Leases (Narrative) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Jan. 31, 2019	Dec. 31, 1988
Operating Lease, Right-of-Use Asset	$ 230,000,000	$ 234,000,000
Finance Lease, Right-of-Use Asset	60,000,000	61,000,000
Operating and Finance Lease Right of Use Asset and Lease Liabilities at Implementation				$ 263,000,000
Rent expense			$ 47,800,000
Operating Lease, Expense	67,471,000	63,566,000
Finance Lease, Right-of-Use Asset, Amortization	12,180,000	16,048,000
Finance Lease, Interest Expense	2,884,000	3,667,000
Short-term Lease, Cost	759,000	43,000
Entergy Arkansas [Member]
Operating Lease, Right-of-Use Asset	55,840,000	52,317,000
Finance Lease, Right-of-Use Asset	12,447,000	11,216,000
Operating and Finance Lease Right of Use Asset and Lease Liabilities at Implementation				59,000,000
Rent expense			6,200,000
Payments For Railcar Operating Lease			2,800,000
Regulatory Assets	212,600,000	168,900,000
Operating Lease, Expense	14,344,000	13,213,000
Finance Lease, Right-of-Use Asset, Amortization	2,693,000	3,643,000
Finance Lease, Interest Expense	408,000	594,000
Short-term Lease, Cost	43,000
Entergy Louisiana [Member]
Operating Lease, Right-of-Use Asset	43,189,000	36,034,000
Finance Lease, Right-of-Use Asset	16,425,000	17,209,000
Operating and Finance Lease Right of Use Asset and Lease Liabilities at Implementation				51,000,000
Rent expense			20,200,000
Payments For Railcar Operating Lease			400,000
Regulatory Assets	302,500,000
Net regulatory liability related to sale and leaseback transaction		2,400,000
Operating Lease, Expense	13,944,000	11,975,000
Finance Lease, Right-of-Use Asset, Amortization	4,097,000	5,940,000
Finance Lease, Interest Expense	597,000	895,000
Short-term Lease, Cost	719,000	43,000
Entergy Mississippi [Member]
Operating Lease, Right-of-Use Asset	16,538,000	16,900,000
Finance Lease, Right-of-Use Asset	7,452,000	6,869,000
Operating and Finance Lease Right of Use Asset and Lease Liabilities at Implementation				26,000,000
Rent expense			4,600,000
Regulatory Assets	107,300,000	80,800,000
Oil Tank Facilities Lease Payments			100,000
Operating Lease, Expense	6,584,000	6,927,000
Finance Lease, Right-of-Use Asset, Amortization	1,627,000	2,097,000
Finance Lease, Interest Expense	254,000	353,000
Entergy New Orleans [Member]
Operating Lease, Right-of-Use Asset	5,222,000	3,878,000
Finance Lease, Right-of-Use Asset	3,428,000	3,291,000
Operating and Finance Lease Right of Use Asset and Lease Liabilities at Implementation				7,000,000
Rent expense			2,500,000
Regulatory Assets	63,200,000	52,900,000
Operating Lease, Expense	1,443,000	1,406,000
Finance Lease, Right-of-Use Asset, Amortization	712,000	1,042,000
Finance Lease, Interest Expense	120,000	168,000
Entergy Texas [Member]
Operating Lease, Right-of-Use Asset	14,738,000	14,020,000
Finance Lease, Right-of-Use Asset	5,719,000	5,273,000
Operating and Finance Lease Right of Use Asset and Lease Liabilities at Implementation				$ 16,000,000
Rent expense			3,100,000
Regulatory Assets	115,300,000	42,500,000
Capacity expense under purchase power agreements accounted for as operating leases			30,500,000
Operating Lease, Expense	4,870,000	4,259,000
Finance Lease, Right-of-Use Asset, Amortization	1,340,000	1,568,000
Finance Lease, Interest Expense	196,000	241,000
System Energy [Member]
Rent expense			$ 1,900,000
Regulatory Assets	92,900,000	75,900,000
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