Joint Ownership Agreements (Tables)

3 Months Ended

Mar. 31, 2017

Regulated Operations [Abstract]

Equity Method Investments

The carrying amounts of Southern Company Gas' equity method investments as of March 31, 2017 and December 31, 2016 and related income from those investments for the successor period ended March 31, 2017 and the predecessor period ended March 31, 2016 were as follows:

Balance Sheet Information	March 31, 2017		December 31, 2016
	(in millions)
SNG	$	1,430	$	1,394
Triton	44		44
Horizon Pipeline	31		30
PennEast Pipeline	30		22
Atlantic Coast Pipeline	42		33
Pivotal JAX LNG, LLC	26		16
Other	1		2
Total	$	1,604	$	1,541

Selected financial information of SNG for the first quarter 2017 is as follows:

Income Statement Information	Three Months Ended March 31, 2017
	(in millions)
Revenues	$	155
Operating income	$	84
Net income	$	66

Schedule of Other Nonoperating Income, by Component

	Successor		Predecessor
Income Statement Information	Three Months Ended March 31, 2017		Three Months Ended March 31, 2016
	(in millions)		(in millions)
SNG	$	34	$	—
Horizon Pipeline	1		1
PennEast Pipeline	3		—
Atlantic Coast Pipeline	1		—
Total	$	39	$	1