Variable Interest Entities (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
System Energy [Member] | Grand Gulf [Member]
Variable Interest Entities (Textual) [Abstract]
Payments on lease, including interest	$ 17.2	$ 17.2	$ 17.2