Financial Instruments and Risk Management (Tables)

6 Months Ended

Jun. 30, 2015

Financial Instruments and Risk Management [Abstract]

WTI Open Contracts

	Volumes
	(barrels per day)	Swap Prices
At June 30, 2015
July - September 2015	15,000	$62.84 per barrel
October - December 2015	15,000	$63.30 per barrel
At June 30, 2014
July - September 2014	26,000	$94.89 per barrel
October - December 2014	16,000	$92.33 per barrel

Fair Value of Derivative Instruments Not Designated as Hedging Instruments

	June 30, 2015			December 31, 2014
(Thousands of dollars)	Asset (Liability) Derivatives			Asset (Liability) Derivatives
Type of Derivative Contract	Balance Sheet Location	Fair Value		Balance Sheet Location	Fair Value
Commodity	Accounts receivable	$	7,419	Accounts receivable	$	23,168
Foreign exchange	Accounts payable		(11)	Accounts payable		(25)

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

			Gain (Loss)
		Three Months Ended			Six Months Ended
(Thousands of dollars)	Statement of Income	June 30,			June 30,
Type of Derivative Contract	Location		2015	2014	2015	2014
Commodity	Sales and other operating revenues	$	7,419	(36,041)	7,419	(54,455)
Foreign exchange	Interest and other income		(49)	1,464	14	4,900
		$	7,370	(34,577)	7,433	(49,555)

Carrying Value of Assets and Liabilities Recorded at Fair Value on Recurring Basis

	June 30, 2015					December 31, 2014
(Thousands of dollars)	Level 1		Level 2	Level 3	Total	Level 1	Level 2	Level 3	Total
Assets:
Commodity derivative         contracts		–	7,419	–	7,419	–	23,168	–	23,168
	$	–	7,419	–	7,419	–	23,168	–	23,168
Liabilities:
Nonqualified employee         savings plans	$	(15,032)	–	–	(15,032)	(14,408)	–	–	(14,408)
Foreign currency exchange         derivative contracts		–	(11)	–	(11)	–	(25)	–	(25)
	$	(15,032)	(11)	–	(15,043)	(14,408)	(25)	–	(14,433)