Equity.

No definition available.

Name:	etr_EquityTextualAbstract
Namespace Prefix:	etr_
Data Type:	xbrli:stringItemType
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Period Type:	duration

- Definition

The number of stock options not included in the calculation of diluted common shares outstanding due to their antidilutive effect.

+ References

No definition available.

+ Details

Name:	etr_StockOptionsExcludedFromDilutedCommonSharesOutstandingCalculation
Namespace Prefix:	etr_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Aggregate dividends declared during the period for each share of common stock outstanding.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770

+ Details

Name:	us-gaap_CommonStockDividendsPerShareDeclared
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of shares of stock issued as of the balance sheet date, including shares that had been issued and were previously outstanding but which are now held in the treasury.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21463-112644

+ Details

Name:	us-gaap_SharesIssued
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Details

Name:	us-gaap_SubsequentEventTypeAxis=us-gaap_SubsequentEventMember
Namespace Prefix:
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Period Type:

Equity (Narrative) (Details) - $ / shares		3 Months Ended		6 Months Ended
Equity (Narrative) (Details) - $ / shares	Jul. 29, 2016	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Equity [Abstract]
Stock Options Excluded From Diluted Common Shares Outstanding Calculation		4,100,000	5,100,000	5,100,000	4,300,000
Shares, Issued		507,144		507,144
Common stock dividend (in dollars per share)		$ 0.85	$ 0.83	$ 1.70	$ 1.66
Subsequent Event [Member]
Equity [Abstract]
Common stock dividend (in dollars per share)	$ 0.85