REGULATORY ASSETS AND LIABILITIES (Tables)

12 Months Ended

Dec. 31, 2019

SCHEDULE OF REGULATED ASSETS AND LIABILITIES [Line Items]

SCHEDULE OF REGULATED ASSETS AND LIABILITIES

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

		December 31, 2019
	Remaining Recovery Period	Current			Noncurrent			Total
		(Thousands of dollars)
Under-recovered purchased-gas costs	1 year	$	17,172		$	—		$	17,172
Pension and other postemployment benefit costs	See Note 13	21,213			373,266			394,479
Reacquired debt costs	8 years	812			5,677			6,489
MGP remediation costs	15 years	98			9,709			9,807
Ad-valorem tax	1 year	2,921			—			2,921
Other	1 to 19 years	5,224			2,384			7,608
Total regulatory assets, net of amortization		47,440			391,036			438,476
Federal income tax rate changes	(a)	(10,297		)	(503,518		)	(513,815		)
Over-recovered purchased-gas costs	1 year	(27,623		)	—			(27,623		)
Weather normalization	1 year	(7,281		)	—			(7,281		)
Total regulatory liabilities		(45,201		)	(503,518		)	(548,719		)
Net regulatory assets and liabilities		$	2,239		$	(112,482	)	$	(110,243	)

(a) Recovery period varies by jurisdiction. See discussion below for additional information regarding our regulatory liabilities related to federal income tax rate changes.

		December 31, 2018
	Remaining Recovery Period	Current			Noncurrent			Total
		(Thousands of dollars)
Under-recovered purchased-gas costs	1 year	$	25,083		$	—		$	25,083
Pension and other postemployment benefit costs	See Note 13	23,384			421,726			445,110
Reacquired debt costs	9 years	812			6,487			7,299
MGP remediation costs	15 years	—			7,724			7,724
Ad-valorem tax	1 year	1,070			—			1,070
Other	1 to 20 years	4,071			1,542			5,613
Total regulatory assets, net of amortization		54,420			437,479			491,899
Federal income tax rate changes	(a)	(30,934		)	(520,866		)	(551,800		)
Over-recovered purchased-gas costs	1 year	(13,668		)	—			(13,668		)
Weather normalization	1 year	(3,792		)	—			(3,792		)
Total regulatory liabilities		(48,394		)	(520,866		)	(569,260		)
Net regulatory assets and liabilities		$	6,026		$	(83,387	)	$	(77,361	)