Other Comprehensive Income (Tables)

3 Months Ended

Mar. 31, 2016

Stockholders' Equity Note [Abstract]

Changes in Accumulated Other Comprehensive Income (Loss), Net of Tax

Changes in accumulated other comprehensive income (loss), net of tax, for the three months ended March 31, 2016 and 2015 were as follows:

	Three Months Ended March 31, 2016
(Thousands of Dollars)	Gains and Losses on Cash Flow Hedges			Unrealized Gains and Losses on Marketable Securities		Defined Benefit Pension and Postretirement Items			Total
Accumulated other comprehensive (loss) income at Jan. 1	$	(19,090	)	$	105	$	(2,096	)	$	(21,081	)
Other comprehensive loss before reclassifications	(1		)	—		—			(1		)
Losses reclassified from net accumulated other comprehensive loss	223			—		19			242
Net current period other comprehensive income	222			—		19			241
Accumulated other comprehensive (loss) income at March 31	$	(18,868	)	$	105	$	(2,077	)	$	(20,840	)

	Three Months Ended March 31, 2015
(Thousands of Dollars)	Gains and Losses on Cash Flow Hedges			Unrealized Gains and Losses on Marketable Securities		Defined Benefit Pension and Postretirement Items			Total
Accumulated other comprehensive (loss) income at Jan. 1	$	(19,909	)	$	105	$	(1,010	)	$	(20,814	)
Other comprehensive (loss) income before reclassifications	(6		)	1		—			(5		)
Losses (gains) reclassified from net accumulated other comprehensive loss	208			—		(6		)	202
Net current period other comprehensive income (loss)	202			1		(6		)	197
Accumulated other comprehensive (loss) income at March 31	$	(19,707	)	$	106	$	(1,016	)	$	(20,617	)

Reclassifications out of Accumulated Other Comprehensive Loss

Reclassifications from accumulated other comprehensive loss for the three months ended March 31, 2016 and 2015 were as follows:

	Amounts Reclassified from Accumulated Other Comprehensive Loss
(Thousands of Dollars)	Three Months Ended March 31, 2016				Three Months Ended March 31, 2015
(Gains) losses on cash flow hedges:
Interest rate derivatives	$	346		(a)	$	337		(a)
Vehicle fuel derivatives	31			(b)	14			(b)
Total, pre-tax	377				351
Tax benefit	(154		)		(143		)
Total, net of tax	223				208
Defined benefit pension and postretirement (gains) losses:
Amortization of net loss	83			(c)	39			(c)
Prior service credit	(49		)	(c)	(49		)	(c)
Total, pre-tax	34				(10		)
Tax (benefit) expense	(15		)		4
Total, net of tax	19				(6		)
Total amounts reclassified, net of tax	$	242			$	202

^(a)  Included in interest charges.

^(b)  Included in O&M expenses.

^(c)  Included in the computation of net periodic pension and postretirement benefit costs. See Note 11 for details regarding these benefit plans.