Debt Issuance Authorization Period

No definition available.

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Namespace Prefix:	ee_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of public utilities affected

+ References

No definition available.

+ Details

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Namespace Prefix:	ee_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Period to comply with regulatory agency order

+ References

No definition available.

+ Details

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Namespace Prefix:	ee_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Proceeds from issuance of common stock, authorization requested from regulatory agency for public utilities

+ References

No definition available.

+ Details

Name:	ee_Proceedsfromissuanceofcommonstockrequested
Namespace Prefix:	ee_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Show cause order issued by the Federal Energy Regulatory Commission

+ References

No definition available.

+ Details

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Namespace Prefix:	ee_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

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

+ References

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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Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

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

+ References

No definition available.

+ Details

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

- Definition

Percentage of domestic federal statutory tax rate applicable to pretax income (loss).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB TOPIC 6.I)
-URI http://asc.fasb.org/extlink&oid=34349781&loc=d3e330036-122817

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-Name Accounting Standards Codification
-Topic 740
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-Section 50
-Paragraph 12
-URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32687-109319

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
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-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 13
-URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32698-109319

+ Details

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

- Definition

Amount of current borrowing capacity under the credit facility considering any current restrictions on the amount that could be borrowed (for example, borrowings may be limited by the amount of current assets), but without considering any amounts currently outstanding under the facility.

+ 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 210.5-02.19(b),22(b))
-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

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ 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 210.5-02.19(b),22(b))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- 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

Name:	us-gaap_RegulatoryAgencyAxis=ee_FercMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

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

- Details

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

- Details

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Namespace Prefix:
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Balance Type:
Period Type:

- Details

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Namespace Prefix:
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Balance Type:
Period Type:

- Details

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Balance Type:
Period Type:

- Details

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Regulation Regulation Narrative - FERC Jurisdiction (Details) $ in Millions				3 Months Ended		6 Months Ended		12 Months Ended
	Jan. 30, 2019 USD ($)	Mar. 15, 2018	Nov. 15, 2017	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018	Dec. 31, 2017	May 22, 2019 USD ($)	Apr. 01, 2019 USD ($)	Feb. 01, 2019 USD ($)	Sep. 13, 2018 USD ($)	Jun. 28, 2018 USD ($)	Oct. 31, 2017 USD ($)
Public Utilities, General Disclosures [Line Items]
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent				21.00%	21.00%	21.00%	21.00%	21.00%	35.00%
Debt Issuance Authorization Period			2 years
Maximum
Public Utilities, General Disclosures [Line Items]
Proceeds from issuance of common stock, requested	$ 200.0
7.25% 2009 Series A Refunding Bonds, due 2040
Public Utilities, General Disclosures [Line Items]
Debt Instrument, Interest Rate, Stated Percentage										3.60%
7.25% 2009 Series B Refunding Bonds, due 2040
Public Utilities, General Disclosures [Line Items]
Debt Instrument, Interest Rate, Stated Percentage										3.60%
FERC
Public Utilities, General Disclosures [Line Items]
Show Cause Orders issued, Number		2
Number of public utilities affected		48
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent									35.00%
Line of Credit Facility, Current Borrowing Capacity													$ 350.0
FERC \| Maximum
Public Utilities, General Disclosures [Line Items]
Period to comply with order from regulatory agency		60 days
Proceeds from issuance of common stock, requested	200.0
FERC \| Long-term Debt \| Maximum
Public Utilities, General Disclosures [Line Items]
Debt Instrument, Face Amount	225.0														$ 350.0
FERC \| RGRT \| Maximum
Public Utilities, General Disclosures [Line Items]
Debt Instrument, Face Amount															65.0
FERC \| 7.25% 2009 Series A Refunding Bonds, due 2040
Public Utilities, General Disclosures [Line Items]
Debt Instrument, Face Amount	$ 63.5									$ 63.5					$ 63.5
Debt Instrument, Interest Rate, Stated Percentage	7.25%									3.60%		7.25%			7.25%
Debt Instrument, Repurchased Face Amount												$ 63.5
FERC \| 7.25% 2009 Series B Refunding Bonds, due 2040
Public Utilities, General Disclosures [Line Items]
Debt Instrument, Face Amount	$ 37.1									$ 37.1					$ 37.1
Debt Instrument, Interest Rate, Stated Percentage	7.25%									3.60%	7.25%				7.25%
Debt Instrument, Repurchased Face Amount											$ 37.1
FERC \| Senior Notes \| Maximum
Public Utilities, General Disclosures [Line Items]
Debt Instrument, Face Amount	$ 100.6
FERC \| 4.22% Senior Notes, due 2028 \| Senior Notes
Public Utilities, General Disclosures [Line Items]
Debt Instrument, Face Amount														$ 125.0
Debt Instrument, Interest Rate, Stated Percentage														4.22%
FERC \| 4.07% RGRT Senior Notes, due 2025 \| Senior Notes
Public Utilities, General Disclosures [Line Items]
Debt Instrument, Face Amount														$ 65.0
Debt Instrument, Interest Rate, Stated Percentage														4.07%
FERC \| Revolving Credit Facility
Public Utilities, General Disclosures [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	$ 400.0