Financial Instruments and Risk Management (Tables)

12 Months Ended

Dec. 31, 2015

Financial Instruments and Risk Management [Abstract]

Fair Value of Derivative Instruments Not Designated as Hedging Instruments

	December 31, 2015				December 31, 2014
	Asset Derivatives		Liability Derivatives		Asset Derivatives		Liability Derivatives
(Thousands of dollars)	Balance Sheet Location	Fair Value	Balance Sheet Location	Fair Value	Balance Sheet Location	Fair Value	Balance Sheet Location	Fair Value
Type of Derivative Contract
Commodity	Accounts Receivable	$89,358	–	–	Accounts Receivable	$23,168	–	–
Foreign exchange	–	–	Accounts Payable	$29	–	–	Accounts Payable	$25

Recognized Gains and Losses for Derivative Instruments Not Designated as Hedging Instruments

	Year Ended December 31, 2015			Year Ended December 31, 2014
(Thousands of dollars)	Location of Gain (Loss) Recognized in Income on Derivative	Amount of Gain (Loss) Recognized in Income on Derivative		Location of Gain (Loss) Recognized in Income on Derivative	Amount of   Gain (Loss) Recognized      in Income        on Derivative
Type of Derivative Contract
Commodity	Sale and Other Operating Revenues	$	129,064	Sale and Other Operating Revenues	$	17,887
Foreign exchange	Interest and Other Income		(4)	Interest and Other Income		4,226
		$	129,060		$	22,113