CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands		Jun. 30, 2015	Dec. 31, 2014	[1]
Current assets
Cash and cash equivalents		$ 909,268	$ 1,193,308
Canadian government securities with maturities greater than 90 days at the date of acquisition		395,544	461,313
Accounts receivable, less allowance for doubtful accounts of $1,605 in 2015 and $1,609 in 2014		542,417	873,277
Inventories, at lower of cost or market
Crude oil		42,441	51,757
Materials and supplies		166,866	190,976
Prepaid expenses		114,547	77,281
Deferred income taxes		48,551	55,107
Assets held for sale		279,799	376,130
Total current assets		2,499,433	3,279,149
Property, plant and equipment, at cost less accumulated depreciation, depletion and amortization of $9,070,951 in 2015 and $9,503,524 in 2014		12,577,749	13,331,047
Deferred charges and other assets		72,768	62,582
Assets held for sale		14	50,960
Total assets		15,149,964	16,723,738
Current liabilities
Current maturities of long-term debt		14,942	465,388
Accounts payable		1,715,599	2,471,897
Income taxes payable		19,913	59,054
Liabilities associated with assets held for sale		56,334	151,548
Total current liabilities		1,806,788	3,147,887
Long-term debt, including capital lease obligation		3,264,868	2,517,669
Deferred income taxes		937,745	1,193,864
Asset retirement obligations		844,481	841,526
Deferred credits and other liabilities		429,485	441,048
Liabilities associated with assets held for sale		$ 551	$ 8,310
Stockholders' equity
Cumulative Preferred Stock, par $100, authorized 400,000 shares, none issued
Common Stock, par $1.00, authorized 450,000,000 shares, issued 195,055,724 shares in 2015 and 195,040,149 shares in 2014		$ 195,056	$ 195,040
Capital in excess of par value		892,553	906,741
Retained earnings		8,515,176	8,728,032
Accumulated other comprehensive loss	[2]	(429,917)	(170,255)
Treasury stock, 22,303,782 shares of Common Stock in 2015 and 17,540,636 shares of Common Stock in 2014, at cost		(1,306,822)	(1,086,124)
Total stockholders' equity		7,866,046	8,573,434
Total liabilities and stockholders' equity		$ 15,149,964	$ 16,723,738

[1] Reclassified to conform to current presentation.

[2] All amounts are presented net of income taxes.