Risk Management and Fair Values Schedules Of Valuation Techniques (Details) $ in Millions	Dec. 31, 2020 USD ($)
Range from Average Percentage for Fair Value of Electricity Swaps	475.00%
Effect of Significant Unobservable Inputs on Fair Value of Electricity Swaps	$ 4
Electricity Futures Forwards Swaps And Options [Member]
Fair Value of Electricity Swaps - Net Liability Position	$ 38

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