Income Taxes Income Taxes (Narrative) (Details) - USD ($) $ in Millions	1 Months Ended	3 Months Ended	9 Months Ended
	Jun. 30, 2018	Sep. 30, 2018	Sep. 30, 2018	Dec. 31, 2017
Entergy Arkansas [Member]
Reduction to regulatory liability for income taxes resulting from return of unprotected excess ADIT		$ 153	$ 260
Entergy Louisiana [Member]
Tax benefits related to Hurricane Katrina and Hurricane Rita contingent sharing obligation	$ 52
Unrecognized Tax Benefits		855	855	$ 926
Reduction to regulatory liability for income taxes resulting from return of unprotected excess ADIT		55	86
Entergy Mississippi [Member]
Reduction to regulatory liability for income taxes resulting from return of unprotected excess ADIT		32	161
Entergy New Orleans [Member]
Reduction to regulatory liability for income taxes resulting from return of unprotected excess ADIT		9	9
System Energy [Member]
Reduction to regulatory liability for income taxes resulting from return of unprotected excess ADIT		34	46
Entergy Texas [Member]
Regulatory liability for protected excess ADIT		269	269
Regulatory liability for unprotected excess ADIT		201	$ 201
Entergy Wholesale Commodities [Member]
Reduction of Income Tax Expense, Net of Unrecognized Tax Benefits, Resulting From Tax Election		107
Tax Adjustments, Settlements, and Unusual Provisions		$ 23