Risk Management and Fair Values Assets And Liabilities At Fair Value On A Recurring Basis (Details) - USD ($)	Dec. 31, 2020	Dec. 31, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash Equivalents, at Carrying Value	$ 1,630,248,000	$ 391,480,000
Equity Securities, FV-NI	1,533,000,000	905,000,000
Assets at fair value on a recurring basis
Replacement Reserve Escrow	148,000,000	459,000,000
Restricted Cash and Cash Equivalents, Current	42,000,000	47,000,000
Liabilities at fair value on a recurring basis
Debt Securities	2,617,000,000	2,963,000,000
Assets, Fair Value Disclosure	9,122,000,000	7,430,000,000
Gas Hedge Contracts [Member]
Liabilities at fair value on a recurring basis
Derivative Liability	7,000,000	7,000,000
Common trust funds valued using Net Asset Value [Domain]
Liabilities at fair value on a recurring basis
Available-for-sale Securities	3,103,000,000	2,536,000,000
Power Contracts Assets [Member]
Liabilities at fair value on a recurring basis
Derivative Asset	38,000,000	118,000,000
Financial Transmission Rights (FTRs) [Member]
Liabilities at fair value on a recurring basis
Derivative Asset	9,000,000	10,000,000
Gas Hedge Contracts Assets [Member]
Liabilities at fair value on a recurring basis
Derivative Asset	2,000,000	1,000,000
Fair Value Inputs Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash Equivalents, at Carrying Value	1,630,000,000	391,000,000
Equity Securities, FV-NI	1,533,000,000	905,000,000
Assets at fair value on a recurring basis
Replacement Reserve Escrow	148,000,000	459,000,000
Restricted Cash and Cash Equivalents, Current	42,000,000	47,000,000
Liabilities at fair value on a recurring basis
Debt Securities	919,000,000	1,139,000,000
Assets, Fair Value Disclosure	4,273,000,000	2,941,000,000
Fair Value Inputs Level 1 [Member] | Gas Hedge Contracts [Member]
Liabilities at fair value on a recurring basis
Derivative Liability	6,000,000	5,000,000
Fair Value Inputs Level 1 [Member] | Power Contracts Assets [Member]
Liabilities at fair value on a recurring basis
Derivative Asset	0	0
Fair Value Inputs Level 1 [Member] | Financial Transmission Rights (FTRs) [Member]
Liabilities at fair value on a recurring basis
Derivative Asset	0	0
Fair Value Inputs Level 1 [Member] | Gas Hedge Contracts Assets [Member]
Liabilities at fair value on a recurring basis
Derivative Asset	1,000,000	0
Fair Value Inputs Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash Equivalents, at Carrying Value	0	0
Equity Securities, FV-NI	0	0
Assets at fair value on a recurring basis
Replacement Reserve Escrow	0	0
Restricted Cash and Cash Equivalents, Current	0	0
Liabilities at fair value on a recurring basis
Debt Securities	1,698,000,000	1,824,000,000
Assets, Fair Value Disclosure	1,699,000,000	1,825,000,000
Fair Value Inputs Level 2 [Member] | Gas Hedge Contracts [Member]
Liabilities at fair value on a recurring basis
Derivative Liability	1,000,000	2,000,000
Fair Value Inputs Level 2 [Member] | Power Contracts Assets [Member]
Liabilities at fair value on a recurring basis
Derivative Asset	0	0
Fair Value Inputs Level 2 [Member] | Financial Transmission Rights (FTRs) [Member]
Liabilities at fair value on a recurring basis
Derivative Asset	0	0
Fair Value Inputs Level 2 [Member] | Gas Hedge Contracts Assets [Member]
Liabilities at fair value on a recurring basis
Derivative Asset	1,000,000	1,000,000
Fair Value Inputs Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash Equivalents, at Carrying Value	0	0
Equity Securities, FV-NI	0	0
Assets at fair value on a recurring basis
Replacement Reserve Escrow	0	0
Restricted Cash and Cash Equivalents, Current	0	0
Liabilities at fair value on a recurring basis
Debt Securities	0	0
Assets, Fair Value Disclosure	47,000,000	128,000,000
Fair Value Inputs Level 3 [Member] | Gas Hedge Contracts [Member]
Liabilities at fair value on a recurring basis
Derivative Liability	0	0
Fair Value Inputs Level 3 [Member] | Power Contracts Assets [Member]
Liabilities at fair value on a recurring basis
Derivative Asset	38,000,000	118,000,000
Fair Value Inputs Level 3 [Member] | Financial Transmission Rights (FTRs) [Member]
Liabilities at fair value on a recurring basis
Derivative Asset	9,000,000	10,000,000
Fair Value Inputs Level 3 [Member] | Gas Hedge Contracts Assets [Member]
Liabilities at fair value on a recurring basis
Derivative Asset	0	0
Entergy New Orleans [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash Equivalents, at Carrying Value	0	5,991,000
Assets at fair value on a recurring basis
Replacement Reserve Escrow	83,000,000.0	82,600,000
Restricted Cash and Cash Equivalents, Current	3,400,000	2,000,000.0
Liabilities at fair value on a recurring basis
Assets, Fair Value Disclosure	86,500,000	90,900,000
Entergy New Orleans [Member] | Gas Hedge Contracts [Member]
Liabilities at fair value on a recurring basis
Derivative Liability	300,000	200,000
Entergy New Orleans [Member] | Financial Transmission Rights (FTRs) [Member]
Liabilities at fair value on a recurring basis
Derivative Asset	100,000	300,000
Entergy New Orleans [Member] | Fair Value Inputs Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash Equivalents, at Carrying Value		6,000,000.0
Assets at fair value on a recurring basis
Replacement Reserve Escrow	83,000,000.0	82,600,000
Restricted Cash and Cash Equivalents, Current	3,400,000	2,000,000.0
Liabilities at fair value on a recurring basis
Assets, Fair Value Disclosure	86,400,000	90,600,000
Entergy New Orleans [Member] | Fair Value Inputs Level 1 [Member] | Gas Hedge Contracts [Member]
Liabilities at fair value on a recurring basis
Derivative Liability	300,000	200,000
Entergy New Orleans [Member] | Fair Value Inputs Level 1 [Member] | Financial Transmission Rights (FTRs) [Member]
Liabilities at fair value on a recurring basis
Derivative Asset	0	0
Entergy New Orleans [Member] | Fair Value Inputs Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash Equivalents, at Carrying Value		0
Assets at fair value on a recurring basis
Replacement Reserve Escrow	0	0
Restricted Cash and Cash Equivalents, Current	0	0
Liabilities at fair value on a recurring basis
Assets, Fair Value Disclosure	0	0
Entergy New Orleans [Member] | Fair Value Inputs Level 2 [Member] | Gas Hedge Contracts [Member]
Liabilities at fair value on a recurring basis
Derivative Liability	0	0
Entergy New Orleans [Member] | Fair Value Inputs Level 2 [Member] | Financial Transmission Rights (FTRs) [Member]
Liabilities at fair value on a recurring basis
Derivative Asset	0	0
Entergy New Orleans [Member] | Fair Value Inputs Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash Equivalents, at Carrying Value		0
Assets at fair value on a recurring basis
Replacement Reserve Escrow	0	0
Restricted Cash and Cash Equivalents, Current	0	0
Liabilities at fair value on a recurring basis
Assets, Fair Value Disclosure	100,000	300,000
Entergy New Orleans [Member] | Fair Value Inputs Level 3 [Member] | Gas Hedge Contracts [Member]
Liabilities at fair value on a recurring basis
Derivative Liability	0	0
Entergy New Orleans [Member] | Fair Value Inputs Level 3 [Member] | Financial Transmission Rights (FTRs) [Member]
Liabilities at fair value on a recurring basis
Derivative Asset	100,000	300,000
Entergy Mississippi [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash Equivalents, at Carrying Value	7,000	51,590,000
Assets at fair value on a recurring basis
Replacement Reserve Escrow	64,600,000	80,200,000
Liabilities at fair value on a recurring basis
Assets, Fair Value Disclosure	65,200,000	132,600,000
Entergy Mississippi [Member] | Gas Hedge Contracts [Member]
Liabilities at fair value on a recurring basis
Derivative Liability	5,000,000.0	2,300,000
Entergy Mississippi [Member] | Financial Transmission Rights (FTRs) [Member]
Liabilities at fair value on a recurring basis
Derivative Asset	600,000	800,000
Entergy Mississippi [Member] | Fair Value Inputs Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash Equivalents, at Carrying Value		51,600,000
Assets at fair value on a recurring basis
Replacement Reserve Escrow	64,600,000	80,200,000
Liabilities at fair value on a recurring basis
Assets, Fair Value Disclosure	64,600,000	131,800,000
Entergy Mississippi [Member] | Fair Value Inputs Level 1 [Member] | Gas Hedge Contracts [Member]
Liabilities at fair value on a recurring basis
Derivative Liability	5,000,000.0	2,300,000
Entergy Mississippi [Member] | Fair Value Inputs Level 1 [Member] | Financial Transmission Rights (FTRs) [Member]
Liabilities at fair value on a recurring basis
Derivative Asset	0	0
Entergy Mississippi [Member] | Fair Value Inputs Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash Equivalents, at Carrying Value		0
Assets at fair value on a recurring basis
Replacement Reserve Escrow	0	0
Liabilities at fair value on a recurring basis
Assets, Fair Value Disclosure	0	0
Entergy Mississippi [Member] | Fair Value Inputs Level 2 [Member] | Gas Hedge Contracts [Member]
Liabilities at fair value on a recurring basis
Derivative Liability	0	0
Entergy Mississippi [Member] | Fair Value Inputs Level 2 [Member] | Financial Transmission Rights (FTRs) [Member]
Liabilities at fair value on a recurring basis
Derivative Asset	0	0
Entergy Mississippi [Member] | Fair Value Inputs Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash Equivalents, at Carrying Value		0
Assets at fair value on a recurring basis
Replacement Reserve Escrow	0	0
Liabilities at fair value on a recurring basis
Assets, Fair Value Disclosure	600,000	800,000
Entergy Mississippi [Member] | Fair Value Inputs Level 3 [Member] | Gas Hedge Contracts [Member]
Liabilities at fair value on a recurring basis
Derivative Liability	0	0
Entergy Mississippi [Member] | Fair Value Inputs Level 3 [Member] | Financial Transmission Rights (FTRs) [Member]
Liabilities at fair value on a recurring basis
Derivative Asset	600,000	800,000
Entergy Louisiana [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash Equivalents, at Carrying Value	726,717,000	1,518,000
Equity Securities, FV-NI	8,700,000	4,300,000
Assets at fair value on a recurring basis
Replacement Reserve Escrow		295,900,000
Restricted Cash and Cash Equivalents, Current	2,700,000	3,700,000
Liabilities at fair value on a recurring basis
Debt Securities	632,200,000	601,500,000
Assets, Fair Value Disclosure	2,528,900,000	1,870,200,000
Entergy Louisiana [Member] | Gas Hedge Contracts [Member]
Liabilities at fair value on a recurring basis
Derivative Liability	1,600,000	4,600,000
Entergy Louisiana [Member] | Common trust funds valued using Net Asset Value [Domain]
Liabilities at fair value on a recurring basis
Available-for-sale Securities	1,153,100,000	958,000,000.0
Entergy Louisiana [Member] | Financial Transmission Rights (FTRs) [Member]
Liabilities at fair value on a recurring basis
Derivative Asset	4,200,000	4,500,000
Entergy Louisiana [Member] | Gas Hedge Contracts Assets [Member]
Liabilities at fair value on a recurring basis
Derivative Asset	1,300,000	800,000
Entergy Louisiana [Member] | Fair Value Inputs Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash Equivalents, at Carrying Value	726,700,000	1,500,000
Equity Securities, FV-NI	8,700,000	4,300,000
Assets at fair value on a recurring basis
Replacement Reserve Escrow		295,900,000
Restricted Cash and Cash Equivalents, Current	2,700,000	3,700,000
Liabilities at fair value on a recurring basis
Debt Securities	172,400,000	180,800,000
Assets, Fair Value Disclosure	911,300,000	486,200,000
Entergy Louisiana [Member] | Fair Value Inputs Level 1 [Member] | Gas Hedge Contracts [Member]
Liabilities at fair value on a recurring basis
Derivative Liability	300,000	2,400,000
Entergy Louisiana [Member] | Fair Value Inputs Level 1 [Member] | Financial Transmission Rights (FTRs) [Member]
Liabilities at fair value on a recurring basis
Derivative Asset	0	0
Entergy Louisiana [Member] | Fair Value Inputs Level 1 [Member] | Gas Hedge Contracts Assets [Member]
Liabilities at fair value on a recurring basis
Derivative Asset	800,000	0
Entergy Louisiana [Member] | Fair Value Inputs Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash Equivalents, at Carrying Value	0	0
Equity Securities, FV-NI	0	0
Assets at fair value on a recurring basis
Replacement Reserve Escrow		0
Restricted Cash and Cash Equivalents, Current	0	0
Liabilities at fair value on a recurring basis
Debt Securities	459,800,000	420,700,000
Assets, Fair Value Disclosure	460,300,000	421,500,000
Entergy Louisiana [Member] | Fair Value Inputs Level 2 [Member] | Gas Hedge Contracts [Member]
Liabilities at fair value on a recurring basis
Derivative Liability	1,300,000	2,200,000
Entergy Louisiana [Member] | Fair Value Inputs Level 2 [Member] | Financial Transmission Rights (FTRs) [Member]
Liabilities at fair value on a recurring basis
Derivative Asset	0	0
Entergy Louisiana [Member] | Fair Value Inputs Level 2 [Member] | Gas Hedge Contracts Assets [Member]
Liabilities at fair value on a recurring basis
Derivative Asset	500,000	800,000
Entergy Louisiana [Member] | Fair Value Inputs Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash Equivalents, at Carrying Value	0	0
Equity Securities, FV-NI	0	0
Assets at fair value on a recurring basis
Replacement Reserve Escrow		0
Restricted Cash and Cash Equivalents, Current	0	0
Liabilities at fair value on a recurring basis
Debt Securities	0	0
Assets, Fair Value Disclosure	4,200,000	4,500,000
Entergy Louisiana [Member] | Fair Value Inputs Level 3 [Member] | Gas Hedge Contracts [Member]
Liabilities at fair value on a recurring basis
Derivative Liability	0	0
Entergy Louisiana [Member] | Fair Value Inputs Level 3 [Member] | Financial Transmission Rights (FTRs) [Member]
Liabilities at fair value on a recurring basis
Derivative Asset	4,200,000	4,500,000
Entergy Louisiana [Member] | Fair Value Inputs Level 3 [Member] | Gas Hedge Contracts Assets [Member]
Liabilities at fair value on a recurring basis
Derivative Asset	0	0
Entergy Texas [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Temporary Cash Investments Fair Value	248,600,000	12,900,000
Cash Equivalents, at Carrying Value	248,570,000	12,904,000
Liabilities at fair value on a recurring basis
Assets, Fair Value Disclosure	286,400,000	51,500,000
Entergy Texas [Member] | Securitization Recovery Trust Account [Member]
Assets at fair value on a recurring basis
Restricted Cash and Cash Equivalents, Current	36,200,000	37,700,000
Entergy Texas [Member] | Financial Transmission Rights (FTRs) [Member]
Liabilities at fair value on a recurring basis
Derivative Asset	1,600,000	900,000
Entergy Texas [Member] | Fair Value Inputs Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Temporary Cash Investments Fair Value	248,600,000	12,900,000
Liabilities at fair value on a recurring basis
Assets, Fair Value Disclosure	284,800,000	50,600,000
Entergy Texas [Member] | Fair Value Inputs Level 1 [Member] | Securitization Recovery Trust Account [Member]
Assets at fair value on a recurring basis
Restricted Cash and Cash Equivalents, Current	36,200,000	37,700,000
Entergy Texas [Member] | Fair Value Inputs Level 1 [Member] | Financial Transmission Rights (FTRs) [Member]
Liabilities at fair value on a recurring basis
Derivative Asset	0	0
Entergy Texas [Member] | Fair Value Inputs Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Temporary Cash Investments Fair Value	0	0
Liabilities at fair value on a recurring basis
Assets, Fair Value Disclosure	0	0
Entergy Texas [Member] | Fair Value Inputs Level 2 [Member] | Securitization Recovery Trust Account [Member]
Assets at fair value on a recurring basis
Restricted Cash and Cash Equivalents, Current	0	0
Entergy Texas [Member] | Fair Value Inputs Level 2 [Member] | Financial Transmission Rights (FTRs) [Member]
Liabilities at fair value on a recurring basis
Derivative Asset	0	0
Entergy Texas [Member] | Fair Value Inputs Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Temporary Cash Investments Fair Value	0	0
Liabilities at fair value on a recurring basis
Assets, Fair Value Disclosure	1,600,000	900,000
Entergy Texas [Member] | Fair Value Inputs Level 3 [Member] | Securitization Recovery Trust Account [Member]
Assets at fair value on a recurring basis
Restricted Cash and Cash Equivalents, Current	0	0
Entergy Texas [Member] | Fair Value Inputs Level 3 [Member] | Financial Transmission Rights (FTRs) [Member]
Liabilities at fair value on a recurring basis
Derivative Asset	1,600,000	900,000
Entergy Arkansas [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash Equivalents, at Carrying Value	168,020,000	0
Equity Securities, FV-NI	1,300,000	600,000
Assets at fair value on a recurring basis
Restricted Cash and Cash Equivalents, Current		4,000,000.0
Liabilities at fair value on a recurring basis
Debt Securities	447,900,000	412,800,000
Assets, Fair Value Disclosure	1,444,600,000	1,108,600,000
Entergy Arkansas [Member] | Common trust funds valued using Net Asset Value [Domain]
Liabilities at fair value on a recurring basis
Available-for-sale Securities	824,700,000	687,900,000
Entergy Arkansas [Member] | Financial Transmission Rights (FTRs) [Member]
Liabilities at fair value on a recurring basis
Derivative Asset	2,700,000	3,300,000
Entergy Arkansas [Member] | Fair Value Inputs Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash Equivalents, at Carrying Value	168,000,000.0
Equity Securities, FV-NI	1,300,000	600,000
Assets at fair value on a recurring basis
Restricted Cash and Cash Equivalents, Current		4,000,000.0
Liabilities at fair value on a recurring basis
Debt Securities	98,200,000	108,700,000
Assets, Fair Value Disclosure	267,500,000	113,300,000
Entergy Arkansas [Member] | Fair Value Inputs Level 1 [Member] | Financial Transmission Rights (FTRs) [Member]
Liabilities at fair value on a recurring basis
Derivative Asset	0	0
Entergy Arkansas [Member] | Fair Value Inputs Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash Equivalents, at Carrying Value	0
Equity Securities, FV-NI	0	0
Assets at fair value on a recurring basis
Restricted Cash and Cash Equivalents, Current		0
Liabilities at fair value on a recurring basis
Debt Securities	349,700,000	304,100,000
Assets, Fair Value Disclosure	349,700,000	304,100,000
Entergy Arkansas [Member] | Fair Value Inputs Level 2 [Member] | Financial Transmission Rights (FTRs) [Member]
Liabilities at fair value on a recurring basis
Derivative Asset	0	0
Entergy Arkansas [Member] | Fair Value Inputs Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash Equivalents, at Carrying Value	0
Equity Securities, FV-NI	0	0
Assets at fair value on a recurring basis
Restricted Cash and Cash Equivalents, Current		0
Liabilities at fair value on a recurring basis
Debt Securities	0	0
Assets, Fair Value Disclosure	2,700,000	3,300,000
Entergy Arkansas [Member] | Fair Value Inputs Level 3 [Member] | Financial Transmission Rights (FTRs) [Member]
Liabilities at fair value on a recurring basis
Derivative Asset	2,700,000	3,300,000
System Energy [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash Equivalents, at Carrying Value	216,383,000	68,441,000
Equity Securities, FV-NI	3,800,000	13,300,000
Liabilities at fair value on a recurring basis
Debt Securities	427,700,000	386,200,000
Assets, Fair Value Disclosure	1,432,300,000	1,122,500,000
System Energy [Member] | Common trust funds valued using Net Asset Value [Domain]
Liabilities at fair value on a recurring basis
Available-for-sale Securities	784,400,000	654,600,000
System Energy [Member] | Fair Value Inputs Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash Equivalents, at Carrying Value	216,400,000	68,400,000
Equity Securities, FV-NI	3,800,000	13,300,000
Liabilities at fair value on a recurring basis
Debt Securities	177,300,000	176,300,000
Assets, Fair Value Disclosure	397,500,000	258,000,000.0
System Energy [Member] | Fair Value Inputs Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash Equivalents, at Carrying Value	0	0
Equity Securities, FV-NI	0	0
Liabilities at fair value on a recurring basis
Debt Securities	250,400,000	209,900,000
Assets, Fair Value Disclosure	250,400,000	209,900,000
System Energy [Member] | Fair Value Inputs Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash Equivalents, at Carrying Value	0	0
Equity Securities, FV-NI	0	0
Liabilities at fair value on a recurring basis
Debt Securities	0	0
Assets, Fair Value Disclosure	$ 0	$ 0