Leases (Narrative) (Details) - USD ($)	1 Months Ended	12 Months Ended
	Mar. 31, 2016	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2019	Jan. 31, 2019	Dec. 31, 2015	Dec. 31, 1989	Dec. 31, 1988
Operating Lease, Right-of-Use Asset					$ 234,000,000
Finance Lease, Right-of-Use Asset					61,000,000
Operating and Finance Lease Right of Use Asset and Lease Liabilities at Implementation						$ 263,000,000
Rent expense		$ 47,800,000	$ 53,100,000	$ 44,400,000
Entergy Arkansas [Member]
Operating Lease, Right-of-Use Asset					52,317,000
Finance Lease, Right-of-Use Asset					11,216,000
Operating and Finance Lease Right of Use Asset and Lease Liabilities at Implementation						59,000,000
Rent expense		6,200,000	7,500,000	8,000,000.0
Payments For Railcar Operating Lease		2,800,000	4,000,000	3,400,000
Regulatory Assets		138,300,000			168,900,000
Entergy Louisiana [Member]
Operating Lease, Right-of-Use Asset					36,034,000
Finance Lease, Right-of-Use Asset					17,209,000
Operating and Finance Lease Right of Use Asset and Lease Liabilities at Implementation						51,000,000
Portion of Waterford 3 purchase price satisfied through issuance of debt	$ 52,000,000
Rent expense		20,200,000	23,000,000.0	17,800,000
Payments For Railcar Operating Lease		400,000	300,000	300,000
Sale Leaseback Transaction, Net Book Value							$ 62,700,000
Net regulatory liability related to sale and leaseback transaction		$ 18,800,000			2,400,000
Liability related to undivided interests in Waterford 3							60,000,000	$ 353,600,000
Cash payment representing the purchase price to acquire the undivided interests in Waterford 3	$ 60,000,000
Reduction in liability related to undivided interest in Waterford 3							60,000,000
Reduced liability related to undivided interests in Waterford 3							$ 2,700,000
Percentage Of Capacity And Energy Purchased Under Purchased Power Agreement		50.00%
Entergy Mississippi [Member]
Operating Lease, Right-of-Use Asset					16,900,000
Finance Lease, Right-of-Use Asset					6,869,000
Operating and Finance Lease Right of Use Asset and Lease Liabilities at Implementation						26,000,000
Rent expense		$ 4,600,000	5,600,000	4,000,000.0
Regulatory Assets		63,500,000			80,800,000
Oil Tank Facilities Lease Payments		100,000	1,600,000	1,600,000
Entergy New Orleans [Member]
Operating Lease, Right-of-Use Asset					3,878,000
Finance Lease, Right-of-Use Asset					3,291,000
Operating and Finance Lease Right of Use Asset and Lease Liabilities at Implementation						7,000,000
Rent expense		2,500,000	2,500,000	900,000
Regulatory Assets		49,300,000			52,900,000
Entergy Texas [Member]
Operating Lease, Right-of-Use Asset					14,020,000
Finance Lease, Right-of-Use Asset					5,273,000
Operating and Finance Lease Right of Use Asset and Lease Liabilities at Implementation						$ 16,000,000
Rent expense		3,100,000	3,400,000	2,800,000
Regulatory Assets		50,900,000			42,500,000
Capacity expense under purchase power agreements accounted for as operating leases		$ 30,500,000	34,100,000	26,100,000
Percent of minimum payments		100.00%
System Energy [Member]
Rent expense		$ 1,900,000	2,200,000	1,600,000
Sale Leaseback Transaction, Net Book Value									$ 500,000,000
Regulatory Assets		76,400,000			75,900,000
Net regulatory liability related to sale and leaseback transaction		55,600,000
System Energy [Member] | Grand Gulf [Member]
Sale Leaseback Transaction, Net Book Value									$ 500,000,000
Regulatory Assets		0
Net regulatory liability related to sale and leaseback transaction		$ 55,600,000	$ 55,600,000		$ 55,600,000
Waterford 3 [Member]
Minimum Lease Payments, Sale Leaseback Transactions				57,500,000
Interest Portion of Minimum Lease Payments, Sale Leaseback Transactions				$ 2,300,000