Income Taxes Income Taxes (Summary of Interest on Income Taxes Expense Related to Unrecognized Tax Benefits) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Unrecognized Tax Expense, Income Tax Penalties and Interest Expense		$ (4.0)
Entergy Arkansas [Member]
Unrecognized Tax Benefits, Income Tax Penalties and Interest Expense	$ 0.4		$ 1.4
Unrecognized Tax Expense, Income Tax Penalties and Interest Expense		(0.8)
Entergy Louisiana [Member]
Unrecognized Tax Benefits, Income Tax Penalties and Interest Expense	0.3
Unrecognized Tax Expense, Income Tax Penalties and Interest Expense		(10.8)	(3.7)
Entergy Mississippi [Member]
Unrecognized Tax Benefits, Income Tax Penalties and Interest Expense	0.5	0.2	0.5
Entergy New Orleans [Member]
Unrecognized Tax Benefits, Income Tax Penalties and Interest Expense	1.3		2.0
Unrecognized Tax Expense, Income Tax Penalties and Interest Expense		(0.8)
Entergy Texas [Member]
Unrecognized Tax Benefits, Income Tax Penalties and Interest Expense	0.2		0.2
Unrecognized Tax Expense, Income Tax Penalties and Interest Expense		(0.2)
System Energy [Member]
Unrecognized Tax Benefits, Income Tax Penalties and Interest Expense	$ 0.2		$ 1.3
Unrecognized Tax Expense, Income Tax Penalties and Interest Expense		$ (2.6)