Segment and Related Information (Tables)

12 Months Ended

Dec. 31, 2018

Segment Reporting [Abstract]

Financial data for business segments

Financial data for business segments and products and services for the years ended December 31, 2018, 2017, and 2016 was as follows:

	Electric Utilities
	Traditional Electric Operating Companies			Southern Power			Eliminations			Total			Southern Company Gas		All Other			Eliminations			Consolidated
	(in millions)
2018
Operating revenues	$	16,843		$	2,205		$	(477	)	$	18,571		$	3,909	$	1,213		$	(198	)	$	23,495
Depreciation and amortization	2,072			493			—			2,565			500		66			—			3,131
Interest income	23			8			—			31			4		8			(5		)	38
Earnings from equity method investments	(1		)	—			—			(1		)	148		2			(1		)	148
Interest expense	852			183			—			1,035			228		580			(1		)	1,842
Income taxes (benefit)	371			(164		)	—			207			464		(222		)	—			449
Segment net income (loss)(a)(b)(c)(d)	2,117			187			—			2,304			372		(453		)	3			2,226
Goodwill	—			2						2			5,015		298			—			5,315
Total assets	79,382			14,883			(306		)	93,959			21,448		3,285			(1,778		)	116,914
Gross property additions	6,077			315			—			6,392			1,399		414			—			8,205
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 (benefit)	1,021			(939		)	—			82			367		(307		)	—			142
Segment net income (loss)(a)(b)(e)(f)	(193		)	1,071			—			878			243		(279		)	—			842
Goodwill	—			2			—			2			5,967		299			—			6,268
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 (benefit)	1,286			(195		)	—			1,091			76		(216		)	—			951
Segment net income (loss)(a)(b)	2,233			338			—			2,571			114		(230		)	(7		)	2,448
Goodwill	—			2			—			2			5,967		282			—			6,251
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

(a) Attributable to Southern Company.

(b) Segment net income (loss) for the traditional electric operating companies includes pre-tax charges for estimated losses on plants under construction of $1.1 billion ($722 million after tax) in 2018, $3.4 billion ($2.4 billion after tax) in 2017, and $428 million ($264 million after tax) in 2016. See Note 2 under "Georgia Power – Nuclear Construction" and "Mississippi Power– Kemper County Energy Facility – Schedule and Cost Estimate" for additional information.

(c) Segment net income (loss) for Southern Power includes pre-tax impairment charges of $156 million ($117 million after tax) in 2018. See Note 15 under "Southern Power – Development Projects" and " – Sales of Natural Gas Plants" for additional information.

(d) Segment net income (loss) for Southern Company Gas includes a net gain on dispositions of $291 million ($51 million loss after tax) in 2018 related to the Southern Company Gas Dispositions and a goodwill impairment charge of $42 million in 2018 related to the sale of Pivotal Home Solutions. See Note 15 under "Southern Company Gas" for additional information.

(e) Segment net income (loss) for the traditional electric operating companies 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 2 under "Southern Company – Gulf Power" for additional information.

(f) Segment net income (loss) includes income tax expense of $367 million for the traditional electric operating companies, income tax benefit of $743 million for Southern Power, and income tax expense of $93 million for Southern Company Gas in 2017 related to the Tax Reform Legislation.

Financial data for business segments for the successor years ended December 31, 2018 and 2017, the successor period of July 1, 2016 through December 31, 2016, and the predecessor period of January 1, 2016 through June 30, 2016 were as follows:

	Gas Distribution Operations(a)(b)			Gas Pipeline Investments			Wholesale Gas Services(c)			Gas Marketing Services(b)(d)			Total			All Other			Eliminations			Consolidated
	(in millions)
Successor – Year ended December 31, 2018
Operating revenues	$	3,186		$	32		$	144		$	568		$	3,930		$	55		$	(76	)	$	3,909
Depreciation and amortization	409			5			2			37			453			47			—			500
Operating income (loss)	904			20			70			19			1,013			(98		)	—			915
Earnings from equity method investments	—			145			—			—			145			3			—			148
Interest expense	(178		)	(34		)	(9		)	(6		)	(227		)	(1		)	—			(228		)
Income taxes (benefit)	409			28			4			54			495			(31		)	—			464
Segment net income (loss)	334			103			38			(40		)	435			(63		)	—			372
Gross property additions	1,429			32			—			6			1,467			54			—			1,521
Successor – Total assets at December 31, 2018	17,266			1,763			1,302			1,587			21,918			11,112			(11,582		)	21,448
Successor – Year ended December 31, 2017
Operating revenues	$	3,207		$	17		$	6		$	860		$	4,090		$	64		$	(234	)	$	3,920
Depreciation and amortization	391			2			2			62			457			44			—			501
Operating income (loss)	645			10			(51		)	113			717			(57		)	—			660
Earnings from equity method investments	—			103			—			—			103			3			—			106
Interest expense	(153		)	(26		)	(7		)	(5		)	(191		)	(9		)	—			(200		)
Income taxes(e)	178			109			—			24			311			56			—			367
Segment net income (loss)(e)	353			(22		)	(57		)	84			358			(115		)	—			243
Gross property additions	1,330			117			1			9			1,457			51			—			1,508
Successor – Total assets at December 31, 2017	19,358			1,699			1,096			2,147			24,300			12,726			(14,039		)	22,987
Successor – July 1, 2016 through December 31, 2016
Operating revenues	$	1,342		$	3		$	24		$	354		$	1,723		$	31		$	(102	)	$	1,652
Depreciation and  amortization	185			—			1			35			221			17			—			238
Operating income (loss)	225			1			(2		)	27			251			(52		)	—			199
Earnings from equity method investments	—			58			—			—			58			2			—			60
Interest expense	(105		)	(10		)	(3		)	(1		)	(119		)	38			—			(81		)
Income taxes (benefit)	51			21			(3		)	7			76			—			—			76
Segment net income (loss)	77			29			—			19			125			(11		)	—			114
Gross property additions	561			51			1			5			618			14			—			632
Successor – Total assets at December 31, 2016	19,453			1,659			1,127			2,084			24,323			11,697			(14,167		)	21,853

	Gas Distribution Operations(a)(b)		Gas Pipeline Investments		Wholesale Gas Services(c)			Gas Marketing Services(b)(d)		Total		All Other			Eliminations			Consolidated
	(in millions)
Predecessor – January 1, 2016 through June 30, 2016
Operating revenues	$	1,575	$	3	$	(32	)	$	435	$	1,981	$	26		$	(102	)	$	1,905
Depreciation and  amortization	178		—		1			11		190		16			—			206
Operating income (loss)	353		3		(69		)	109		396		(73		)	—			323
EBIT	353		3		(68		)	109		397		(69		)	—			328
Gross property additions	484		40		1			4		529		19			—			548

(a) Operating revenues for the three gas distribution operations dispositions were $244 million, $399 million, and $168 million for the successor years ended December 31, 2018 and 2017 and the successor period of July 1, 2016 through December 31, 2016, respectively, and $215 million for the predecessor period ended June 30, 2016. See Note 15 under "Southern Company Gas" for additional information.

(b) Segment net income for gas distribution operations includes a gain on dispositions of $324 million ($16 million after tax) for the year ended December 31, 2018. Segment net income for gas marketing services includes a loss on disposition of $(33) million ($(67) million loss after tax) and a goodwill impairment charge of $42 million for the year ended December 31, 2018 recorded in contemplation of the sale of Pivotal Home Solutions. See Note 15 under "Southern Company Gas" for additional information.

(c)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, 2018	$	6,955	$	451	$	7,406	$	7,262	$	144
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
Predecessor – January 1, 2016 through June 30, 2016	2,500		143		2,643		2,675		(32		)

(d) Operating revenues for the gas marketing services disposition were $55 million, $129 million, and $56 million for the successor years ended December 31, 2018 and 2017 and the successor period of July 1, 2016 through December 31, 2016, respectively, and $64 million for the predecessor period ended June 30, 2016 See Note 15 under "Southern Company Gas" for additional information.

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

Financial data for products and services

Products and Services

Electric Utilities' Revenues
Year	Retail		Wholesale		Other		Total
	(in millions)
2018	$	15,222	$	2,516	$	833	$	18,571
2017	15,330		2,426		784		18,540
2016	15,234		1,926		781		17,941

Southern Company Gas' Revenues
Year	Gas Distribution Operations		Gas Marketing Services		All Other		Total
	(in millions)
2018	$	3,155	$	568	$	186	$	3,909
2017	3,024		860		36		3,920
2016	1,266		354		32		1,652