Decommissioning Trust Funds (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017	Jan. 01, 2018
Debt Securities, Trading, Measurement Input	$ 397,000		$ 397,000
Decommissioning Trust Funds [Abstract]
Accumulated Other Comprehensive Income (Loss), Financial Liability, Fair Value Option, after Tax						$ (632,617)
Deferred taxes on unrealized gains/(losses) recorded in OCI for non-regulated decommissioning trusts	(825)	$ 30,644	1,708	$ 72,808
Amortized cost of debt securities	$ 2,489,000		$ 2,489,000		$ 2,539,000
Average coupon rate of debt securities	3.36%		3.36%
Average duration of debt securities, years			5 years 358 days
Average maturity of debt securities, years			10 years 146 days
Proceeds from the dispositions of debt securities	$ 2,377,000	440,000	$ 4,178,000	1,903,000
Gains from dispositions of debt securities, gross	4,000	9,000	6,000	79,000
Losses from dispositions of debt securities, gross	15,000	2,000	37,000	9,000
Equity Securities, FV-NI, Unrealized Gain	369,000		464,000
Equity Securities [Member]
Decommissioning Trust Funds [Abstract]
Deferred taxes on unrealized gains/(losses) recorded in OCI for non-regulated decommissioning trusts					472,000
Debt Securities [Member]
Decommissioning Trust Funds [Abstract]
Deferred taxes on unrealized gains/(losses) recorded in OCI for non-regulated decommissioning trusts			(6,000)		7,000
Entergy Arkansas [Member]
Decommissioning Trust Funds [Abstract]
Amortized cost of debt securities	$ 389,200		$ 389,200		349,100
Average coupon rate of debt securities	2.68%		2.68%
Average duration of debt securities, years			4 years 219 days
Average maturity of debt securities, years			6 years 172 days
Proceeds from the dispositions of debt securities	$ 137,900	51,900	$ 259,300	219,200
Gains from dispositions of debt securities, gross	10	0	100	11,700
Losses from dispositions of debt securities, gross	600	0	3,000	200
Equity Securities, FV-NI, Unrealized Gain	37,800		46,000
Entergy Louisiana [Member]
Decommissioning Trust Funds [Abstract]
Amortized cost of debt securities	$ 527,800		$ 527,800		490,000
Average coupon rate of debt securities	4.07%		4.07%
Average duration of debt securities, years			6 years 271 days
Average maturity of debt securities, years			13 years 274 days
Proceeds from the dispositions of debt securities	$ 773,900	50,500	$ 943,300	176,100
Gains from dispositions of debt securities, gross	1,900	2,900	2,500	7,900
Losses from dispositions of debt securities, gross	3,600	100	$ 4,800	400
Percentage Interest in River Bend			30.00%
Equity Securities, FV-NI, Unrealized Gain	55,000		$ 66,300
System Energy [Member]
Decommissioning Trust Funds [Abstract]
Amortized cost of debt securities	$ 365,500		$ 365,500		327,500
Average coupon rate of debt securities	2.95%		2.95%
Average duration of debt securities, years			6 years 73 days
Average maturity of debt securities, years			9 years 29 days
Proceeds from the dispositions of debt securities	$ 157,800	54,600	$ 357,200	308,100
Gains from dispositions of debt securities, gross	0	200	300	700
Losses from dispositions of debt securities, gross	300	$ 200	4,800	$ 1,500
Equity Securities, FV-NI, Unrealized Gain	35,900		43,800
Indian Point 3 [Member]
Decommissioning Trust Funds [Abstract]
Decommissioning Fund Investments, Fair Value	835,000		835,000		798,000
Indian Point 1 [Member]
Decommissioning Trust Funds [Abstract]
Decommissioning Fund Investments, Fair Value	509,000		509,000		491,000
Indian Point 2 [Member]
Decommissioning Trust Funds [Abstract]
Decommissioning Fund Investments, Fair Value	644,000		644,000		621,000
Palisades [Member]
Decommissioning Trust Funds [Abstract]
Decommissioning Fund Investments, Fair Value	476,000		476,000		458,000
Pilgrim [Member]
Decommissioning Trust Funds [Abstract]
Decommissioning Fund Investments, Fair Value	1,081,000		1,081,000		1,068,000
Vermont Yankee [Member]
Decommissioning Trust Funds [Abstract]
Decommissioning Fund Investments, Fair Value	$ 554,000		$ 554,000		$ 613,000