Segment and Related Information (Tables)

12 Months Ended

Dec. 31, 2017

Segment Reporting Information [Line Items]

Financial data for business segments

Financial data for business segments and products and services for the years ended December 31, 2017, 2016, and 2015 was as follows:

	Electric Utilities
	Traditional Electric Operating Companies			Southern Power			Eliminations			Total		Southern Company Gas		All Other			Eliminations			Consolidated
	(in millions)
2017
Operating revenues	$	16,884		$	2,075		$	(419	)	$	18,540	$	3,920	$	741		$	(170	)	$	23,031
Depreciation and amortization	1,954			503			—			2,457		501		52			—			3,010
Interest income	14			7			—			21		3		11			(9		)	26
Earnings from equity method investments	1			—			—			1		106		(1		)	—			106
Interest expense	820			191			—			1,011		200		490			(7		)	1,694
Income taxes	1,021			(939		)	—			82		367		(307		)	—			142
Segment net income (loss)(a)(b)(c)	(193		)	1,071			—			878		243		(279		)	—			842
Total assets	72,204			15,206			(325		)	87,085		22,987		2,552			(1,619		)	111,005
Gross property additions	3,836			268			—			4,104		1,525		355			—			5,984
2016
Operating revenues	$	16,803		$	1,577		$	(439	)	$	17,941	$	1,652	$	463		$	(160	)	$	19,896
Depreciation and amortization	1,881			352			—			2,233		238		31			—			2,502
Interest income	6			7			—			13		2		20			(15		)	20
Earnings from equity method investments	2			—			—			2		60		(3		)	—			59
Interest expense	814			117			—			931		81		317			(12		)	1,317
Income taxes	1,286			(195		)	—			1,091		76		(216		)	—			951
Segment net income (loss)(a) (b)	2,233			338			—			2,571		114		(230		)	(7		)	2,448
Total assets	72,141			15,169			(316		)	86,994		21,853		2,474			(1,624		)	109,697
Gross property additions	4,852			2,114			—			6,966		618		41			(1		)	7,624
2015
Operating revenues	$	16,491		$	1,390		$	(439	)	$	17,442	$	—	$	152		$	(105	)	$	17,489
Depreciation and amortization	1,772			248			—			2,020		—		14			—			2,034
Interest income	19			2			1			22		—		6			(5		)	23
Earnings from equity method investments	1			—			—			1		—		(1		)	—			—
Interest expense	697			77			—			774		—		69			(3		)	840
Income taxes	1,305			21			—			1,326		—		(132		)	—			1,194
Segment net income (loss)(a) (b)	2,186			215			—			2,401		—		(32		)	(2		)	2,367
Total assets	69,052			8,905			(397		)	77,560		—		1,819			(1,061		)	78,318
Gross property additions	5,124			1,005			—			6,129		—		40			—			6,169

(a) Attributable to Southern Company.

(b) Segment net income (loss) for the traditional electric operating companies includes pre-tax charges for estimated probable losses on the Kemper IGCC of $3.4 billion ($2.4 billion after tax) in 2017, $428 million ($264 million after tax) in 2016, and $365 million ($226 million after tax) in 2015. See Note 3 under "Kemper County Energy Facility – Schedule and Cost Estimate" for additional information.

(c) Segment net income (loss) for the traditional electric operating companies also includes a pre-tax charge for the write-down of Gulf Power's ownership of Plant Scherer Unit 3 of $33 million ($20 million after tax) in 2017. See Note 3 under "Regulatory Matters – Gulf Power – Retail Base Rate Cases" for additional information.

Financial data for products and services

Products and Services

Electric Utilities' Revenues
Year	Retail		Wholesale		Other		Total
	(in millions)
2017	$	15,330	$	2,426	$	784	$	18,540
2016	15,234		1,926		781		17,941
2015	14,987		1,798		657		17,442

Southern Company Gas' Revenues
Year	Gas Distribution Operations		Gas Marketing Services		All Other		Total
	(in millions)
2017	$	3,024	$	860	$	36	$	3,920
2016	1,266		354		32		1,652

SOUTHERN Co GAS

Segment Reporting Information [Line Items]

Financial data for business segments

Financial data for business segments for the successor year ended December 31, 2017, the successor period of July 1, 2016 through December 31, 2016, and the predecessor periods of January 1, 2016 through June 30, 2016 and the year ended December 31, 2015 were as follows:

	Gas Distribution Operations			Gas Marketing Services			Wholesale Gas Services(a)			Gas Midstream Operations			Total			All Other			Eliminations			Consolidated
	(in millions)
Successor – Year ended December 31, 2017
Operating revenues	$	3,207		$	860		$	6		$	71		$	4,144		$	10		$	(234	)	$	3,920
Depreciation and amortization	391			62			2			18			473			28			—			501
Operating income (loss)	650			113			(51		)	(10		)	702			(37		)	—			665
Earnings from equity method investments	—			—			—			103			103			3			—			106
Interest expense	(153		)	(5		)	(7		)	(33		)	(198		)	(2		)	—			(200		)
Income taxes(b)	178			24			—			61			263			104			—			367
Segment net income (loss)(b)	353			84			(57		)	3			383			(140		)	—			243
Gross property additions	1,330			9			1			134			1,474			34			—			1,508
Successor – Total assets at December 31, 2017	19,358			2,147			1,096			2,241			24,842			12,184			(14,039		)	22,987
Successor – July 1, 2016 through December 31, 2016
Operating revenues	$	1,342		$	354		$	24		$	31		$	1,751		$	3		$	(102	)	$	1,652
Depreciation and amortization	185			35			1			9			230			8			—			238
Operating income (loss)	222			27			(2		)	(7		)	240			(43		)	—			197
Earnings from equity method investments	—			—			—			58			58			2			—			60
Interest expense	(105		)	(1		)	(3		)	(16		)	(125		)	44			—			(81		)
Income taxes	51			7			(3		)	16			71			5			—			76
Segment net income (loss)	77			19			—			20			116			(2		)	—			114
Gross property additions	561			5			1			54			621			11			—			632
Successor – Total assets at December 31, 2016	19,453			2,084			1,127			2,211			24,875			11,145			(14,167		)	21,853

	Gas Distribution Operations		Gas Marketing Services		Wholesale Gas Services(a)			Gas Midstream Operations			Total		All Other			Eliminations			Consolidated
	(in millions)
Predecessor – January 1, 2016 through June 30, 2016
Operating revenues	$	1,575	$	435	$	(32	)	$	25		$	2,003	$	4		$	(102	)	$	1,905
Depreciation and  amortization	178		11		1			9			199		7			—			206
Operating income (loss)	351		109		(69		)	(9		)	382		(61		)	—			321
EBIT	353		109		(68		)	(6		)	388		(60		)	—			328
Gross property additions	484		4		1			43			532		16			—			548
Predecessor – Year Ended December 31, 2015
Operating revenues	$	3,049	$	835	$	202		$	55		$	4,141	$	11		$	(211	)	$	3,941
Depreciation and  amortization	336		25		1			18			380		17			—			397
Operating income (loss)	571		152		112			(26		)	809		(63		)	—			746
EBIT	581		152		110			(23		)	820		(59		)	—			761
Gross property additions	957		7		2			27			993		34			—			1,027
Predecessor – Total assets at December 31, 2015	12,519		686		935			692			14,832		9,662			(9,740		)	14,754

(a)The revenues for wholesale gas services are netted with costs associated with its energy and risk management activities. A reconciliation of operating revenues and intercompany revenues is shown in the following table.

	Third Party Gross Revenues		Intercompany Revenues		Total Gross Revenues		Less Gross Gas Costs		Operating Revenues
	(in millions)
Successor – Year Ended December 31, 2017	$	6,152	$	481	$	6,633	$	6,627	$	6
Successor – July 1, 2016 through December 31, 2016	5,807		333		6,140		6,116		24
	(in millions)
Predecessor – January 1, 2016 through June 30, 2016	$	2,500	$	143	$	2,643	$	2,675	$	(32	)
Predecessor – Year Ended December 31, 2015	6,286		408		6,694		6,492		202

(b) Includes the impact of the Tax Reform Legislation and new income tax apportionment factors in several states resulting from the Company's inclusion in the consolidated Southern Company state tax filings.