Noncash or Part Noncash Divestiture, Debt Assumed

No definition available.

Name:	egn_NoncashorPartNoncashDivestitureDebtAssumed
Namespace Prefix:	egn_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Oil and Gas, Sales Price

+ References

No definition available.

+ Details

Name:	egn_OilandGasSalesPrice
Namespace Prefix:	egn_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount before tax of gain (loss) not previously recognized resulting from the disposal of a discontinued operation.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 205

-SubTopic 20

-Section 45

-Paragraph 3B

-URI http://asc.fasb.org/extlink&oid=51716988&loc=SL51721525-107759

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 205

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=51717284&loc=d3e1361-107760

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 205

-SubTopic 20

-Section 45

-Paragraph 3

-URI http://asc.fasb.org/extlink&oid=51716988&loc=d3e957-107759

+ Details

Name:	us-gaap_DiscontinuedOperationGainLossFromDisposalOfDiscontinuedOperationBeforeIncomeTax
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of consideration received or receivable for the disposal of assets and liabilities, including discontinued operation.

+ References

No definition available.

+ Details

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

- Definition

The aggregate amount of write-downs for impairments recognized during the period for long-lived assets held for abandonment, exchange or sale.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 28

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=56944662&loc=d3e3602-108585

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 360

-SubTopic 10

-Section 45

-Paragraph 15

-URI http://asc.fasb.org/extlink&oid=51824106&loc=d3e2611-110228

+ Details

Name:	us-gaap_ImpairmentOfLongLivedAssetsToBeDisposedOf
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

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

- Definition

The cash inflow associated with the amount received from the sale of a portion of the company's business, for example a segment, division, branch or other business, during the period.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Investing Activities

-URI http://asc.fasb.org/extlink&oid=6516133

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 12

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=56944662&loc=d3e3179-108585

+ Details

Name:	us-gaap_ProceedsFromDivestitureOfBusinesses
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Net quantities of an enterprise's interests in proved developed reserves of either crude oil (including condensate and natural gas liquids), natural gas, synthetic oil and gas, or other nonrenewable natural resource that is intended to be upgraded into synthetic oil and gas as of the beginning and the end of the year. "Net" quantities of reserves include those relating to the enterprise's operating and nonoperating interests in properties. Quantities of reserves relating to royalty interests owned are included in "net" quantities if the necessary information is available to the enterprise. "Net" quantities does not include reserves relating to interests of others in properties owned by the enterprise. The unit of measure for reserve quantities is defined as "barrels" for oil and synthetic oil reserves or "cubic feet" or "cubic meters" for natural gas and synthetic gas reserves.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 932

-SubTopic 235

-Section 50

-Paragraph 4

-URI http://asc.fasb.org/extlink&oid=51678428&loc=d3e61797-109447

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 932

-SubTopic 235

-Section 50

-Paragraph 9

-URI http://asc.fasb.org/extlink&oid=51678428&loc=d3e61884-109447

+ Details

Name:	us-gaap_ProvedDevelopedReservesVolume
Namespace Prefix:	us-gaap_
Data Type:	num:volumeItemType
Balance Type:	na
Period Type:	instant

- Details

Name:	us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis=egn_AlabamaGasCorporationMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis=egn_NorthLouisianaandEastTexasNaturalGasandOilPropertiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Discontinued Operations and Held for Sale Properties - Additional Information (Details) (USD $)	3 Months Ended		0 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Sep. 02, 2014	Dec. 31, 2013 Mcf
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Loss on disposal of discontinued operations		$ (1,667,000)
Impairment of oil and gas properties held-for-sale	0	1,667,000
Alabama Gas Corporation
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Amount of consideration received			1,600,000,000
Amount of debt assumed			267,000,000
Proceeds from sale			1,320,000,000
Loss on disposal of discontinued operations			726,500,000
North Louisiana and East Texas Natural Gas and Oil Properties
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Sale price of gas and oil properties		30,300,000
Impairment of oil and gas properties held-for-sale	$ 0	$ 1,667,000
North Louisiana and East Texas Natural Gas and Oil Properties \| Natural Gas
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proved Developed Reserves (Volume)				23,000,000
North Louisiana and East Texas Natural Gas and Oil Properties \| Oil
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proved Developed Reserves (Volume)				91,000