Basis of presentation and significant accounting policies.

Name:	ep_BasisOfPresentationAndSignificantAccountingPoliciesNarrativeDetailsAbstract
Namespace Prefix:	ep
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of merger consideration in cash.

+ Details

Name:	ep_PercentageOfMergerConsiderationInCash
Namespace Prefix:	ep
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of merger consideration in shares.

+ Details

Name:	ep_PercentageOfMergerConsiderationInShares
Namespace Prefix:	ep
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of voting interest by major stock holder in the business acquirer.

+ Details

Name:	ep_PercentageOfVotingInterestByMajorStockHolderInBusinessAcquirer
Namespace Prefix:	ep
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Shareholders right to receive merger consideration cash per share condition three.

+ Details

Name:	ep_ShareholdersRightToReceiveMergerConsiderationCashPerShareConditionThree
Namespace Prefix:	ep
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration

- Definition

Shareholders right to receive merger consideration cash per share condition two.

+ Details

Name:	ep_ShareholdersRightToReceiveMergerConsiderationCashPerShareConditionTwo
Namespace Prefix:	ep
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration

- Definition

Shareholders right to receive merger consideration percentage of common stock condition one.

+ Details

Name:	ep_ShareholdersRightToReceiveMergerConsiderationPercentageOfCommonStockConditionOne
Namespace Prefix:	ep
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Shareholders right to receive merger consideration percentage of common stock condition three.

+ Details

Name:	ep_ShareholdersRightToReceiveMergerConsiderationPercentageOfCommonStockConditionThree
Namespace Prefix:	ep
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Shareholders right to receive merger consideration percentage of stock warrant condition one.

+ Details

Name:	ep_ShareholdersRightToReceiveMergerConsiderationPercentageOfStockWarrantConditionOne
Namespace Prefix:	ep
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Shareholders right to receive merger consideration percentage of stock warrant condition three.

+ Details

Name:	ep_ShareholdersRightToReceiveMergerConsiderationPercentageOfStockWarrantConditionThree
Namespace Prefix:	ep
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Shareholders right to receive merger consideration percentage of stock warrant condition two.

+ Details

Name:	ep_ShareholdersRightToReceiveMergerConsiderationPercentageOfStockWarrantConditionTwo
Namespace Prefix:	ep
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The total cost of the acquired entity including the cash paid to shareholders of acquired entities, fair value of debt and equity securities issued to shareholders of acquired entities, the fair value of the liabilities assumed, and direct costs of the acquisition.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 141

-Paragraph 51

-Subparagraph d

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

+ Details

Name:	us-gaap_BusinessAcquisitionCostOfAcquiredEntityPurchasePrice
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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.

+ Details

Name:	us-gaap_BusinessAcquisitionLineItems
Namespace Prefix:	us-gaap
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The exercise price of each class of warrants or rights outstanding.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Article 4

-Section 08

-Paragraph i

-Subparagraph 4

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 235

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.4-08.(i)(4))

-URI http://asc.fasb.org/extlink&oid=6881521&loc=d3e23780-122690

+ Details

Name:	us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights
Namespace Prefix:	us-gaap
Data Type:	us-types:perUnitItemType
Balance Type:	na
Period Type:	instant

- Definition

Face amount or stated value of common stock per share; generally not indicative of the fair market value per share.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 30

-Article 5

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 129

-Paragraph 4

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.29)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_CommonStockParOrStatedValuePerShare
Namespace Prefix:	us-gaap
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

Basis of Presentation and Significant Accounting Policies (Narrative) (Details) (USD $) In Billions, except Per Share data, unless otherwise specified	1 Months Ended	9 Months Ended
	Oct. 31, 2011	Sep. 30, 2011	Oct. 16, 2011	Dec. 31, 2010
Business Acquisition [Line Items]
Percentage of merger consideration in cash	57.00%
Par value per share		$ 3		$ 3
Basis of Presentation and Significant Accounting Policies (Narrative) (Details) [Abstract]
Business acquisition purchase price			$ 38
Percentage of voting right acquired			75.00%
Shareholders right to receive merger consideration percentage of stock warrant condition one		64.00%
Shareholders right to receive merger consideration percentage of stock warrant condition two		64.00%
Shareholders right to receive merger consideration percentage of stock warrant condition three		64.00%
Shareholders right to receive merger consideration cash per share condition two		$ 25.91
Shareholders Right To Receive Merger Consideration Cash Per Share Condition Three		$ 14.65
KMI Class P Common Stock [Member]
Business Acquisition [Line Items]
Percentage of merger consideration in shares	43.00%
Par value per share			$ 0.01
Common Stock Exercise Per Share			$ 40.00
Shareholders right to receive merger consideration percentage of common stock condition one		96.35%
Shareholders right to receive merger consideration percentage of common stock condition three		41.87%