Decommissioning Trust Funds (Schedule of Available-for-Sale Securities Reconciliation) (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Debt Securities, Available-for-Sale [Line Items]
Debt Securities, Available-for-Sale	$ 1,761.0	$ 1,770.0
Debt Securities [Member]
Debt Securities, Available-for-Sale [Line Items]
Debt Securities, Available-for-Sale, Unrealized Loss Position	142.0	134.0
Debt Securities, Available-for-Sale, Accumulated Gross Unrealized Gain, before Tax	10.0	19.0
Debt Securities, Available-for-Sale	1,761.0	1,770.0
Entergy Arkansas [Member]
Debt Securities, Available-for-Sale [Line Items]
Debt Securities, Available-for-Sale	498.8	496.9
Entergy Arkansas [Member] | Debt Securities [Member]
Debt Securities, Available-for-Sale [Line Items]
Debt Securities, Available-for-Sale, Unrealized Loss Position	57.5	53.6
Debt Securities, Available-for-Sale, Accumulated Gross Unrealized Gain, before Tax	1.4	2.4
Debt Securities, Available-for-Sale	498.8	496.9
Entergy Louisiana [Member]
Debt Securities, Available-for-Sale [Line Items]
Debt Securities, Available-for-Sale	780.4	788.1
Entergy Louisiana [Member] | Debt Securities [Member]
Debt Securities, Available-for-Sale [Line Items]
Debt Securities, Available-for-Sale, Unrealized Loss Position	40.3	37.4
Debt Securities, Available-for-Sale, Accumulated Gross Unrealized Gain, before Tax	5.9	11.7
Debt Securities, Available-for-Sale	780.4	788.1
System Energy [Member]
Debt Securities, Available-for-Sale [Line Items]
Debt Securities, Available-for-Sale	481.5	485.2
System Energy [Member] | Debt Securities [Member]
Debt Securities, Available-for-Sale [Line Items]
Debt Securities, Available-for-Sale, Unrealized Loss Position	44.6	42.5
Debt Securities, Available-for-Sale, Accumulated Gross Unrealized Gain, before Tax	2.7	4.5
Debt Securities, Available-for-Sale	$ 481.5	$ 485.2