Natural Gas Revenues

No definition available.

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- Definition

Number of Traditional Operating Companies

+ References

No definition available.

+ Details

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- Definition

The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=66011266&loc=d3e33918-111571

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- Definition

Number of segments reported by the entity. A reportable segment is a component of an entity for which there is an accounting requirement to report separate financial information on that component in the entity's financial statements.

+ References

No definition available.

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- Definition

The number of states the entity operates in as of the balance sheet date.

+ References

No definition available.

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- Definition

Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.1)
-URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688

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- 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.

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- Details

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- Details

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- Details

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Segment and Related Information - Textuals (Details) $ in Millions	3 Months Ended								6 Months Ended	12 Months Ended
	Dec. 31, 2017 USD ($) state segment	Sep. 30, 2017 USD ($)	Jun. 30, 2017 USD ($)	Mar. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Sep. 30, 2016 USD ($)	Jun. 30, 2016 USD ($)	Mar. 31, 2016 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2017 USD ($) state segment	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Segment Reporting Information [Line Items]
Number of traditional operating companies \| segment	4									4
Revenues	$ 5,629	$ 6,201	$ 5,430	$ 5,771	$ 5,181	$ 6,264	$ 4,459	$ 3,992		$ 23,031	$ 19,896	$ 17,489
Natural gas revenues										$ 3,791	1,596	0
Traditional Operating Companies
Segment Reporting Information [Line Items]
Number of states in which entity operates \| state	4									4
SOUTHERN Co GAS
Segment Reporting Information [Line Items]
Number of reportable segments \| segment										4
Number of states in which entity operates \| state	7									7
Revenues	$ 1,079	$ 565	$ 716	$ 1,560	$ 1,109	$ 543			$ 1,652	$ 3,920
Natural gas revenues									$ 1,596	3,791
Southern Natural Gas Company, LLC \| SOUTHERN Co GAS
Segment Reporting Information [Line Items]
Ownership percentage, equity method investment						50.00%
SOUTHERN POWER CO
Segment Reporting Information [Line Items]
Revenues										392	419	$ 417
Natural gas revenues										119	17
SOUTHERN Co GAS
Segment Reporting Information [Line Items]
Natural gas revenues										$ 23	$ 11