Common Equity (Narrative) (Details) $ / shares in Units, $ in Thousands	1 Months Ended	12 Months Ended
	Oct. 31, 2010 USD ($)	Dec. 31, 2017 USD ($) plan $ / shares	Dec. 31, 2016 USD ($) $ / shares	Dec. 31, 2015 USD ($) $ / shares
Number of equity ownership plans | plan		3
Authorization of repurchase of common stock	$ 500,000	$ 350,000
Common Stock, Dividends, Per Share, Declared | $ / shares		$ 3.50	$ 3.42	$ 3.34
Dividend payments received from subsidiaries		$ 201,000	$ 165,000	$ 615,000
Dividends, Common Stock, Cash		628,885	611,835	598,897
Entergy Arkansas [Member]
Dividends, Common Stock, Cash		$ 15,000
Ratio of Common Stock Equity to Total Capitalization Which Could Result In Restriction of Dividends		25.00%
Entergy Mississippi [Member]
Dividends, Common Stock, Cash		$ 26,000	24,000	40,000
Ratio of Common Stock Equity to Total Capitalization Which Could Result In Restriction of Dividends		25.00%
System Energy [Member]
Dividends, Common Stock, Cash		$ 106,610	139,000	200,750
Common Stock [Member]
Dividends, Common Stock, Cash		0	0	0
Common Stock [Member] | Entergy Arkansas [Member]
Dividends, Common Stock, Cash		0
Common Stock [Member] | Entergy Mississippi [Member]
Dividends, Common Stock, Cash		0	0	0
Common Stock [Member] | System Energy [Member]
Dividends, Common Stock, Cash		$ 21,000	$ 40,000	$ 70,000