Face (par) amount of debt instrument at time of issuance.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=114775744&loc=d3e28551-108399

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=114775985&loc=d3e28878-108400

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Face (par) amount of the original debt instrument that was repurchased.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Current portion of a debt security issued by a state, certain agencies or authorities, a local government, or development corporation to finance the construction of air- or water-pollution control facilities or sewage or solid waste disposal facilities pursuant to federal law. The bonds are backed by the credit of the beneficiary of the financing rather than the credit of the issuer.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.20)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

Name:	us-gaap_DebtInstrumentAxis=ee_A7252009SeriesRefundingBondsDue2040Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=ee_A7252009SeriesBRefundingBondsDue2040Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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Long-Term Debt and Financing Obligations (Details) - USD ($) $ in Thousands	May 22, 2019	Apr. 01, 2019	Feb. 01, 2019	Dec. 31, 2018
7.25% 2009 Series A Refunding Bonds, due 2040
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	3.60%
7.25% 2009 Series B Refunding Bonds, due 2040
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	3.60%
Pollution Control Bonds
Debt Instrument [Line Items]
Debt Instrument, Face Amount				$ 159,800
Long-term Debt, Subject for Redemption				$ 100,600
Pollution Control Bonds \| 7.25% 2009 Series A Refunding Bonds, due 2040
Debt Instrument [Line Items]
Debt Instrument, Face Amount	$ 63,500
Debt Instrument, Interest Rate, Stated Percentage	3.60%		7.25%
Debt Instrument, Repurchased Face Amount			$ 63,500
Pollution Control Bonds \| 7.25% 2009 Series B Refunding Bonds, due 2040
Debt Instrument [Line Items]
Debt Instrument, Face Amount	$ 37,100
Debt Instrument, Interest Rate, Stated Percentage	3.60%	7.25%
Debt Instrument, Repurchased Face Amount		$ 37,100