Commitments and Contingencies Commitments And Contingencies (Narrative) (Details) (Details) $ in Millions	6 Months Ended	12 Months Ended
	Jun. 30, 2015 USD ($)	Dec. 31, 2016 USD ($)	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	$ 27.8
Capital expense related to Baxter Wilson recovery	12.7
Operation and maintenance expense incurred for Baxter Wilson recovery	15.1
Entergy Arkansas [Member]
Regulatory Assets [Line Items]
Expected NRC inspection costs excluding remediation and response costs	$ 18.0
Entergy Arkansas [Member] | Subsequent Event [Member]
Regulatory Assets [Line Items]
Expected NRC inspection costs excluding remediation and response costs		$ 35.0	$ 50.0