REGULATORY ASSETS AND LIABILITIES (Notes)

6 Months Ended

Jun. 30, 2016

SCHEDULE OF REGULATED ASSETS AND LIABILITIES [Line Items]

Schedule of Regulatory Assets and Liabilities

2. REGULATORY ASSETS AND LIABILITIES

The tables below present a summary of regulatory assets, net of amortization, and liabilities for the periods indicated:

	June 30, 2016
	Current			Noncurrent			Total
	(Thousands of dollars)
Under-recovered purchased-gas costs	$	10,635		$	—		$	10,635
Pension and postemployment benefit costs	22,988			397,068			420,056
Weather normalization	18,154			—			18,154
Reacquired debt costs	812			8,514			9,326
Other	2,056			5,066			7,122
Total regulatory assets, net of amortization	54,645			410,648			465,293
Accumulated removal costs (a)	—			(6,123		)	(6,123		)
Over-recovered purchased-gas costs	(18,186		)	—			(18,186		)
Ad valorem tax	(1,489		)	—			(1,489		)
Total regulatory liabilities	(19,675		)	(6,123		)	(25,798		)
Net regulatory assets (liabilities)	$	34,970		$	404,525		$	439,495

(a) Included in other deferred credits in our Balance Sheets.

	December 31, 2015
	Current			Noncurrent			Total
	(Thousands of dollars)
Under-recovered purchased-gas costs	$	13,336		$	—		$	13,336
Pension and postemployment benefit costs	15,670			425,175			440,845
Weather normalization	2,198			—			2,198
Reacquired debt costs	812			8,919			9,731
Other	909			1,769			2,678
Total regulatory assets, net of amortization	32,925			435,863			468,788
Accumulated removal costs (a)	—			(9,032		)	(9,032		)
Over-recovered purchased-gas costs	(22,884		)	—			(22,884		)
Ad valorem tax	(1,731		)	—			(1,731		)
Total regulatory liabilities	(24,615		)	(9,032		)	(33,647		)
Net regulatory assets (liabilities)	$	8,310		$	426,831		$	435,141

(a) Included in other deferred credits in our Balance Sheets.

Regulatory assets on our Balance Sheets, as authorized by various regulatory authorities, are probable of recovery. Base rates are designed to provide a recovery of costs during the period rates are in effect, but do not generally provide for a return on investment for amounts we have deferred as regulatory assets. All of our regulatory assets are subject to review by the respective regulatory authorities during future regulatory proceedings. We are not aware of any evidence that these costs will not be recoverable through either riders or base rates, and we believe that we will be able to recover such costs, consistent with our historical recoveries.

In January 2016, as a result of the OCC’s approval of our rate case in Oklahoma, we recorded a regulatory asset of $2.4 million to recover certain information technology costs incurred as a result of our separation from ONEOK in 2014, which will be recovered over four years.