Financial Instruments and Risk Management (Tables)

6 Months Ended

Jun. 30, 2016

Financial Instruments and Risk Management [Abstract]

WTI Open Contracts

	Volumes
At June 30, 2016	(barrels per day)	Swap Prices
July – December 2016	25,000	$50.67	per barrel
January – December 2017	7,000	$50.16	per barrel
At June 30, 2015
July – September 2015	15,000	$62.84	per barrel
October – December 2015	15,000	$63.30	per barrel

Fair Value of Derivative Instruments Not Designated as Hedging Instruments

	June 30, 2016			December 31, 2015
(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	$	1,709	Accounts receivable	$	89,358
Foreign exchange	Accounts payable		(1)	Accounts payable		(29)

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

			Gain (Loss)
		Three Months Ended			Six Months Ended
(Thousands of dollars)		June 30,			June 30,
Type of Derivative Contract	Statement of Operations Location		2016	2015	2016	2015
Commodity	Sales and other operating revenues	$	(47,738)	7,419	(34,549)	7,419
Foreign exchange	Interest and other income		26,481	(49)	26,786	14
		$	(21,257)	7,370	(7,763)	7,433

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

	June 30, 2016					December 31, 2015
(Thousands of dollars)	Level 1		Level 2	Level 3	Total	Level 1	Level 2	Level 3	Total
Assets:
Commodity derivative         contracts		–	1,709	–	1,709	–	89,358	–	89,358
	$	–	1,709	–	1,709	–	89,358	–	89,358
Liabilities:
Nonqualified employee         savings plans	$	13,256	–	–	13,256	12,971	–	–	12,971
Foreign currency exchange         derivative contracts		–	1	–	1	–	29	–	29
	$	13,256	1	–	13,257	12,971	29	–	13,000

Nonrecurring Fair Value Measurements

	June 30, 2016
						Total
					Net Book	Pretax
					Value	(Noncash)
	Fair Value				Prior to	Impairment
		Level 1	Level 2	Level 3	Impairment	Loss
(Thousands of dollars)
Assets:
Impaired proved properties
Canada	$	–	–	71,967	167,055	95,088