Decommissioning Trust Funds (Schedule of Realized Gain (Loss)) (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2026	Mar. 31, 2025
Proceeds from Sale of Debt Securities, Available-for-sale	$ 159.0	$ 262.0
Debt Securities, Available-for-Sale, Realized Gain	1.0	1.0
Debt Securities, Available-for-Sale, Realized Loss	2.0	4.0
System Energy [Member]
Proceeds from Sale of Debt Securities, Available-for-sale	79.0	152.3
Debt Securities, Available-for-Sale, Realized Gain	0.3	0.6
Debt Securities, Available-for-Sale, Realized Loss	0.7	2.7
Entergy Louisiana [Member]
Proceeds from Sale of Debt Securities, Available-for-sale	75.7	110.0
Debt Securities, Available-for-Sale, Realized Gain	0.4	0.1
Debt Securities, Available-for-Sale, Realized Loss	1.5	1.5
Entergy Arkansas [Member]
Proceeds from Sale of Debt Securities, Available-for-sale	3.8	0.0
Debt Securities, Available-for-Sale, Realized Gain	0.0	0.0
Debt Securities, Available-for-Sale, Realized Loss	$ 0.1	$ 0.0

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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