Contractual Maturity Due For, Mortgaged Backed Securities

Name:	ee_ContractualMaturityDueForMortgagedBackedSecurities
Namespace Prefix:	ee
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	duration

- Definition

Debt Instrument, Expected Weighted Average Maturity Year

+ Details

Name:	ee_DebtInstrumentExpectedWeightedAverageMaturityYear
Namespace Prefix:	ee
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	duration

- Definition

The amount of the transfers of assets or liabilities measured on a recurring basis out of Level 1 of the fair value hierarchy into Level 2.

+ Details

Name:	ee_FairValueLevel1ToLevel2TransfersAmount
Namespace Prefix:	ee
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Discloses the fair value amount of decommissioning trust assets.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 143
-Paragraph 22
-Subparagraph b

+ Details

Name:	us-gaap_DecommissioningTrustAssetsAmount
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

This element represents purchases, sales, issuances, and settlements (net) which have taken place during the period in relation to assets measured at fair value on a recurring basis using unobservable inputs (Level 3).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 157
-Paragraph 32
-Subparagraph c(2)

+ Details

Name:	us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPurchasesSalesIssuancesSettlements
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Financial Instruments And Investments (Narrative) (Details) (USD $)	3 Months Ended	6 Months Ended	12 Months Ended
	Jun. 30, 2011	Jun. 30, 2011 years MT	Jun. 30, 2011	Jun. 30, 2010	Dec. 31, 2009
Decommissioning trust funds				$ 162,700,000	$ 153,900,000
Contractual maturity due for, mortgaged backed securities		10
Transfers in and out of level 1 and level 2 fair value measurements	0	0	0
Purchases sales issuances and settlements related to the assets	$ 0	$ 0	$ 0
Maximum [Member]
Debt instrument, expected weighted average maturity year, range		7
Minimum [Member]
Debt instrument, expected weighted average maturity year, range		3