Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Current assets:
Cash and cash equivalents	$ 1,662,675	$ 1,077,429
Accounts receivable (less accumulated provision for doubtful accounts: $2,685 at September 30, 2015 and $5,311 at December 31, 2014)	147,229	306,085
Derivative instruments, at fair value	395,264	458,460
Prepaid expenses and other	57,653	62,349
Total current assets	2,262,821	1,904,323
Property, plant and equipment	15,364,032	13,608,151
Less: accumulated depreciation and depletion	4,091,834	3,531,337
Net property, plant and equipment	11,272,198	10,076,814
Other assets	205,087	83,763
Total assets	13,740,106	12,064,900
Current liabilities:
Current portion of long-term debt	160,000	166,011
Short-term loans	350,000	0
Accounts payable	265,407	444,077
Other current liabilities	215,709	223,391
Total current liabilities	991,116	833,479
Long-term debt	2,818,200	2,822,889
Deferred income taxes	1,875,552	1,750,870
Other liabilities and credits	302,965	284,599
Total liabilities	5,987,833	5,691,837
Stockholders’ equity:
Common stock, no par value, authorized 320,000 shares, shares issued: 175,347 at September 30, 2015 and 175,384 at December 31, 2014	2,384,312	1,895,632
Treasury stock, shares at cost: 22,807 at September 30, 2015 and 23,788 at December 31, 2014	(411,701)	(429,440)
Retained earnings	3,121,376	2,917,129
Accumulated other comprehensive income	77,530	199,494
Total common stockholders’ equity	5,171,517	4,582,815
Noncontrolling interests in consolidated subsidiaries	2,580,756	1,790,248
Total equity	7,752,273	6,373,063
Total liabilities and equity	$ 13,740,106	$ 12,064,900