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SouthStar's percentage of contingently redeemable noncontrolling interest to our Consolidated Balance Sheets.

No definition available.

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SouthStar's percentage of Total current assets to our Consolidated Statement of Financial Position.

No definition available.

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Period Type:	instant

SouthStar's percentage of Total current liabilities to our Consolidated Statement of Financial Position.

No definition available.

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Namespace Prefix:	gas_
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Period Type:	instant

SouthStar's percentage of Total Stockholders Equity to our Consolidated Statement of Financial Position.

No definition available.

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Data Type:	num:percentItemType
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Represents goodwill and other intangible assets, minority interest percentage.

No definition available.

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SouthStar's percentage of Total long-term liabilities and other deferred credits to our Consolidated Statement of Financial Position.

No definition available.

Name:	gas_LongTermLiabilitiesAndOtherDeferredCreditsMinorityInterestPercentage
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Data Type:	num:percentItemType
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SouthStar's percentage of Total assets to our Consolidated Statement of Financial Position.

No definition available.

Name:	gas_TotalAssetsMinorityInterestPercentage
Namespace Prefix:	gas_
Data Type:	num:percentItemType
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Period Type:	instant

SouthStar's percentage of Total liabilities and Equity to our Consolidated Statement of Financial Position.

No definition available.

Name:	gas_TotalLiabilitiesAndEquityMinorityInterestPercentage
Namespace Prefix:	gas_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

SouthStar's percentage of Total liabilities to our Consolidated Statement of Financial Position.

No definition available.

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Namespace Prefix:	gas_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

Variable Interest Entity, Assets, Noncurrent, Percent

No definition available.

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

Sum of the carrying amounts as of the balance sheet date of all assets that are recognized. Assets are probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.18)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef
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Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 03
-Paragraph 12
-Article 7

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Sum of the carrying amounts as of the balance sheet date of all assets that are expected to be realized in cash, sold, or consumed within one year (or the normal operating cycle, if longer). Assets are probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

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

No definition available.

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Period Type:	duration

Carrying amount of finite-lived intangible assets, indefinite-lived intangible assets and goodwill. Goodwill is an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized. Intangible assets are assets, not including financial assets, lacking physical substance.

No definition available.

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Period Type:	instant

Sum of the carrying amounts as of the balance sheet date of all liabilities that are recognized. Liabilities are probable future sacrifices of economic benefits arising from present obligations of an entity to transfer assets or provide services to other entities in the future.

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Amount of liabilities and equity items, including the portion of equity attributable to noncontrolling interests, if any.

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Total obligations incurred as part of normal operations that are expected to be paid during the following twelve months or within one business cycle, if longer.

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Amount of obligation due after one year or beyond the normal operating cycle, if longer.

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As of the reporting date, the aggregate carrying amount of all noncontrolling interests which are redeemable by the (parent) entity (1) at a fixed or determinable price on a fixed or determinable date, (2) at the option of the holder of the noncontrolling interest, or (3) upon occurrence of an event that is not solely within the control of the (parent) entity. This item includes noncontrolling interest holder's ownership (or holders' ownership) regardless of the type of equity interest (common, preferred, other) including all potential organizational (legal) forms of the investee entity.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Amount of stockholders' equity (deficit), net of receivables from officers, directors, owners, and affiliates of the entity, attributable to both the parent and noncontrolling interests. Amount excludes temporary equity. Alternate caption for the concept is permanent equity.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
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-Section 55
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