Business Segment Information Business Segment Information (Restructuring Costs) (Details) - Entergy Wholesale Commodities [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Restructuring Cost and Reserve [Line Items]
Restructuring costs	$ 113.0	$ 95.0
Paid in cash	100.0	1.0
Non-cash portion	(7.0)	(3.0)
Restructuring Reserve	97.0	91.0	$ 0.0
Employee Retention and Severances Expenses and Other Benefits-Related Costs [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring costs	113.0	74.0
Paid in cash	100.0	1.0
Non-cash portion	0.0	(3.0)
Restructuring Reserve	83.0	70.0	0.0
Economic Development Costs [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring costs	0.0	21.0
Paid in cash	0.0	0.0
Non-cash portion	(7.0)	0.0
Restructuring Reserve	$ 14.0	$ 21.0	$ 0.0