UNCONSOLIDATED AFFILIATES (Tables)

12 Months Ended

Dec. 31, 2017

Schedule of Equity Method Investments [Line Items]

Schedule of Equity Method Investments

Investments in Unconsolidated Affiliates - The following table sets forth our investments in unconsolidated affiliates for the periods indicated:

	Net Ownership Interest	December 31, 2017		December 31, 2016
		(Thousands of dollars)
Northern Border Pipeline	50%	$	396,800	$	328,456
Overland Pass Pipeline Company	50%	436,111		444,138
Roadrunner Gas Transmission	50%	93,048		94,548
Other	Various	77,197		91,665
Investments in unconsolidated affiliates (a)		$	1,003,156	$	958,807

(a) - Equity-method goodwill (Note A) was $38.8 million and $40.1 million at December 31, 2017 and 2016, respectively.

Equity In Net Earnings From Investments

Schedule of Equity Method Investments [Line Items]

Schedule of Equity Method Investments

Equity in Net Earnings from Investments and Impairments - The following table sets forth our equity in net earnings from investments for the periods indicated:

	Years Ended December 31,
	2017			2016		2015
	(Thousands of dollars)
Northern Border Pipeline	$	68,153		$	69,990	$	66,941
Overland Pass Pipeline Company	60,067			53,984		37,783
Roadrunner Gas Transmission	19,150			4,445		1,800
Other	11,908			11,271		18,776
Equity in net earnings from investments	$	159,278		$	139,690	$	125,300
Impairment of equity investments	$	(4,270	)	$	—	$	(180,583	)

Unconsolidated Affiliates Financial Information

Schedule of Equity Method Investments [Line Items]

Schedule of Equity Method Investments

Unconsolidated Affiliates Financial Information - The following tables set forth summarized combined financial information of our unconsolidated affiliates for the periods indicated:

	December 31, 2017			December 31, 2016
	(Thousands of dollars)
Balance Sheet
Current assets	$	151,907		$	143,317
Property, plant and equipment, net	$	2,490,692		$	2,579,607
Other noncurrent assets	$	14,793		$	20,784
Current liabilities	$	70,434		$	77,388
Long-term debt	$	479,050		$	649,539
Other noncurrent liabilities	$	53,830		$	69,265
Accumulated other comprehensive loss	$	(9,946	)	$	(7,450	)
Owners’ equity	$	2,064,024		$	1,954,966

	Years Ended December 31,
	2017		2016		2015
	(Thousands of dollars)
Income Statement
Operating revenues	$	639,102	$	578,542	$	524,496
Operating expenses (a)	$	277,121	$	260,753	$	304,930
Net income (a)	$	347,692	$	293,921	$	200,064
Distributions paid to us	$	196,114	$	196,717	$	155,918

(a) Includes long-lived asset impairment charges in 2015.