Risk Management and Fair Values (Schedules Of Valuation Techniques) (Details) $ in Millions	Mar. 31, 2017 USD ($)
Range from Average Percentage for Fair Value of Electricity Swaps	4.00%
Effect of Significant Unobservable Inputs on Fair Value of Electricity Swaps	$ 1
Fair Value of Electricity Swaps	$ 5

The range from the average percentage used when calculating the fair value of electricity swaps classified as Level 3 in the fair value hierarchy

No definition available.

Name:	etr_RangeFromAveragePercentageForFairValueOfElectricitySwaps
Namespace Prefix:	etr_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant