Other Comprehensive Income (Tables)

12 Months Ended

Dec. 31, 2015

Stockholders' Equity Note [Abstract]

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

Changes in accumulated other comprehensive (loss) income, net of tax, for the years ended Dec. 31, 2015 and 2014 were as follows:

	Year Ended Dec. 31, 2015
(Thousands of Dollars)	Gains and Losses on Cash Flow Hedges			Unrealized Gains and Losses onMarketable Securities		Defined Benefit Pension and Postretirement Items			Total
Accumulated other comprehensive (loss) income at Jan. 1	$	(57,628	)	$	110	$	(50,621	)	$	(108,139	)
Other comprehensive loss before reclassifications	(70		)	—		(7,906		)	(7,976		)
Losses reclassified from net accumulated other comprehensive loss	2,836			—		3,526			6,362
Net current period other comprehensive income (loss)	2,766			—		(4,380		)	(1,614		)
Accumulated other comprehensive (loss) income at Dec. 31	$	(54,862	)	$	110	$	(55,001	)	$	(109,753	)

	Year Ended Dec. 31, 2014
(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	$	(59,753	)	$	77	$	(46,599	)	$	(106,275	)
Other comprehensive (loss) income before reclassifications	(163		)	33		(7,517		)	(7,647		)
Losses reclassified from net accumulated other comprehensive loss	2,288			—		3,495			5,783
Net current period other comprehensive income (loss)	2,125			33		(4,022		)	(1,864		)
Accumulated other comprehensive (loss) income at Dec. 31	$	(57,628	)	$	110	$	(50,621	)	$	(108,139	)

Reclassifications out of Accumulated Other Comprehensive Loss

Reclassifications from accumulated other comprehensive loss for the years ended Dec. 31, 2015 and 2014 were as follows:

	Amounts Reclassifiedfrom Accumulated Other ComprehensiveLoss
(Thousands of Dollars)	Year Ended Dec. 31, 2015				Year Ended Dec. 31, 2014
(Gains) losses on cash flow hedges:
Interest rate derivatives	$	4,515		(a)	$	3,836		(a)
Vehicle fuel derivatives	131			(b)	(55		)	(b)
Total, pre-tax	4,646				3,781
Tax benefit	(1,810		)		(1,493		)
Total, net of tax	2,836				2,288
Defined benefit pension and postretirement (gains) losses:
Amortization of net loss	6,132			(c)	5,998			(c)
Prior service (credit) cost	(357		)	(c)	(344		)	(c)
Total, pre-tax	5,775				5,654
Tax benefit	(2,249		)		(2,159		)
Total, net of tax	3,526				3,495
Total amounts reclassified, net of tax	$	6,362			$	5,783

^(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 9 for details regarding these benefit plans.