Decommissioning Trust Funds (Schedule of Realized Gain (Loss)) (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2025	Mar. 31, 2024
Proceeds from Sale of Debt Securities, Available-for-sale	$ 262.0	$ 169.0
Debt Securities, Available-for-Sale, Realized Gain	1.0	0.0
Debt Securities, Available-for-Sale, Realized Loss	4.0	7.0
System Energy [Member]
Proceeds from Sale of Debt Securities, Available-for-sale	152.3	108.0
Debt Securities, Available-for-Sale, Realized Gain	0.6	0.2
Debt Securities, Available-for-Sale, Realized Loss	2.7	3.5
Entergy Louisiana [Member]
Proceeds from Sale of Debt Securities, Available-for-sale	110.0	48.4
Debt Securities, Available-for-Sale, Realized Gain	0.1	0.2
Debt Securities, Available-for-Sale, Realized Loss	1.5	2.9
Entergy Arkansas [Member]
Proceeds from Sale of Debt Securities, Available-for-sale	0.0	12.4
Debt Securities, Available-for-Sale, Realized Gain	0.0	0.0
Debt Securities, Available-for-Sale, Realized Loss	$ 0.0	$ 0.4

Amount of realized gain on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 9
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481800/320-10-50-9

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Amount of cash inflow from sale of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 11
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481830/320-10-45-11

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 9
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481800/320-10-50-9

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 12
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482740/230-10-45-12

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 230
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 11
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482740/230-10-45-11

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