Revenue Recognition (Allowance for Doubtful Accounts) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Allowance for Doubtful Other Receivables, Current	$ 117.7	$ 7.4
Accounts Receivable, Allowance for Credit Loss, Period Increase (Decrease)	109.0
Accounts Receivable, Allowance for Credit Loss, Writeoff	(8.6)
Accounts Receivable, Allowance for Credit Loss, Recovery	9.9
Regulatory asset related to incremental bad debt expense resulting from COVID-19	87.1
Entergy Arkansas [Member]
Allowance for Doubtful Other Receivables, Current	18.3	1.2
Accounts Receivable, Allowance for Credit Loss, Period Increase (Decrease)	16.2
Accounts Receivable, Allowance for Credit Loss, Writeoff	(1.8)
Accounts Receivable, Allowance for Credit Loss, Recovery	2.7
Regulatory asset related to costs associated with COVID-19 pandemic	10.5
Regulatory asset related to incremental bad debt expense resulting from COVID-19	10.5
Entergy Louisiana [Member]
Allowance for Doubtful Other Receivables, Current	45.7	1.9
Accounts Receivable, Allowance for Credit Loss, Period Increase (Decrease)	43.7
Accounts Receivable, Allowance for Credit Loss, Writeoff	(3.5)
Accounts Receivable, Allowance for Credit Loss, Recovery	3.6
Regulatory asset related to costs associated with COVID-19 pandemic	48.8
Regulatory asset related to incremental bad debt expense resulting from COVID-19	36.0
Entergy New Orleans [Member]
Allowance for Doubtful Other Receivables, Current	17.4	3.2
Accounts Receivable, Allowance for Credit Loss, Period Increase (Decrease)	14.1
Accounts Receivable, Allowance for Credit Loss, Writeoff	(1.0)
Accounts Receivable, Allowance for Credit Loss, Recovery	1.1
Regulatory asset related to costs associated with COVID-19 pandemic	14.3
Regulatory asset related to incremental bad debt expense resulting from COVID-19	12.2
Entergy Mississippi [Member]
Allowance for Doubtful Other Receivables, Current	19.5	0.6
Accounts Receivable, Allowance for Credit Loss, Period Increase (Decrease)	18.8
Accounts Receivable, Allowance for Credit Loss, Writeoff	(1.2)
Accounts Receivable, Allowance for Credit Loss, Recovery	1.3
Regulatory asset related to costs associated with COVID-19 pandemic	19.2
Regulatory asset related to incremental bad debt expense resulting from COVID-19	15.5
Entergy Texas [Member]
Allowance for Doubtful Other Receivables, Current	16.8	$ 0.5
Accounts Receivable, Allowance for Credit Loss, Period Increase (Decrease)	16.2
Accounts Receivable, Allowance for Credit Loss, Writeoff	(1.1)
Accounts Receivable, Allowance for Credit Loss, Recovery	1.2
Regulatory asset related to costs associated with COVID-19 pandemic	12.9
Regulatory asset related to incremental bad debt expense resulting from COVID-19	$ 12.9