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- Definition

Amount of write-down of assets recognized in the income statement. Includes, but is not limited to, losses from tangible assets, intangible assets and goodwill.

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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.

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- Definition

The aggregate costs related to goods produced and sold and services rendered by an entity during the reporting period. This excludes costs incurred during the reporting period related to financial services rendered and other revenue generating activities.

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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).

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Segment and Related Information - Schedule of Financial Data for Products and Services (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Concentration Risk [Line Items]
Operating revenues	$ 5,198	$ 4,620	$ 11,108	$ 9,638
Less Gross Gas Costs	231	144	814	583
Retail
Concentration Risk [Line Items]
Operating revenues	3,599	3,182	6,941	6,260
Wholesale
Concentration Risk [Line Items]
Operating revenues	546	472	1,091	889
Other
Concentration Risk [Line Items]
Operating revenues	175	168	346	320
Electric Utilities' Revenues
Concentration Risk [Line Items]
Operating revenues	4,407	3,884	8,524	7,579
Electric Utilities' Revenues \| Retail
Concentration Risk [Line Items]
Operating revenues	3,599	3,182	6,941	6,260
Electric Utilities' Revenues \| Wholesale
Concentration Risk [Line Items]
Operating revenues	546	472	1,091	889
Electric Utilities' Revenues \| Other
Concentration Risk [Line Items]
Operating revenues	262	230	492	430
Southern Company Gas' Revenues
Concentration Risk [Line Items]
Operating revenues	677	636	2,371	1,885
Southern Company Gas' Revenues \| Gas Distribution Operations
Concentration Risk [Line Items]
Operating revenues	706	583	1,898	1,596
Southern Company Gas' Revenues \| Wholesale Gas Services
Concentration Risk [Line Items]
Operating revenues	(110)	(19)	188	32
Southern Company Gas' Revenues \| Gas marketing services
Concentration Risk [Line Items]
Operating revenues	64	56	259	233
Southern Company Gas' Revenues \| Other
Concentration Risk [Line Items]
Operating revenues	17	16	26	24
Southern Company Gas' Revenues
Concentration Risk [Line Items]
Operating revenues	677	636	2,371	1,885
Asset impairment charges			82	0
Asset impairment charges, net of tax			58
Southern Company Gas' Revenues \| Wholesale Gas Services
Concentration Risk [Line Items]
Operating revenues	(110)	(19)	188	32
Less Gross Gas Costs	1,429	891	3,783	2,054
Third Party Gross Revenues \| Southern Company Gas' Revenues \| Wholesale Gas Services
Concentration Risk [Line Items]
Operating revenues	1,292	854	3,881	2,039
Intercompany Revenues \| Southern Company Gas' Revenues \| Wholesale Gas Services
Concentration Risk [Line Items]
Operating revenues	27	18	90	47
Total Gross Revenues \| Southern Company Gas' Revenues \| Wholesale Gas Services
Concentration Risk [Line Items]
Operating revenues	$ 1,319	$ 872	$ 3,971	$ 2,086