Unconsolidated Affiliates (Tables)

12 Months Ended

Dec. 31, 2017

Equity Method Investments and Joint Ventures [Abstract]

Equity Method Investments [Table Text Block]

Distributions Received from Enable:

	Year Ended December 31,
	2017		2016		2015
	(in millions)
Investment in Enable’s common units	$	297	$	297	$	294

Limited Partner Interest in Enable:

	As of December 31,
	2017		2016			2015
CERC Corp.	54.1	%	54.1	%	(1)	55.4	%
OGE	25.7	%	25.7	%		26.3	%

(1) In November 2016, Enable completed a public offering of 11,500,000 common units of which 1,424,281 were sold by ArcLight Capital Partners, LLC. The common units issued and sold by Enable resulted in dilution of both CERC Corp.’s and OGE’s limited partner interest in Enable.

Enable Common Units Held:

	December 31, 2017
CERC Corp. (1)	233,856,623
OGE	110,982,805

(1) The 139,704,916 subordinated units previously owned by CERC Corp. converted into common units of Enable on a one-for-one basis, on August 30, 2017, at the end of the subordination period, as set forth in Enable’s Fourth Amended and Restated Agreement of Limited Partnership. Upon conversion, holders of common units resulting from the conversion of subordinated units have all the rights and obligations of unitholders holding all other common units, including the right to receive distributions pro rata made with respect to common units.

Transactions with Enable:

	Year Ended December 31,
	2017		2016		2015
	(in millions)
Reimbursement of transition services (1)	$	4	$	7	$	16
Natural gas expenses, including transportation and storage costs	115		110		117
Interest income related to notes receivable from Enable	—		1		8

(1) Represents amounts billed under the Transition Agreements, including the costs of seconded employees. Substantially all of the seconded employees became employees of Enable effective January 1, 2015. Actual transition services costs are recorded net of reimbursement.

	Year Ended December 31,
	2017		2016
	(in millions)
Accounts receivable for amounts billed for transition services	$	1	$	1
Accounts payable for natural gas purchases from Enable	13		10

Summarized consolidated income (loss) information for Enable is as follows:

	Year Ended December 31,
	2017		2016		2015
	(in millions)
Operating revenues	$	2,803	$	2,272	$	2,418
Cost of sales, excluding depreciation and amortization	1,381		1,017		1,097
Impairment of goodwill and other long-lived assets	—		9		1,134
Operating income (loss)	528		385		(712		)
Net income (loss) attributable to Enable	400		290		(752		)
Reconciliation of Equity in Earnings (Losses), net:
CERC’s interest	$	216	$	160	$	(416	)
Basis difference amortization (1)	49		48		8
Impairment of CERC’s equity method investment in Enable	—		—		(1,225		)
CERC’s equity in earnings (losses), net (2)	$	265	$	208	$	(1,633	)

(1) Equity in earnings of unconsolidated affiliates includes CERC’s share of Enable earnings adjusted for the amortization of the basis difference of CERC’s original investment in Enable and its underlying equity in net assets of Enable. The basis difference is being amortized over approximately 31 years, the average life of the assets to which the basis difference is attributed.

(2) These amounts include impairment charges totaling $1,846 million composed of CERC’s impairment of its equity method investment in Enable of $1,225 million and CERC’s share, $621 million, of impairment charges Enable recorded for goodwill and long-lived assets for the year ended December 31, 2015. This impairment is offset by $213 million of earnings for the year ended December 31, 2015.

Summarized consolidated balance sheet information for Enable is as follows:

	December 31,
	2017			2016
	(in millions)
Current assets	$	416		$	396
Non-current assets	11,177			10,816
Current liabilities	1,279			362
Non-current liabilities	2,660			3,056
Non-controlling interest	12			12
Preferred equity	362			362
Enable partners’ capital	7,280			7,420
Reconciliation of Investment in Enable:
CERC’s ownership interest in Enable partners’ capital	$	3,935		$	4,067
CERC’s basis difference	(1,463		)	(1,562		)
CERC’s investment in Enable	$	2,472		$	2,505