.0	614.0
Unrealized gains	0.0	7.5
Unrealized losses	53.6	14.2
ENTERGY LOUISIANA, LLC
Debt Securities, Available-for-Sale [Line Items]
Fair value	1,082.6	992.6
Unrealized gains	0.2	13.0
Unrealized losses	65.1	15.0
SYSTEM ENERGY RESOURCES, INC.
Debt Securities, Available-for-Sale [Line Items]
Fair value	653.6	595.0
Unrealized gains	0.2	7.4
Unrealized losses	$ 48.5	$ 16.2