Other Comprehensive Income (Tables)

3 Months Ended

Mar. 31, 2018

Stockholders' Equity Note [Abstract]

Changes in Accumulated Other Comprehensive Loss, Net of Tax

Changes in accumulated other comprehensive loss, net of tax, for the three months ended March 31, 2018 and 2017 were as follows:

	Three Months Ended March 31, 2018
(Thousands of Dollars)	Gains and Losses on Cash Flow Hedges			Defined Benefit and Postretirement Items			Total
Accumulated other comprehensive loss at Jan. 1	$	(26,465	)	$	(267	)	$	(26,732	)
Losses reclassified from net accumulated other comprehensive loss	300			2			302
Net current period other comprehensive income	300			2			302
Accumulated other comprehensive loss at March 31	$	(26,165	)	$	(265	)	$	(26,430	)

	Three Months Ended March 31, 2017
(Thousands of Dollars)	Gains and Losses on Cash Flow Hedges			Defined Benefit and Postretirement Items			Total
Accumulated other comprehensive loss at Jan. 1	$	(22,780	)	$	(220	)	$	(23,000	)
Losses reclassified from net accumulated other comprehensive loss	246			1			247
Net current period other comprehensive income	246			1			247
Accumulated other comprehensive loss at March 31	$	(22,534	)	$	(219	)	$	(22,753	)

Reclassifications out of Accumulated Other Comprehensive Loss

Reclassifications from accumulated other comprehensive loss for the three months ended March 31, 2018 and 2017 were as follows:

	Amounts Reclassified from Accumulated Other Comprehensive Loss
(Thousands of Dollars)	Three Months Ended March 31, 2018				Three Months Ended March 31, 2017
Losses on cash flow hedges:
Interest rate derivatives	$	398		(a)	$	398		(a)
Total, pre-tax	398				398
Tax benefit	(98		)		(152		)
Total, net of tax	300				246
Defined benefit pension and postretirement losses:
Amortization of net loss	2			(b)	2			(b)
Total, pre-tax	2				2
Tax benefit	—				(1		)
Total, net of tax	2				1
Total amounts reclassified, net of tax	$	302			$	247

^(a)  Included in interest charges.

^(b)