Financial Instruments and Risk Management (Tables)

12 Months Ended

Dec. 31, 2016

Financial Instruments and Risk Management [Abstract]

Fair Value of Derivative Instruments Not Designated as Hedging Instruments

	December 31, 2016				December 31, 2015
	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 Payable	$48,864	Accounts Receivable	$89,358	–	–
Foreign exchange	–	–	Accounts Payable	$73	–	–	Accounts Payable	$29

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

	Year Ended December 31, 2016			Year Ended December 31, 2015
(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	$	(63,412)	Sale and Other Operating Revenues	$	129,064
Foreign exchange	Interest and Other Income		26,714	Interest and Other Income		(4)
		$	(36,698)		$	129,060