CONSOLIDATED BALANCE SHEETS (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Current assets
Cash and cash equivalents	$ 816,694	$ 513,873
Canadian government securities with maturities greater than 90 days at the date of acquisition	491,604	532,093
Accounts receivable, less allowance for doubtful accounts of $7,856 in 2012 and $7,892 in 2011	1,639,428	1,554,184
Inventories, at lower of cost or market
Crude oil	249,853	189,320
Finished products	302,308	254,880
Materials and supplies	277,037	222,438
Prepaid expenses	239,444	93,397
Deferred income taxes	63,547	87,486
Assets held for sale	22,057	0
Total current assets	4,101,972	3,447,671
Property, plant and equipment, at cost less accumulated depreciation, depletion and amortization of $7,631,197 in 2012 and $6,861,494 in 2011	12,111,918	10,475,149
Goodwill	43,470	41,863
Deferred charges and other assets	145,994	173,455
Assets held for sale	186,483	0
Total assets	16,589,837	14,138,138
Current liabilities
Current maturities of long-term debt	45	350,005
Accounts payable and accrued liabilities	2,918,657	2,273,139
Income taxes payable	255,970	201,784
Liabilities associated with assets held for sale	49,949	0
Total current liabilities	3,224,621	2,824,928
Long-term debt	1,184,580	249,553
Deferred income taxes	1,379,526	1,230,111
Asset retirement obligations	613,240	615,545
Deferred credits and other liabilities	444,025	439,604
Liabilities associated with assets held for sale	127,087	0
Stockholders' equity
Cumulative Preferred Stock, par $100, authorized 400,000 shares, none issued	0	0
Common Stock, par $1.00, authorized 450,000,000 shares, issued 194,452,935 shares in 2012 and 193,909,200 shares in 2011	194,453	193,909
Capital in excess of par value	860,314	817,974
Retained earnings	8,105,611	7,460,942
Accumulated other comprehensive income	459,374	310,420
Treasury stock, 114,854 shares of Common Stock in 2012 and 185,992 shares of Common Stock in 2011, at cost	(2,994)	(4,848)
Total stockholders' equity	9,616,758	8,778,397
Total liabilities and stockholders' equity	$ 16,589,837	$ 14,138,138