Commitments and Contingencies Commitments And Contingencies (Narrative) (Details) (Details) $ in Millions	1 Months Ended	9 Months Ended	12 Months Ended
	Aug. 31, 2014 USD ($)	Sep. 30, 2015 USD ($) MW	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Regulatory Assets [Line Items]
Damages claim filed in demand for arbitration	$ 165.0
Number of contracts under which nuclear fuel enrichment services are purchased		2
Entergy Mississippi [Member]
Regulatory Assets [Line Items]
Proceeds From Insurance Settlement, Operating and Investing Activities		$ 28.2
Capital expense related to Baxter Wilson recovery		12.9
Operation and maintenance expense incurred for Baxter Wilson recovery		15.3
Entergy Arkansas [Member]
Regulatory Assets [Line Items]
Expected NRC inspection costs excluding remediation and response costs		$ 38.0
Entergy Arkansas [Member] | Subsequent Event [Member]
Regulatory Assets [Line Items]
Expected NRC inspection costs excluding remediation and response costs			$ 35.0	$ 50.0
Entergy Wholesale Commodities [Member] | Pilgrim [Member]
Regulatory Assets [Line Items]
Capacity Supply Obligations in ISO New England | MW		677
Entergy Wholesale Commodities [Member] | Minimum [Member] | Pilgrim [Member]
Regulatory Assets [Line Items]
Expected NRC inspection costs		$ 45.0
Entergy Wholesale Commodities [Member] | Maximum [Member] | Pilgrim [Member]
Regulatory Assets [Line Items]
Expected NRC inspection costs		$ 60.0